thoughts on cooling


Staff member
read this, yes theres a good deal of info in the links worth the time and effort, and yes its well worth your time to read thru
keep in mind, that if your engine is mechanically functioning correctly, IE there are no problems like leaking head gaskets or the wrong head gasket or a cracked head etc, and you've significantly increased horsepower or swapped too a larger engine, heat levels will be higher,. and if the radiator fans and water pump don,t have the ability to transfer heat from the engine at that HIGHER rate of heat being generated than the engine coolants being heated ,can transfer heat out to the outside air flow, theres not much you can do to prevent over heating, you may need a larger or more efficient radiator.
adding an auxiliary added oil or transmission fluid cooler to a vehicles cooling system to reduce the amount of heat the radiator and engine coolant needs to deal with, is also a well proven route to reducing engine operating temps.
adding an efficient oil cooler with a few extra quarts of oil capacity and a powered fan, is a very effective way to reduce engine temps.


You'll generally want to have a minimum of 1.5 to-2 square inches of frontal surface area on a radiator per cubic inch of displacement,and the depth , tube design and fin count will have a pronounced effect on heat transfer efficiency.
look the basics are that in any correctly functioning cooling system the radiator and fans forcing air thru the radiator MUST be capable of transferring the heat in the coolant passing thru it to the outside air flow at a rate thats significantly faster than the heat generated by the engine is absorbed by the coolant, the t-stats only major function or purpose, is to restrict flow UNTIL the coolant reaches and or exceeds a designed in temperature range, at which point it opens and remains open unless the coolant temps fall below that designed temp. limit.
keep in mind a t-stat does not limit the cooler coolant entering the engine, its function is to keep the coolant flow through the engine minimized until its absorbed enough heat to reach the t-stats opening temp that allows the coolant to flow out of the engine.
also be aware that you can attack the heat control issues you might have from two directions, you can concentrate on removing heat from the engine more effectively with a larger more efficient radiator, bigger fans,, adding an alternator that allows more AMPS to spin those fans , adding more effective duct work, adding oil coolers, transmission coolers or a larger capacity baffled oil pan, adding heat exhaust vents to the hood,adding additives to the coolant that reduce the tendency to boil, like WATER WETTER, etc. or you can concentrate on reducing the heat generated thru control of your fuel/air mix ratio, ignition advance curve, timing and exhaust restriction.

Id also point out that chevy water pumps can be purchased that are designed to spin in either clock wise or counter clock wire rotation and installing the wrong part number will cause big problems, ID also point out that all radiators collect crud and become restrictive to flow and much less effective at transferring heat to outside air flow over time, especially if the wrong coolant or water containing excessive mineral content are used so you might want to have yours cleaned out, rebuilt or replaced, if thats needed, after taking it out, an inspection indicates the correct course, a new aluminum radiator, in the largest size quality, radiator, that fits you can afford, is usually a good idea, if it needs replacing

honestly are you thinking this through?
the larger the percentage of the cooling systems total coolant in the radiator and the more efficient you can make the rate of heat transfer the better, you want to maximize the radiator surface area, where its transferring heat to the outside air flow vs in the engine absorbing heat, vs in the engine
coolant is in constant motion once the t-stat opens, the total air flow per minute and the surface area of the radiator tubes and fins has a huge effect on that heat transfer efficiency, the rate of coolant flow through the radiator from the engine and back into the engine, has less effect on the rate and efficiency of heat absorption and heat transfer to the cooler outside air than the total surface area of the radiator and the mass , and temperature of the air being forced through and over that radiators surface by the fans and duct design and the surface area of the coolant transfer tubes and fins,( And the type of coolant being used and the pressure the system is designed to operate at.)
oil flow does most of the initial cooling as it transfers heat it absorbed on the surfaces of the pistons and valve train components, bearings and blocks inner surfaces, to the block, where coolant flowing through the blocks internal surfaces absorbs that transferred heat, and coolant flow transports it to the radiator ,
hot oil flows over internal parts that can easily reach well over 300F but its flowing back over the block where that heats absorbed.
for every ounce of coolant flowing through the closed loop cooling system, as one ounce of coolant, leaves the radiator to enter the engine and ABSORB HEAT as it travels through the engine, the exact same volume enters the radiator where air flow through the radiator absorbs heat out of the coolant entering and passing through the radiators coolant tubes with the radiators finned surface greatly adding to the surface area that air flow flows over. once the coolant is flowing through the t-stat, its like links on a bicycles drive chain, as one link leaves the gear on the petals another takes its place on the opposite side of the drive gear, in the same way, once the coolant flows , hot coolant enters the upper radiator at the same rate as it exits back into the engine to re-absorb heat.
the air flow through the radiator is in most cases well over 100F degrees or more cooler than the coolant leaving the engine after it absorbs engine heat from friction and combustion, the rate at where the coolant lows is usually controlled by the water pump and flow rate of outside air flow the radiator fans and duct work provide to allow the mass of cooling air to be forced over the surface of the radiator tubes and finned surfaces, that can be several layers thick and cover hundreds or even thousands of square inches of surface area. electric cooling
fans or engine driven fans move hundreds or in some cases thousands of cubic feet of outside air per minute over the radiators surfaces to absorb that heat
from the coolant to that outside air.



YOUR EFFECTIVELY BEATING A DEAD HORSE if your not addressing that heat dissipation factor up front.
If your having cooling issues while the cars stationary but not when the cars moving theres an excellent chance that the problem is lack of low speed air flow rates, a larger more effective fan or a more efficient fans or adding a pusher fan or use of a more efficient fan shroud would help.
clear pictures of the car,s engine compartment, radiator fans, fan shroud etc would help here a great deal.
keep in mind oil does a good deal of the heat transfer, in an engine, so an oil pan with a larger than stock capacity and an oil cooler with a built in electrical fan can do a good deal to lower engine temps. if your engine has an efficient oil cooler and transmission fluid cooler, your significantly reducing the heat load on the radiator.

keep in mind automatic transmissions tend to add a significant amount of heat to radiators that use the lower section to cool the transmission, adding a large efficient trans fluid cooler to the car, thats separate, from the OEM radiator and has its own electrical fan, can also significantly reduce the heat loads on the radiator
BTW one frequently overlooked factor, in cooling your engine or adding an additional oil cooler, is your alternator size,in amps and wiring the alternator correctly, if your running a 70amp-100 amp stock alternator and using electric fans to cool the engine,its not going to provide the power required to spin the fans nearly fast enough to cool the engine like a better 200 amp alternator can, Ive seen several corvettes cure cooling issues by swapping to 200 amp alternators, that simply allowed the electrical cooling fans to spin significantly faster.
engine heat can be a huge issue, detonation can destroy even a well built engine, I have tried to maintain an 8:1-8.4:1 dynamic compression ratio and a .040-.042 quench in most of my engines,I try to keep the oil temps at no more than 220F most of the time and ideally under 215F, I try to keep coolant temps under 190F most of the time and try to avoid getting coolant over 215 f, keep in mind that you can,t audibly hear detonation in most engines in the upper rpm range until it becomes rather extreme and potentially rather destructive, and that just because you can,t hear it at lower rpms or when its not happening consistently, its not an indication that the cumulative damage is not occurring over time.
I lost count of the guys I know who built engines that "for no apparent reason... busted pistons or rings" when those engines get torn down and closely inspected DETONATION is frequently a prime suspect, and todays crappy fuel octane is a prime contributor.
installing piston rings with the wrong end gap , pistons with the wrong bore clearance,or bearings with incorrect clearances or not clearancing a valve train correctly will all cause an engine to either run hot or have parts fail.
every combos different and simple things like polishing combustion chambers. retarding a cam a few degrees,using a larger more efficient radiator, and changing the fuel/air ratio and ignition advance curve or adding a highly effective scavenging header on a low restriction exhaust can make or brake a combo as far as its tendency to get into detonation.

so obviously the larger the surface area of the fins and coolant tubes are and more efficient the radiator and the coolant system, is at transferring heat to the outside air flow , the better the system will function, so maximizing both coolant and air flow rates becomes critical to heat transfer, the cooling system, MUST have the potential to cool the coolant to below the temperature that the thermostat is designed to keep the coolant temps limited to so that the t-stat can add cooler, coolant as it is required to maintain the intended operational temp range.

do you currently have a FAN SHROUD , a clutch fan hub and efficient multi blade fan that fits the shroud around the engine driven puller fan?
having efficient components helps, increase cooling efficiency remarkably,in an IDEAL set up, an effective radiator should generally have about 1.5-to-2 square inches of surface frontal area or greater for every cubic inch of engine displacement,and its generally considered smart to have a minimum 1.5-to-2 square inches of frontal surface fin area PER HP in a radiator,obviously both calculations will produce different results so go with the larger surface area to be fairly safe. if your intention is max effective heat transfer , obviously factors like type of fans duct work and additional oil coolers and a 7-8 quart oil pan all help dissipate heat generated.

and yes its VERY LIKELY your current radiator size is woefully undersized and the area its mounted in can,t be easily increased, if you have significantly increased your engine power out put! 3-&-4 row aluminum radiators that hold more coolant volume, allow the liquid to transfer heat more efficiently, and allow the coolant to pass thru a bit slower.
adding an auxiliary oil cooler with a powered electrical fan can reduce the heat load on the radiator

total surface area of the radiator should ideally be at or more than about 1.5-2 sq inches per cubic inch of engine displacement
in theory that requires about a 24 inch tall x 32 inch wide
496 x 1.5=744
24 x 32=768
obviously clearance issues fitting that large a radiator become a problem so multi tube radiator designs are rather common on performance applications



what I find absolutely amazing is the number of people that have ordered replacement radiators ,
without accurately measuring the original radiator, and then accurately, measuring, the space its seated been in,
and the distance available in front of the O.E.M radiator and behind that original radiator,
if you want too select and install a thicker, more efficient heat transfer core, aftermarket radiator
thats thicker has more fins and surface area and larger coolant flow tubes.





If your replacing a damaged or missing fan shroud ,it doesn,t need to be an EXACT match,to the original O.E.M. component
but it should be an IMPROVED design over what its replacing'
in both structural strength and ideally in cosmetic appeal,
a bit of custom fabrication if done correctly,
will add rather than detract from the over all builds visual and functional presents,
ideally you want people to look at what you've done and think
"WOW! why didn,t I think of that!.... DAMN THATS IMPRESSIVE"

rather than "
what the hell was that guy thinking when he installed that crap!"
and sometimes
the difference is only in a few extra minutes grinding welds,
the type of fasteners used, the care taken in the fabrication and careful fitting,
thinking through the over all design,
or a bit of matching paint





Id also point out that,adding an auxiliary oil and/or trans mission fluid cooler with a powered fan, too the car, helps remove heat far more effectively and can remove a great deal of heat load from the radiator well before the coolant in the engine needs to deal with it
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any radiator needs a good large and effective multi blade fan shroud to match the fan and make air flow through that radiator much more efficient




buy and add a bottle, this stuff allows the micro surface contact of water inside the cylinder heads to allow a bit more efficient heat transfer rate, its no miracle, product , but its generally good for a 7-9 degree reduction in coolant heat.
tips on reducing the heat of your engine coolant,

you might also consider adding an oil cooler as oil does a great deal of the heat transfer inside any engine, thus reducing oil temperatures tends to reduce coolant temperatures.
Id also point out that,adding an auxiliary oil and/or trans mission fluid cooler with a powered fan, too the car, helps remove heat far more effectively and can remove a great deal of heat load from the radiator well before the coolant in the engine needs to deal with it





one fact often over looked is that radiator designs vary wildly, and the number of fins per inch of surface area and width of radiator coolant flow tubes can significantly increase or decrease thermal heat transfer efficiency., fin counts vary from 8 to 22 fins per inch on various radiator designs Ive seen.

thus a radiator might measure say 18" tall by 24" wide but depending on design, and fin and tube count, might actually have a radically more or less efficient heat transfer rate.




if your cooling system was working correctly and you have not made changes and it suddenly starts to over heat, obviously something changed so before you panic check the obvious causes like low coolant levels,low oil levels,loose connections, defective sensors, trash in the radiator fins, or a sticking t-stat or loose belts and defective hoses.
now if you reduce the heat load on the radiator and its coolant with an auxiliary oil or transmission fluid cooler that obviously will effectively reduce the heat that needs to be transferred from the engine coolant to the air flow thru the radiator fins.
heat in the engine is absorbed by both the oil and the coolant, both can be used to transfer that heat to the outside air to be dispersed, both systems in most stock cars will easily keep up with the stock engines they were designed for but as hp increases so does the heat generated.
adding an oil and transmission fluid cooler to your system tends to reduce the heat loads on the radiator so that is always an option to increase total cooling capacity, but in many cars youll eventually need to upgrade to a larger more efficient aluminum radiator if you significantly increase the engines power range as that increase generates more total heat.

first a few basics

(1) an engine driven fan with the proper duct work will almost always out cool the typical electric fans on identical radiators, simply because its likely to flow a greater mass of air thru the radiator, as the fan has much greater power behind it , you can stop most electric fans by holding a small wooden dowel in the blades , doing that with an engine driven fan results in dowel tooth picks or a busted fan blade.
(2)puller fan designs tend to be far more efficient than PUSHER DESIGNS
(3) viscus fluid clutch fans that slip under high rpm loads, but work great at lower rpms, tend to be a very effective choice, as they are more efficient at low engine speeds.
(4) ducting to control air flow thru the radiator adds a great deal to the cooling efficiency, the more air flow thru the radiator the greater the potential ability to transfer heat.
(5)larger aluminum 3 and 4 row tube design radiators can provide far more efficient cooling than typical 2 row OEM designs, because they provide much greater surface area for coolant to transfer heat to outside airflow.
(6) having your OIL / lube system and any oil coolers or larger capacity oil pans set up to maintain a high and well controlled fluid flow rate tends to help total engine and transmission cooling a great deal
(7) your ignition timing advance curve and your fuel/air ratio will effect the engines heat generated
(8) a low restriction exhaust tends to help reduce engine heat.
(9) yes they make high volume water pumps and they almost always help!
(10) a restrictive exhaust can increase engine heat
(11) if your car runs electric fans a high amp alternator in the 140-200 amp range frequently increases the fan speed and cooling efficiency
(12) running a separate oil and transmission fluid cooler with its own electrical fans tends to lower the heat load on the radiator significantly
(13)slightly retarded ignition timing, vacuum leaks or lean fuel/air ratios,low oil or coolant levels, tend to increase engine temps
some things you can do to help improve the efficiency of your cooling system:

-make sure hoses and belts are in good condition
-make sure the radiator is full of coolant
- an ANODE or two usually helps corrosion issues
- coolant additives like water wetter or purple ice tend to increase coolant heat transfer rates
- make sure the radiator and oil cooler are CLEAN and not blocked by road trash like leaves and plastic bags, paper etc.
- make sure the fan shroud actually seals to the front and back of the radiator and fan blade arc and diam. closely fits the fan shroud inner diam. (if there is a shroud in front or back of the radiator)
- make sure your antifreeze coolant is in good, in good condition and the radiators been flushed every coolant change ie acidity and coolant/water mix
- drill 6 to 8 x 11/32 holes in your thermostat, flange ,this will allow for some coolant flow with a closed thermostat.
just a point many guys seem to over look, the fans run on electricity and a higher amp capacity alternator provides a good deal more current to spin those cooling fans, Ive seen several cars with marginal cooling that had that cooling issue disappear once a 160-200 amp alternator replaced the stock alternator, the increased current allowed the cooling fans to spin a good deal faster at low engine speeds and the result was more efficient cooling.
New or rebuilt engines need time to have the parts wear in, before they run at normal temps, SOME new engines tend to run 10-15F hotter for the first few days, more horsepower generates more heat and new rings and bearings lapping in generate more heat, if your oil and coolant levels are correct , and you verified the ignition timing, is correct, and the coolant temp is running less than about 215F while driving at about 50-60 mph on the high way, with a new engine I would not be overly concerned , but remember to check transmission fluid level;s and your cooling fans function.

on the first generation small block Chevy the coolant is drawn from the lower radiator hose by the water pump, and forced into the front of the block where it travels along the cylinder walls then after all the areas filled it moves upward into the cylinder heads thru holes in the head gasket that were designed to be small enough, to slightly slow the flow upward into the heads where the coolant thats absorbed cylinder wall heat will reverse direction and travels forward into the forward , in the cylinder heads collecting more heat until it flows thru the forward intake manifold coolant ports that direct the coolant to the t-stat and from there to the upper radiator hose that allows the coolant to drain back as it flows and cools thru the radiator to the lower radiator hose to complete the cycle.
this route tends to sweep any trapped air out of the system but its not ideal because the cylinder heads produce most of the engine heat, so the route was reversed in the second generation LT1 small blocks to insure the cylinder heads operated a few degrees cooler to reduce the tendency to reach detonation heat levels
yes I know your likely to just use the 14 ga or 12 ga you have, but after you do feel the wire after the fans run for 15 minutes and youll see why I strongly suggest 10ga stranded wire on any aux fan application


look thru, and read this linked info, the links help



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just some info too think thru

the rate of coolant flow thru the radiator matters, so get an efficient high voluum water pump.

the engines state of tune effects the heat generated, vacuum leaks tend to increase heat, octane used effects the heat, your ignition timing curve effects the heat

the type of coolant and percentage of water mixed with it effects the rate heats transfered

the amount and type of oil effects the temp transfer rates, a large baffled oil pan with 7-8 qts of oil does an effective job of heat transfer

the higher the percentage of the total coolant in the system that located in the radiator the more effective the system can potentially be.

a larger oil filter, and larger capacity baffeled oil pan, tends to reduce temps due to exposing a larger surface area to the air flow

anything that reduces airflow thru the radiator reduces its efficiency, adding a fan shroud can improve fan efficiency, making sure the air passing thru the radiator is not restricted entering or exiting the radiator helps efficiency

the water pump and T-stat both effect the rate heats transfered, high flow water pumps can help

the electric fans work off a sensor and the temp they turn on at can be modified, larger or additional electrical fans can be added

on an auto trans car,the transmission fluid adds a good deal of heat to the radiator, adding a seperate ADDITIONAL trans cooler with a seperate ellectric fan,removes a good deal of the load from the radiator

oil in the engine flowing over parts absorbs and transfers heat , having a larger baffled oil pan hanging down in the airflow under the engine helps cool the engine, as will a seperate oil cooler

headers remove heat faster than stock exhaust manifolds

aftermarket aluminum radiators can be far more efficient

the dia. of the pullies your using does effect the coolant flow

running the correct T-stat can help cooling, generally the 180F-190F is the best compromize

engine oil needs to reach and stay at about 215F-240f to lube and clean correctly and burn off moisture

trans fluid I try to keep under 160F,surely below 180F ,

Ideally I try to keep engine coolant in the engine in the 190F-200F range but don,t get overly worried below 230F. BTW I run a 190F t-stat, temp ranges should be kept within these ranges or the wear and emmissions won,t give you the long engine and trans life and low emmission levels you expect , drop the coolant temps lower and you may gain a few hp but the wear tends to get worse as the fluids can,t opperate correctly, drop the oil temp below 211 F and acids can form in the oil (bad for bearings)



it takes approximately 214F-215F to burn all the moisture out of oil, that moisture comes from outside air when the engine cools and from combustion when the engines not up too temp. and can form acids and rust if it sits, if your cars driven frequently IE it seldom sits for several days at a time your unlikely to have significant moisture forming, especially if the cars garaged most of the time its not in use.
short trips seldom allow the engine to fully reach a stable temp, the state of tune,the outside temps, the amount and type of oil and the temp switch on the fans , the T-STAT, allow or prevent the oil reaching full temp,the RPMS and LOADS the engine sees effects the temps puller fans, engine driven or electric, with SHROUDS that fit close to the impeller arc do a far better job than PUSHER style fans but you can use BOTH designs to maximize results
If you drive the car frequently and seldom let it sit for days at a time AND change oil fairly regularly (3000-4500 miles between changes) you may be fine with the slightly lower temps ,especially if the cars garaged but you can easily check the condition of your engine, pull a valve cover and inspect its inside surface carefully, it should be clean, possibly stained but not have minor acid etching and there should be no sludge , build up,or chocolate milk or waxey film, if there is your engines not running hot enough or your not changing the oil,filter ETC. frequently

to raise temp install a 190F-200F T-stat, oil temp generally runs 15F-25F higher than COOLANT
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Staff member ... ooling.asp
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having the correct tool to verify the engines operational temps would be helpful ... ermometer/
Wide temperature range from -58 to 1832°F (-50 to 1000°C)
any time that your dealing with a potential temperature issue or a trouble issue where , knowing the exact temperature vs what a gauge might say, it helps to have a handy and accurate infrared temp gun handy to locate and confirm heat, levels.

replace the current T-stat with a 190F T-stat and drill (6)-(8) 3/32" holes in the flange this tends to make the temp stay far more consistent

ve had good results with a 200F T-stat with the holes drilled (READ THE LINK) but many guys select a 180F t-stat

similar to this but spaced evenly around the circumference, the small hole allow minimal coolant flow rates at all times and prevent air trapped under the t-stat, coolant temps will remain far more consistent, why this is not a factory design is beyond me. yes the small holes slow the engine temp rise rate slightly, but not much, but they do tend to keep fluctuations in the temp minimal


BTW placing the edge of the t-stat on a 2x4 and using a drill press for drilling thru the flange is far simpler/safer than trying to do that with a portable drill by hand

I generally arrange the 6-8 3/32" or 1/8" holes spread around the flange equally spaced, the t-stat still controls the MINIMUM temp to a large degree but its not as likely to cause rapid changes in temp swings as cooler water or anti-freeze is not totally trapped behind it until it opens

now IM sure some guys will say that defeats the T-stats purpose but it still works and theres a noticeable increase in coolant flow at 190F when the t-stat opens so I feel its a no lost deal
6-9 evenly spaced 1/8" holes drilled in the flange of the t-stat, will work wonders at making the cars coolant temp remain at a more constant temp, but it also tends to slow the rate the car heats up the first time a little bit ... hallenges/


Ive found (6) equally spaced 1/8" holes drilled in the 180F or 190F thermostat flange on most cars works very consistently to flow just the correct amount of coolant to maintain almost constant coolant temps



keep in mind theres dozens of different T-stat housings for clearance issues

drilling 4-6 3/32" holes spaced evenly in the t-stat flange tends to make the coolant temps more consistent, and has no effect once the engine up to temperature, I have no idea why the factory does not do so, while its true that the holes tend to slow the engines required time to reach operational temperatures its also true that it prevents air from being trapped under the thermostat and and reduces temperature swings a good deal as the t-stat opens and closes

read these links (CAREFULLY)
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Staff member
Tired of your corvette or muscle car,running hot?,
then take the time and effort to read thru ALL the linked info

as a general rule the 3 & 4 row designs tend to cool better because a higher percentage of coolant is in direct contact with the internal aluminum tubes surface and that makes transfer of the heat to the fins that dissipate the heat more efficient,and don,t forget an efficient fan and shroud are critical to cooling but not all radiator cores are even close to equal, theres a huge variation in quality and some designs are far superior
cooling fans come in a large variety of types, but the idea is too increase the flow of heat absorbing air flow over the fins of the radiator while maintaining high cooling system efficiency and engine durability and low loads on the engine. an engine driven fan is fine, the main factor in moving air is in promoting high air flow rates thru the radiator to induce efficient coolant heat transfer from the radiator fins to the air, moving thru that radiator and it sure helps having the correct design on the fan blades , the max number of fan blades you can easily fit in side the shroud and an ideal set-up the tips of the fan blades are within about 1/2" of the inside diam, of the fan shroud and the blades are located so they are centered on or at least near the rear edge of the radiator fan shroud

if you need to use a fan spacer kit to get the fan positioned forward into the fan shroud for increased efficiency
having efficient components helps



infrared thermometers are a very useful tool to track down issues with tuning, or mal functioning sensors



I,m sure quality varies wildly,with viscus clutch fan hubs but Ive found most of the viscus clutch fan hubs work reasonably well if you install a fan similar to the one pictured above

the type below also works but because the blade angle changes with resistance and rpms, but you do occasionally see pictures of that type loosing a fan blade and causing damage

tube_sizex.jpg ... uctId=2545 ... pt_id=1127 ... pt_id=1126


low temp sensor ... pt_id=1252

installation instructions

cooling is basically the process of transferring heat efficiently from its source, to the outside air flow as rapidly as possible thru the process of oil and coolant flow absorbing and transporting the heat from the hotter components to the, outside air, the faster, and more efficiently the fluids can absorb, transfer and release that heat, and the greater the surface area, and conductivity between the hot fluids, and the larger the volume of those fluids, in the heat exchange areas and the higher the speeds of the outside airflow the more likely you'll be to reduce the heat generated in the hotter areas, increasing the volume of oil and coolant in the system helps, increasing the surface area of the radiator, or adding an oil cooler or transmission cooler that adds an additional heat transfer surface to bleed off that heat to the outside air or allow the oil to release heat thru other surfaces than the radiators trans fluid cooler section will help, as will, adding a larger capacity oil pan and oil cooler, simply because the oil does much of the heat transfer from the hottest components to the coolant, so anything you can do to reduce oil temperatures tends to help. oil in the oil pan is exposed to air flowing over the oil pans outer surface and that will generally reduce its temperature, so the larger the oil pan capacity the longer the oil tends to be exposed to that cooling effect, naturally a real oil cooler with an electric fan will work even better but you can use both in tandum

Running straight water in your corvettes in theory cools the engine better, because It transfers heat more efficiently BUT...straight water acts like the acid in a battery and greatly increases corrosion,it effectively causes electrolysis and that will destroy the aluminum in the cooling system very very quickly. As electricity flows thru the block the charge travels thru the water and this allows electrons from the aluminum to be carried away with it in a chemical reaction driven by the electrical charge. The end result is an aluminum head, intake and water pump that has the water passages will be eaten thru like someone poured acid in the cooling system.....There will be pits and holes at random spots where ever there is aluminum in contact with coolant. The solution is a zinc or magnesium anode to take the abuse of the electricity much like the zinc blocks that are mounted on the hull of a ship for the same reason. There are zinc anodes that can be attached to radiator caps that drop in the radiator for those that want that extra oz of protection against electrolysis. The use of the proper mix of anti-freeze & water slows or prevents this chemical/electrical process from taking place. The only other concern is the age of the anti-freeze as that anti-freeze eventually turns acidic over time.
ALWAYS use an ANODE in the block and at least 40% antifreeze to reduce corrosion, water cools slightly better but its electric conductivity tends to allow corrosion problems that are greatly reduced with antifreeze and an anode installed


From the Manufacturer: Cool Collar Lab Test Results:

Test Results Laboratory Test

Castrol GTX 10W30 motor oil was heated to a temperature of 220 degrees F. and pumped simultaneously through two identical oil filters. One oil filter had a Cool Collar attached, the other did not. A fan was used to direct seventy degree F. ambient air over both oil filters at a velocity of fifty miles per hour. The oil exiting the filter having the Cool Collar installed indicated a h eat removal approximately equal totwo degrees per minute. Whereas the oil temperature exiting the filter without the Cool Collar showed no change. (Typically an automotive engine passes all the oil through the filter more than once per minute).

Summary: With a constant heat source applied to the oil, the temperature dropped to 202 degrees F (from 220 degrees F.) with five minutes. This translates to a 12% temperature decrease of the heat added to ambient temperature.

Liquid Cooled Automotive Engine (Road Test)

This test was an actual highway test. The car used was a late model Corvette equipped with digital readout oil temperature and coolant temperature gauges. On a 72 degree F. day, at 65 miles per hour, the oil temperature read a constant 221 degrees F. The water temperature was 195 degrees. The corvette was then pulled off the road and a Cool Collar was installed. Testing was then resumed. Within a distance of five miles the Cool Collar was responsible for lowering and maintaining the oil temperature at 203 degrees F.

Summary: Our tests again indicated a 12% approximate reduction above ambient temperature of oil heat. On similar testes, it was found that after installation of the Cool Collar the oil temperature will typically drop near to the level of the engine coolant temperature.

Air Cooled Engine (Road Test)

The test vehicle used was a 1978, 911SC Porsche, equipped with a Carrera style oil cooler. The car was driven 65 MPH on a 85 degree day for approximately 35 miles. The car was then stopped and a I.R. thermometer was used to check the temperatures at various points along the oil lines, tank and cooler. In addition, the reading on the dash temperature gauge was noted. An average temperature of 220 degrees was logged.

Testing was then resumed, with the Cool Collar installed on the oil filter, over the same coarse and speed. At the end of the 35 miles the temperatures were then checked again using the infra-red thermometer at the same points as before. The indicated temperature readings showed an average reading of 208 degrees, a reduction of 12 degrees.

Turbulent Flow Basics​

turbulent flow
In a mold cooling system Turbulent water flow is much more efficient at removing heat than laminar flow. After turbulent flow is achieved, increasing the flow rate further yields more cooling benefit, but at a declining rate compared to water flow rate. The graph of "Steel Temperature vs. Coolant Flow" illustrates this point.

Often mold operators try to maximize the flow of water through their cooling systems to ensure turbulent flow. This practice increases water pumping cost and can also limit the amount of cooling water available for cooling other molds on the same cooling system circuit. A better practice is to ensure turbulent flow and sufficient cooling by using flow meters and FCI (Fluid Characteristic Indication) Technology. In this way an efficient cooling process can be realized using the minimum pumping capacity and energy.



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Staff member
I Drilled 8 holes in my thermostat as you suggested and temp gauge remains within a 10 to 15 degree range and does not go over 190 degrees. Thanks for the great advice. I bet those 70 degree fluctuation in temperature that I had prior to doing your modification were not real good for my heads. Thanks Again!
Carolina Kid "

see having a bit of experience tends to help! glad it worked as well for you as its always worked for me!

if your finding a slime in the coolant passages of your aluminum intake on your engine, its likely the result of electrolysis

the cure requires three different changes, made to the coolant system,
the first is running a 50%/50% distilled water antifreeze mix with the newer antifreeze formulas
many guys clean the coolant passages in the manifolds and paint them with several coats of marine hull paint before installing them on a car also
Call any company that manufactures aluminum radiators and they'll tell you to use distilled water, mixed with about a 50%/50% mix of antifreeze, and they have Been doing it for years and have never had any issues. the reason is that distilled water, mixed with antifreeze,conducts electrical ions far less efficiently than water with mineral content , they also advise you install an ANODE or two as a sacrificial magnesium or zinc anode reduces corrosion, they will also tell you that if your having corrosion issues to check your engine and frame grounds as even a small electrical potential in the coolant from a defective engine electrical ground can cause electrolysis,
anyone that has run an engine in a boat will tell you that salt waters corrosive, thats because salt water is an excellent electrical conductor while distilled water is a rather poor conductor, anyone with a multi meter and a double a battery a bit of wire and a large plastic glass can test the difference in ohms resistance between the two types of water

READ THESE LINKS ... /index.htm ... rticle.htm



Radiators and heaters have undergone considerable improvement. And we have had superior antifreezes in recent years (even before the introduction of the orange organic acid type). So it seems hard to believe that so many radiators and heaters fail from inside-out corrosion and perforation. Of course, vehicles are being kept in service much longer (thank high sticker prices for that), so eventually even better systems will fail. But in addition to low antifreeze protection and depleted inhibitors, there are other specific problems that contribute to the perforation failures.

The most significant is electrolysis — the flow of stray current that gets into the coolant and flows through the radiator (even along the radiator hoses) and through the radiator core to electrical ground. Although electrolysis is a single problem, it has many possible causes.

When a radiator fails in a short amount of time/mileage, and you know the coolant was a recently installed name brand, check for electrolysis. Ground the negative lead of a digital voltmeter to the battery negative (ground) post or side terminal, then insert the positive lead into the coolant itself (making sure the tip doesn’t touch a metal neck or core of a radiator). If you get a reading of 0.3 volts or higher, that’s excessive electrolysis — bad news. Older cast-iron engines could tolerate that, but the modern engine with all its aluminum components cannot.

One of the worst cases we saw occurred in just 30 days and under 3000 miles. In that one, the problem was an auxiliary horn had been installed and grounded to the radiator support. So if a vehicle recently had an electrical accessory installed (don’t forget anti-theft alarm systems), check the grounds.

Although the most severe results occur if the part is bolted to the radiator or its support (such as a radiator fan motor), the modern electrical harness is so complex, the source could be something in the rear (remember all those sport utility vehicles and minivans with their rear HVAC systems).

What you should do is check the voltage as each electrical device is turned on. Because the radiator electric fans are a primary suspect, start with them. Just remember that many vehicles have dual fan systems, and testing just one fan isn’t enough. On the typical setup, you can trigger each fan with a jumper wire to ground the particular fan relay. The relay is wired to the power-train computer on most systems, so unplugging its connector and hot-wiring directly to the fan motor may be a safer approach. Be sure to check the coolant voltage with the engine cranking, as the starter ground circuit is another strong possibility.

If a circuit seems to be producing an unacceptably high stray voltage through the coolant, as a follow-up test, try installing a jumper wire as a second ground, to see if the voltage drops. If that works, check the existing ground and if it seems to be good (or the voltage reading doesn’t improve after cleaning and tightening the ground), make a permanent installation of a second ground wire.

Produced by the National Automotive Radiator Association (NARSA)


BTW, getting the ignition timing too retarded or f/a mix too lean and exhaust temps climb, usually resulting in burnt ignition wires or plug boots


think it through ...thats USUALLY the result of a good deal more HEAT exiting the engine in the form of HOT exhaust gasses,exiting the cylinder and entering the headers..
hot exhaust gasses result from either overly lean fuel/air ratios
a retarded ignition timing, that delays the burn of the compressed gases, and allows still burning fuel /air mix to exit the exhaust port.
cam timing that is causing very effective cylinder scavenging that allows some of the fuel/air mix to enter the headers after passing through the cylinder , as inertia drags it out following the previous exhaust gases ,before the exhaust valve closes.
very rarely miss firing injectors throwing excessive fuel
honestly a bit of basic engineering and thinking about a cause and effect relationship and a bit of testing can go a long way toward isolating a logical search for any should also be obvious that as the rpms increase so does the volume of exhaust gases and thus the heat transferred to the exhaust, at idle your more than likely seeing less than 500 pulses of hot exhaust entering the headers per minute , at 6000 rpm thats 3000 pulses of hot exhaust entering the headers per minute



the second is INSTALLING A COUPLE ANODES in the engine

the third is making sure the engines well grounded in two places to the BLOCK, not the intake, and to the cars frame and battery are all well grounded

failure to verify clearances, verify valve train geometry , provide lubrication, and maintain cooling , stay out of DETONATION,or use of inferior components or exceeding your engines valve train control limitations, or red line on rotating assembly design strength can get darn expensive




think you may have a blown head gasket or cracked heads ETC??
have you tested for a cracked head or block with the reactive dye in the coolant that shows exhaust gasses contamination?


watch this link
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oil flow, not coolant does the first heat transfer from the critical bearings,rings,rockers,springs,ETC. oil flow must remain constant and under enought pressure to always provide a film between the moving metal parts, a high capacity oil pan in the 7qt-9qt range and windage control system for the oil helps a great deal with engine cooling.
I have repeatedly said that your oil temp should keep above 215° to allow moisture to burnout of the oil and that your coolant temp should stay in the 180-220 range
SMOKEY YUNICK, in several places in several books, refers to extensive dyno testing he did for General Motors, where they consistently found, that both engine wear and hp production benefited when the oil temp stayed above 215° but below 240°, and the coolant temperature stayed between 180 and 220, degrees, or as SMOKEY said, trying keep your oil hot, but your coolant, about 20 to 30° lower in temperature but the coolant should never be below 180°, and should not exceed 220°, while temperature should never below the below 215°, and 235 to 240 is about ideal, mineral base oils tend to start breaking down over 240°, synthetic oils can easily handle temperatures up in the 270 degree range in for extended periods, but they performed best in their lubrication in cleaning function went down in the 240 range

I normally buy oil pans from these guys as they are good quality for the money

i don,t usually have alot of money to waste so I normally buy this #KEV 1090 oil pan for $100 and weld a sump extension forward
with this kit they sell for $26 # MWM 15900
and add a windage screen #MIL 32250 for $80,so for about $220-$245 you can have a baffled 9.5 qt oil pan with windage screen

while I tend to build or modify my personal oil pans
MOROSO has a good product, in several versions,



which I can recommend if your buying one!

you will need to carefully measure clearances for the cross member,suspension,headers,starter,oil filter, ground clearance, ETC. before ordering , or modifying an oil pan

restricting coolant flow speeds to help cooling is a MYTH,started when guys found that removing the thermostat could cause overheating on some cars, the thermostat did not restrict the flow significantly but it did tend to prevent the waterpump from cavitateing and failing to efficiently move coolant.
large tube aluminum radiators tend to cool very effectively

mounting an electric push fan infront of your radiator can significantly help lower temps

water wetter additive can disolve some types of paper thermostat gaskets

a 17lb radiator cap is about as high a pressure rating as you can use on a standard cooling system

air flowing over the outter surface of a road racing style, 8qt or larger extended sump oil pan removes a good amount of heat from the engine, tall valve covers can also act to radiate heat from the oil running over the inner surfaces

header coatings can also help reduce under hood temps

naca ducts or side vents that allow efficient removal of air flow behind the radiator can help cooling

YES YOU SHOULD RUN A THERMOSTAT, about 180F-190F prefered on most high performance cars


1 - Coolant does not pass through radiator freely. Over time, chemical reactions can cause corrosion buildup in the radiator tubes and can restrict the flow of coolant through the radiator. Also, debris can accumulate at the tube openings (similar to a strainer) and the resulting blockage can restrict flow. The result is that the heat is not transferred from the coolant to the fins and overheating will likely occur.

2 - Air flow is restricted through the radiator and heat cannot be dispersed into the air. If trash or bugs clog the fins on the radiator, then the air flow cannot pass over the fins and the heat is not dispersed into the air. The buildup of heat can cause overheating.

3 - Deterioration. Over time, the metal fins oxidize and deteriorate. Road salt and salty air from coastal areas contribute to speeding up the oxidation process of radiator fins.
RADIATOR CORROSION INHIBITOR Prevents overheated radiators caused by rust, scale and corrosion. Save money on needless flushing, repairs, anti-freeze changes, special additives! Zinc anode slips in radiator filler neck and neutralizes rust/corrosion-causing chemicals. Lasts for years. NOTE: Not for radiators with plastic tanks.


the more surface area and coolant volume the radiator has the more potential it has to transfer heat to outside air flow

if you don,t read the links youll miss most of the info!

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if you've ever cleaned the crap out of a corvette radiator you'll find it tends to suck crap like leaves and plastic bags and feathers up over time that block air flow, a deflector screen you can fabricate from HARDWARE CLOTH or perforated aluminum sheet, or expended aluminum, and mounted with SCREWS AND FENDER WASHERS OR TY-WRAPS will DEFLECT A HUGE PERCENTAGE OF THAT CRUD
keep in mind expanded metal


and perforated sheet metal


are generally fairly easy to trim and work with and a pattern is easily produced from poster board and masking tape so you can get a near perfect fit and something that looks decent if you want to take the time and effort,even if theres little chance the casual observer would notice,

viewtopic.php?f=62&t=1518&p=3473&hilit=preforated#p3473 ... nAodfW_s1Q ... top_cat=60 ... square.asp



"How do you know what size transmission cooler to use? " ... Code=guide

# Small compact cars, No towing Coolers with GVW ratings of 10,000 to 16,000 lbs.

Mid-size cars, Light towing
# Coolers with GVW ratings of 14,000 to 18,000 lbs.

Mid-size trucks & full size cars
Towing up to 5,000 lbs.
# Coolers with GVW ratings of [color]18,000 to 24,000[/color] lbs.(on most performance applications)
Pickup Trucks, SUV's
# Towing up to 7,500 lbs. Coolers with GVW ratings of 22,000 to 26,000 lbs.

HD Trucks, Motor homes
Towing up to 10,000 lbs.
# Coolers with GVW ratings of 22,000 to 30,000 lbs.

Super Duty trucks
Large Motor homes
# Coolers with GVW ratings of 28,000 lbs. and UP ... an-coolers

viewtopic.php?f=57&t=176 ... n-pans.htm ... p?cPath=98

viewtopic.php?f=71&t=662 ... toview=sku ... ilyid=5955 ... _Where.htm
]In many cases adding a deeper transmission pan that adds two or more quarts will lower the average transmission temp. at least 15 degrees, while its certainly not as effective as a trans cooler with an electric fan, but far better than nothing at all!, and you don,t need to run coolant lines, just be aware that if theres limited ground clearance under the car, a deeper trans pan may be a problem when speed bumps and steep driveway access is encountered
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How to Build a Killer Cooling System

OK, so now we know all the basics - what the parts are, what they do, how the system flows and is plumbed, what pressure does for us, etc. Now - what distinguishes a good, capable cooling system from a lousy, inadequate one? How do you begin to design or build a cooling system for your rig?

The quick answer is, you should maximize:

1. The flow of the coolant - the higher the better. More flow will always equal more cooling. Do this with a high-flow water pump, large hoses and passageways, large radius bends, and keeping the passageways as free of restrictions and blockages as possible.
2. The flow of air through the rad - quality, high CFM fans (like those from SPAL), properly shrouded, as well as appropriate bodywork/ducting to ensure air flows through the rad and not around it. Don't lean the rad way back, as air will flow over rather than through it.
3. The surface area of the radiator - use the biggest you can possibly fit. More details on rad tech to come shortly but again, short story is - buy an aluminum one from Griffin!
4. The percentage of water in the coolant - for cooling, as we have discussed, water is best - use as high as a percentage as you can get away with (without freezing, boiling, or corroding the system)
5. Pressure. Use the highest rated rad cap you can without blowing a hose or cracking the rad or some other component. More pressure equals higher vapour point (boiling point) which not only means less chance of steam pockets or boil-over, but also that the coolant can continue carrying away heat at temps beyond which lower pressure systems would have maxed out.
6. Turbulence. Turbulent (or rough) flow of coolant through the rad ensures that as much hot coolant as possible is exposed to the cooling surfaces of the tubes. If flow is too smooth (laminar), only a thin outer layer of coolant is cooled in the rad and an undisturbed, hot core of coolant goes uncooled. That's uncool! Griffin have some super-trick ways of ensuring turbulent flow in their high performance rads.

Here are Griffin's "10 Commandments for Maximum Cooling". I agree with them all (I'm sure they'd be relieved to hear that ;-) as they apply to most normal, street-driven vehicles. For race or other high-performance vehicles the only exceptions I would take are with regards to the the pressure of the rad cap and the percentage of Ethylene Glycol or Propylene Glycol in the coolant, as we have discussed.

1. Thou shall make room for an adequate cooling system in the design of your engine compartment.
First things first. When planning your performance vehicle, remember that you’re building it to drive, not to sit and steam. Plan adequate space for the cooling system including the radiator, fan, shroud, over flow tank and mounting brackets. Talk with a cooling specialist to help you size the system for your vehicle, engine and driving habits. Consider the investment compared to the total cost of the car.

2. Thou shall shroud thy radiator when using a fan.
Fans move air through the radiator assisting in cooling the engine. A fan without a shroud is better than no fan. But, consider this. At idle or cruising speeds, you need the entire cooling system working at its optimum. An unshrouded fan is moving air through only the portion of the radiator equal to the surface area of the fan. For example, on a ’32 Ford, the area of a 15.50” fan is about 189 sq. in.; the core of the radiator is approximately 371 sq. in. This means that almost 49% of the unshrouded radiator is not receiving any benefits of the fan. Shrouding your radiator lets the fan pull air through the entire core.

3. Thou shall use an electric fan.
Rule of thumb. Only choose a mechanical fan over an electric fan if it’s your farm tractor. An electric fan is preferred because when you need a fan the most (at idle or cruising speeds) an electric fan is delivering maximum air independent of engine RPMs. Fans that move 2000-2300 CFMs are worth the investment. Preference should be given to a “pull” vs. a “push” fan. Mounted on the engine side of the radiator, a pull fan does not interfere with air flow at highway speeds. All shrouded fans should be on the engine side of the radiator.

4. Thou shall consider airflow or how a radiator cools.
Without adequate air flow, a radiator is just a reservoir for hot water. Coolant transfers heat to the tubes; the tubes transfer heat to the fins; air moving through the fins dissipates the heat from the radiator. You need sufficient openings to the radiator that channel adequate air to the entire surface area of the radiator. You must have a radiator design that allows the air to pass effectively through the radiator (wider and taller is better than thicker). You must consider how the heat will be evacuated from the engine compartment.

5. Thou shall use the proper water pump pulley ratio.
To obtain the maximum operating efficiency rate for your water pump at highway speeds, you should overdrive the pump by 30-35%. Check your pulley selection. Most after market pulleys are a 1:1 ratio. For a 30-35% overdrive, the crank pulley should be approximately 7 7/8” and the water pump pulley approximately 5 3/4”. This overdrive provides proper coolant flow from the engine and through the radiator.

6. Thou shall consider the effects of the pressure cap.
The higher rated the pressure cap, the hotter the water has to get to boil. One pound of pressure raises the boiling temperature 3°F. A 16-pound cap raises the boiling point to 268°F. If your engine is designed to run at 200°F, a 14-16-pound cap should be sufficient. Running a higher pressure cap to prevent boil over is putting a band aid on another problem that needs to be fixed. Higher operating pressure places additional stress on the entire engine system and increases the potential of hoses bursting and possible injury.

7. Thou shall understand the operating temperatures of today’s modern engines.
All engines have “normal” operating temperatures. Running engine temperatures well above or below recommended temperatures could cause damage. Most of today’s engines operate in the 180°-210°F range. Pollution laws, new oil blends and higher combustion gasoline have forced engine design changes that have increased operating temperatures over the past decade. Consider your engine’s normal operating temperatures when selecting your radiator’s cooling capacity.

8. Thou shall always use a thermostat.
The thermostat controls engine coolant temperature. It stops the flow of coolant through the radiator until the coolant reaches the thermostat’s preset temperature. Operating your engine within its temperature parameters reduces wear, helps control emissions and turns any moisture in the crankcase to steam where it is removed by the PCV system. Select the right thermostat for your engine’s operating temperature range.

9. Thou shall protect thy cooling system with recommended coolant.
It is essential to use a premium coolant that protects the radiator, other metal parts and seals. Today’s coolants are a scientific blend that normally includes water wetter and corrosion inhibitors. Use of a coolant that contains no silicate is recommended. Silicate is an abrasive and can cause gel formation and water pump failure. A 50/50 mix of coolant and water provides the best overall cooling efficiency. Proper maintenance (regular flushing and changing of coolant) will extend the life of your system.

10. Thou shall spend thy money wisely.
If you are having cooling problems, begin by looking at the least expensive fixes first. 1) Add an electric fan. 2) Shroud your fan. 3) Check your belts and hoses. Slipping belts or collapsed hoses mean trouble. 4) Check your radiator cap. 5) Flush and refill with premium coolant. 6) Use the proper thermostat. 7) Clean the radiator of foreign materials. 8) Overdrive the water pump 20-30%. 9) Check your water pump. Should cooling problems persist, it may be time for a new performance radiator from Griffin. Call the Griffin Customer Service Department at 1-800-722-3723 for assistance in selecting the correct radiator for your requirements.
** WARNING: Improper wiring can cause electrolysis and destroy the radiator. Please make sure radiator is not used as a ground. **


Staff member ... stemBasics
read the thread and sub linked info
anodes are easy to find at larger marine supply stores and you can cut some to fit.



Cooling System Basics

A vehicle's cooling system is designed to do one thing - maintain the engine at the proper operating temperature. Note that I didn't say the purpose is just to "cool the engine". This is one of the first and most often overlooked aspects of a cooling system (which isn't helped by the name). Yes, it's possible to "overcool" an engine, and doing so can be almost as damaging as allowing it to overheat. This is because all engines are designed to operate most effectively and reliably at a certain temperature. This normal operating temperature takes into account internal clearances, oil viscosity (which varies with temperature), and combustion efficiency (which affects power, economy, and emissions). Too hot, and critical clearances are lost, oil breaks down, pre-ignition occurs, metal composition is changed, parts start to weld together and severe damage occurs. Too cold and combustion is incomplete, power production is reduced, emissions are excessive, economy suffers, and oil never reaches the proper temperature and therefore viscosity and is therefore too thick to provide proper lubrication - especially between critical surfaces like main and rod bearings.

To be fair - the majority of the work the cooling system must perform is to remove from the engine heat produced by combustion - but a good cooling system must also be designed to allow the engine to come up to proper operating temperature as quickly as possible and then keep it there.

Power makes heat. The more power the engine creates, the more heat it creates. As wonderful as they are - spark-ignition internal combustion engines are actually pretty damn inefficient beasts. A typical engine will loose more than 30% of the power it produces to heat production. That's a LOT of heat! Peak combustion chamber surface temperatures can exceed 500°F and the temperature of the combustion itself can exceed 3000°F. In fact, if you were to run an engine without a cooling system, even for only a short time, the temperatures produced could quickly melt the piston and fuse it to the cylinder. Clearly then, cooling is very important in order to keep this and other component failures from happening.

But that's not all - even in a working engine with a cooling system, well before total component melt down occurs, if the cooling system isn't up to scratch, excessive heat in and around the combustion chamber will cause pre-ignition and detonation - both of which have major negative affects on power production, efficiency, and longevity of the engine and can cause plenty of damage of their own.

The reason I'm pointing this out is two-fold: First - so you have a good appreciation for how much the cooling system does (and therefore why it's worth investing the time and money into getting it right). Secondly, so you understand that, just because your engine isn't blowing steam out the rad cap or melting pistons - doesn't mean that it's working optimally and couldn't use some improvement. Same goes for the guy down the street (or on the internet)- who's advice you're considering taking - just because he says "I just plugged the steam ports and haven't had any problems" doesn't mean his cooling system works well or that it won't cause problems down the road.


The best radiator does no good without adequate airflow. Airflow is measured in cubic feet per minute, or CFM. In your design, be sure to allow for adequate airflow at both high and low vehicle speeds. Airflow design for low speeds is fairly easy - you need one or more good quality, powerful fans and a good, complete shroud. Without a shroud you can loose as much as 50% of the CFM you would otherwise have.

Ensuring good airflow at higher speeds is more difficult, because high-speed airflow can do weird and wonderful things and you need to account for aerodynamic flow and different air pressure zones. Rather than teach a class on aerodynamics, here are some basic tips:

* Radiator location and angle is critical to ensuring good high-speed airflow. The best installation for cooling purposes is to have the rad stand straight up vertically in the airflow. Of course, this doesn't help the car's aerodynamics, visibility over the hood, aesthetics, or engine compartment packaging very much; and brings us in to conflict with the rule about using the largest rad possible. If we install a very tall rad, there often just isn't room to stand it up straight. As a result, many people lean the rad back at an angle to lower the overall height in the chassis, while still fitting a large rad. You have to be careful when doing this though - if you lean it back too far, especially if you have poor ducting of the air to the rad, air will flow up and over the rad instead of through it. When this happens, a high-pressure zone is created behind the rad, and as we know, air flows from high to low pressure, not the other way around. This is based on the same principle by which airplane wings create lift and a carburetor's venturi works. What this can mean is, at high enough speeds, the pressure behind the rad can be so much higher than the faster, low-pressure air flowing over the rad that no air is able to flow through the rad - even with the fans on. It seems strange, but physics can be a bitch that way sometimes. I personally believe that quite a few folks tend to lean the rad back way too far without understanding or testing the effects of high-speed airflow and the high pressure zone created behind the rad. If you do happen to do this - the car will overheat and nothing else you do will help. You simply have to have good flow through the rad at the speeds the vehicle will run.
* In conjunction with maximizing airflow through the radiator, your design must allow adequate engine-compartment ventilation to allow the air that flows through the rad to exit the engine compartment. Not because it is hot air and would otherwise heat up the engine (the engine's making plenty of its own heat already) - but to avoid creating a high pressure region in the engine compartment that would prevent further airflow through the radiator.
* Minimize the objects in front of the rad that block airflow. There are usually a lot of things that take up space in front of the rad - the grill, lights, winch, auxiliary coolers, etc. All of these rob the rad of its airflow. Your design should minimize the obstruction in front of the rad that block airflow.
* Depending on the fin density, a radiator has somewhere around 1/3 of its surface area as open space through which the air flows. Maximum cooling can occur when the grill or protection is such that it has no less than 1/3 open space. In other words, try to design the grill so that it doesn't add to the restriction of airflow.
* If you mount auxiliary coolers (like a power-steering cooler) in front of the rad that rely on the rad's fans to pull air through it, keep the gap between the cooler and the rad down to 1/4 - 3/8", 1/2" max, to ensure air is pulled through the cooler and not around it before entering the rad.
* Creative bodywork and ducting may be required to ensure maximum airflow through the rad. Just because it doesn't look like there's anything impeding airflow, doesn't mean that there isn't - high air pressure is the invisible killer of airflow. For example, on many production "sports" cars, the lower air dams are there not just to scrape on every curb and bump, but because they are critical in preventing an airflow-induced high-pressure zone behind the radiator that can severely impede airflow through the rad.


As previously mentioned, electric fans offer superior flow, mounting flexibility, and computer control compared to mechanical fans. Years ago, it used to be that mechanical fans offered the best performance, but today that isn't so. Mechanical fans are subject to problems with vibration due to air turbulence when run at high RPM. This can lead to premature wear on the water pump. Mechanical fans can also consume up to 20 or more horsepower. Viscous thermo-clutches used to control mechanical fans can be inconsistent and unreliable and offer no computer control. Mechanical fans are limited in the airflow they can provide at idle and slow speeds because they are turning at low RPM. Because the mechanical fan attaches to the engine and not the radiator, clearance must be maintained so that any chassis or engine-mounting flex doesn't cause the fan to eat the radiator (which is bad for cooling!). This makes shrouding a mechanical fan a more difficult and cumbersome affair that consumes valuable under-hood space.
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Staff member
Engine Cooling Tips - Enginology
Cooling For Additional Power And Durability
From the May, 2010 issue of Circle Track
By Jim McFarland

Engine Cooling Tips
As an engineering professor for more than 40 years, my father often told me that the only difference between a difficult problem and an easy one is knowing the correct answer. While that axiom can be applied to a variety of situations, it certainly rings true for our subject of discussion this month: proper cooling of a race engine.

A principle problem in using a liquid to cool internal combustion engines is the fact that coolant temperatures vary within the cooling system. This is generally the result of differences in the locations of heated areas that contribute to unequal temperatures. For example, metal surfaces nearest the combustion space and exhaust passages tend to be higher than elsewhere in an engine's cooling system. While reverse flow systems address certain aspects of temperature extremes and levels, localized "hot spots" can still contribute to detonation, lost power, and potential parts damage.

Of the problems encountered when attempting to provide engine cooling by the use of water or ethylene glycol and water (EGW), a condition can develop called "nucleate boiling." When the localized temperature of a heated internal surface in an engine exceeds the temperature of the coolant at that location, nucleate boiling of the coolant occurs at that spot, creating what we'll call "vapor pockets" at these locations. When these conditions are created, a form of thermal insulation develops at these spots that further contributes to parts damage. Such isolated conditions of boiling can (and frequently do) result in detonation and the parts-damaging effects that result. This is especially true in racing engines that produce high levels of horsepower and, consequently, place higher demands on the cooling system than in production, over-the-road powerplants.

Dennis Wells (Wells Racing Engines) recently commented about this issue on fuel-injected motors. "We frequently run into situations where certain cylinders appear to be in periodic or continuous detonation while others in the same engine are not. We've tried relating this to possible differences among intake paths (intake manifolds and cylinder heads) and have spent considerable time on the airflow bench balancing the flow from port to port. While this has helped, we still experience the detonation problem from time to time. As I understand what it means, nucleate boiling can be a major factor in preventing proper cooling of localized hot spots in an engine. The fact that we run identically calibrated injectors and still see the problem is further evidence that it's a cooling issue."

As I recall, Smokey was once engaged in trying to find ways of addressing localized hot spots by rerouting coolant flow, changing the design of coolant passages and pursuing a path that involved exploration of reverse-flow cooling. With regard to the latter, it was his contention that by introducing cooling fluids initially at a lower temperature around the combustion chamber and exhaust port areas (a benefit of providing coolant to the top portions of an engine first), a higher rate of heat transfer would occur in the areas of localized hot spots, thereby reducing the tendency toward the formation of vapor pockets (nucleate boiling) and subsequent detonation.

While Smokey encountered some coolant pressure- and system-related problems that were not (at the time) resolved, he remained convinced that the reverse flow concept would help reduce the problems of detonation. In fact, he observed this improvement even in the course of not completely solving the other problems. It remained for Jack Evans (Evans Cooling Systems) to resolve the related problems on his own, sometime after Smokey had abandoned his project. Concurrent to solving the problems Smokey encountered, Jack developed his "waterless" (non-aqueous) coolant chemical line of products sold today.

Further to the argument and in addition to conditions leading to detonation, prolonged nucleate boiling can also cause metal fatigue and ultimate parts damage in the form of mechanical failures. In particular, when the temperature gradient across a given section of metal (cylinder heads or block) is both extreme and under rapid change, structural fatigue is accelerated to the point of possible parts failure. The use of non-aqueous coolants addresses these issues in a number of ways.

Notably, this type coolant has a much higher boiling point than pure water or an EGW blend. As a result, it directly impacts an engine (particularly racing engines) in terms of how the cooling system affects nucleate boiling. Stated another way, a higher boiling point enables improved control of localized hot-spots that could otherwise develop without employing this coolant feature. A coolant displaying a higher boiling temperature discourages nucleate boiling by reducing the tendency for hot spots to develop, based on a higher level of heat absorption.

An additional benefit of a non-aqueous coolant is that less system pressure is required to maintain high-temperature control. Since such coolants exhibit higher boiling point temperatures, elevated system pressure (higher than atmospheric) typical of water-based coolants is not necessary. As an example, a version of Evans' coolant products exhibits a boiling temperature of 350 degrees F. Even in a high-output racing engine, based on its increased level of thermal conductivity, the ability of such a coolant to control engine temperature at near atmospheric pressure reduces other system problems associated with water-based coolants. It is said that "locally generated vapor" (at otherwise hot spots) is transformed back into liquid within the coolant, preventing the development of a vapor layer at the locations of high-temperature engine parts.

When you step back and examine the various aspects of high boiling point coolants, other benefits come to mind regarding related engine components. Radiator size and cooling capacity may be downsized. The possibility of dialing in slight increases in spark-ignition timing, if acceptable to the engine, is an option for additional power. The criticality of gasoline octane requirements can be reduced. Oil temperatures and the need for extreme temperature control may be decreased. And these are but a few possibilities worth considering. But the overriding point here trails back to a comment made at the outset of this column; simply knowing the answer to a problem takes it out of the "difficult" category. My father was frequently correct about a number of perspectives.


Staff member
The Big Chill: How to Avoid an Engine Meltdown

Written by David Reher

An engine has two fundamental needs: lubrication and cooling. Racers typically devote a great deal of time and money to oiling systems, devising windage trays, baffles, deflector screens, and dry-sump systems to ensure continuous lubrication. In comparison, drag race cooling systems are almost an afterthought – and that’s a grave mistake.

The results are unmistakable when an engine overtaxes its cooling system. Excessive heat does bad things to good engines – head gaskets fail, decks turn blue, valves recede and tulip, pistons seize, and aluminum alloys lose strength. Hot spots in the combustion chambers lead to preignition, which in turn leads to detonation, which initiates a chain of destruction. It’s a blessing that an overheated engine is seldom run to catastrophic failure – usually it loses so much power that the driver realizes that something is wrong and shuts it down.

Why are drag racing engines prone to meltdown? We’ve all watched NASCAR engines run 600 miles at wide-open throttle on a sweltering summer day without problems. At the Bonneville Salt Flats, land speed record racers run flat-out for miles at maximum power. And yet a dedicated drag race car probably wouldn’t last a minute under those conditions.

The answer is in the math. One gallon of gasoline contains roughly 120,000 British Thermal Units (BTU) of heating value, enough energy to raise the temperature of 1,000 pounds of water by 120 degrees. A typical internal combustion engine converts only about 25 percent of the fuel’s energy into useful work (accelerating the car). The rest is turned into waste heat or consumed by mechanical friction. Approximately 30 percent of this waste heat must be dissipated by the engine’s cooling and lubrication systems. So if a drag race engine burns one gallon of gas in the course of staging, burnout, and a quarter-mile run, potentially more than 36,000 BTUs have been dumped into a cooling system with a capacity of only a few gallons of water.

Most drag race cooling systems are utterly inadequate to dissipate such staggering heat. Drag race cars typically use tiny radiators (or sometimes no radiator at all), low-volume electric water pumps, and inefficient fans that simply can’t cope. It’s more accurate to think of these components as “cool down” systems rather than cooling systems, since their chief purpose is to reduce coolant temperature after a run.

A true cooling system would require a massive radiator, a high-volume water pump, and huge fan to balance the input and output of heat. Look at the size of the radiator that’s required to cool a 500-horsepower engine operating continuously in a diesel-powered commercial truck– it’s enormous. Even the cooling systems in passenger cars and light trucks are rarely able to keep up with the heat gain when the engine is run at continuous peak power. That’s why the temperature gauge in my Suburban quickly heads for “H” when I’m towing up a grade.

The cooling system in a typical drag race car is marginal at best, yet we want the engine to be as cold as possible to produce maximum power. The colder the engine, the less likely it is to detonate. That’s why Pro Stock racers use chillers and refrigeration systems to lower the water temperature to below 50 degrees before a run. These systems also have enough pressure to purge air pockets effectively from the system. I realize that such systems are impractical for sportsman racers, but their use illustrates the importance of keeping an engine cool and its cooling system purged of air for maximum performance.

Filling the radiator doesn’t necessarily mean that the coolant is where you want it. It’s vitally important that the water completely fill the passages around the combustion chambers. Air is a much less effective heat conductor than liquid; efficient heat transfer demands that the coolant be in constant contact with the metal. Unfortunately, the water jackets must occupy the spaces between the ports, the head bolts, and the spark plug bosses. These convoluted passages are prone to capture air pockets and bubbles that prevent the coolant from fully contacting the metal surface.

That’s why many raised runner and billet cylinder heads have bleed lines between the ports and valves. These vents allow air to escape when the engine is filled with coolant. Engines with conventional heads can benefit from installing air bleeds at the rear of the intake manifold. In fact, many aftermarket intake manifold castings incorporate bosses that simplify the installation of auxiliary coolant lines and drain cocks.

Cooling systems in dragsters present special problems. Most dragster radiators are mounted horizontally, either well above or below the engine’s coolant connections. In either installation, it takes extra effort to purge air completely from the system.

If the radiator is higher than intake manifold, install a drain cock in the back of the radiator and run an electric water pump until the air is completely purged by cracking open the drain cock. If the radiator is mounted horizontally below the intake manifold, install a drain cock in the rear of the manifold or cylinder heads to bleed the air. Even with these steps, it may still be necessary to jack up the front or the rear of the car to get all of the air out of the system.

A temperature sensor will only give an accurate reading if its probe is in contact with the coolant. If the water jacket isn’t filled completely or contains air pockets, the temperature sensor will give a false reading. The gauge may say that the engine is cool, but it could actually be overheating. It can take time to purge the air from the cooling system, but the result is well worth the effort.

Some racers use a hot engine as a band-aid for another problem. I’ve heard racers say, “The engine stumbles at the starting line, so I have to run it at 180 degrees.” In reality that is a carburetor problem that needs to be fixed rather than covered up with a hot engine.

The objective of any racing engine is to burn as much fuel as possible in the shortest amount of time. The energy that’s released is what propels the car to the finish line. The unavoidable consequence is that more heat is also released into the cooling system. Keeping this heat under control is essential to engine survival.


Staff member
More than you wanted to know about Liquid Engine Cooling

Liquid cooling is an often overlooked part of an engine's operation. If it's not overheating then everything's good. The problem is that, when trouble does develop, the answers can be elusive.

I'll come right out front by saying that I work at Evans Cooling Systems, Inc. and stand behind the properties of our waterless coolant. I'll tell you about it at the end, but first I'm going to cover some things that you should know if you choose to use a water-based anti-freeze. If you're sick of overheating, you can just skip ahead.

Pressure: A higher pressure will raise the boiling point of a liquid. A lower pressure will lower the boiling point.

Water runs down hill. For us, it's more important to recognize that vapor wants to go up. This is why cooling systems (almost) always flow out of the bottom of the radiator, down to the pump and into the bottom of the engine. Vent lines are placed so that vapor can escape (from the pump, head, or elsewhere) and go up into the radiator. This direction of coolant flow naturally carries vapor up and out of the engine.

Overheating happens when the coolant temperature reaches its failure (boiling) point. Sometimes it is said that when coolant starts spitting out, it's your warning that things are getting too hot. It's not a warning of a failure; it is the failure.

Vapor shielding: As the anti-freeze begins to boil inside the cooling jacket, it forms vapor. Soon the vapor increases from a few bubbles to being a layer along the metal surface. This layer prevents liquid from contacting the metal and the metal is effectively insulated; it is no longer “liquid cooled.” The metal temperature spikes and hot spot detonation, seizure, and other engine damage are the result. Head gasket failure is due to head warping which is the result of uneven temperatures across the head.

System Layout
There are from 6 to 9 basic components depending on the particular layout of the cooling system: radiator(s), cap, overflow tank, hoses, hose clamps, thermostat, cooling jacket (inside engine), pump, and fan. Dirt bikes will lack some of these parts and complex street bikes can have more.

Avoid Boiling the Coolant
The goal of the system is to cool the engine, but that statement is too simple. The goal is to keep the metal temperatures under control and this can only happen if the liquid is in contact with the metal and carries the heat away. It is often recognized that a greater amount of heat is removed through the action of boiling, but this is only true until the bubbles formed grow big and displace the liquid coolant. If the metal is in contact with vapor, not liquid, the metal temperature cannot be controlled. Boiling coolant is to be avoided.

There are two sides to improving the efficiency of your cooling system. One is maintenance and the other the choice of components.

Keep the outside surfaces of the radiator clean. Spray water through the fins from the back to clean out mud and grass. I never use a pressure washer on my bikes. Some teams put a mesh across the front of the radiators in muddy conditions. If the fins get bent, you can spend some time to straighten them out. Every little bit helps improve efficiency.

Check the hoses. Obviously you are looking for cracks or bulges so they can be replaced before a failure. Keep in mind that an older hose can leak through the threads. The hose may look fine, but the coolant can get through the inside layer of rubber and then follow the threads out. Leaks don't always drip to the ground; look for a crusty streak, sometimes at the pump.

Change your anti-freeze every year. After time, the corrosion inhibiting additives fall out of solution and settle out of the coolant; this is the sludge that collects at low points in the system. When this happens, the anti-freeze will continue to cool the engine as it did before, but there is much less corrosion protection. If left like this for too long, the corrosion that forms will insulate the metal surfaces from the coolant and this WILL decrease the cooling efficiency. This is why they suggest using a vinegar rinse to clean the system out.

Diagnosing an overheating engine
Radiator cap: Does the gasket seal? Any rips in it or dirt under it?Is the small disc on the underside free to move? This disc is the return valve that lets coolant back into the radiator from the overflow tank when the engine cools. If the cap doesn't pressurize the system because it doesn't seal, the boiling point of the coolant will be lowered and overheating is the result. A leak elsewhere in the system can also cause a loss of pressure; at operating temperature, you should feel the pressure if you squeeze a hose.

Thermostat: If it is stuck open, it may be hard to warm the engine up on a cold day.If it is stuck closed, the engine will run hot or overheat. You can test it by putting it in water and seeing if/when it opens as you heat it up. Thermostats have different temperature ratings. If it's a “190 thermostat” it should be open at 190F. Racers often remove the thermostat entirely to increase the flow rate of the coolant. Do not remove a bypass type thermostat unless you constrict or block the bypass line. There is a myth out there that if you remove the thermostat, the coolant will flow too quickly to shed the heat through the radiator. The radiator can dissipate heat just fine; in fact, it becomes more efficient with a greater liquid/air temperature difference. The myth originates from a real effect which is based on pressure. The thermostat (or restrictor that may be installed in its place) raises the pressure on the coolant in the engine as the pump pushes against it. This higher pressure raises the boiling point of the coolant inside the engine.

Pump: Obviously, if the pump doesn't pump, you'll overheat. These days pump impellers are likely to be plastic. We've seen manufacturing problems where the impellers separate from the shaft; you could look at this impeller and not see that it's broken, but it would come off in your hand. We've also seen the blades snap off due to cavitation. Cavitation happens when a coolant is close to its boiling point. The “draw” side of the pump naturally has a lower pressure, and this can cause the fluid to vaporize. As the blades smack against this mix of vapor and liquid, they can wear or break. The pump is not designed to pump vapor so this cavitation also slows the coolant flow which will cause the temperature to rise. If the additives in the anti-freeze have fallen out of solution or you've been using straight water without a pump lube, the pump seal can fail leading to a bearing failure. Engine oil that looks creamy is telling you that there's water in it. If it's reddish brown like peanut butter, it's rusty water.

Jetting: A lean fuel/air ratio will cause an engine to run hotter. An aftermarket pipe without proper jetting/fuel injection tuning will flow more air making the engine run leaner. A clogged jet can do the same. Changing things like cams, spark advance, and compression ratio can make an engine run hotter. Ethanol in the fuel will burn leaner. Look for a possible air leak in the boot between the carburetor and head.

Altitude: It's not just that the air is less dense at altitude, but the lowered ambient pressure also has an effect. The radiator cap will pressurize the system to, say, 13 psi *over the atmospheric pressure*. A lower atmospheric pressure will lower the internal system pressure.

You or your friends: If you are riding slowly, there is less airflow to the radiator. If you get stuck or are waiting at a bottleneck, that problem is worse.

Air Pocket: Air trapped in the system can interrupt coolant flow and cause overheating.

Optimizing the System:
Hoses: Silicone hoses are better quality in general and resist heat stress and age cracking. There are silicone hose kits available that eliminate the plastic Y connector. This connector has a smaller inside diameter than the hose, so it restricts the flow; get rid of it if you can. If you go to silicone hoses, spend a little more on the recommended hose clamps so that they don't cut into the silicone. Silicone hoses are more delicate in terms of impacts, so consider a guard in places where a rock may hit it.

Radiators: There are a number of aftermarket radiator companies that make upgraded radiators. Generally they are bigger and/or deeper which adds fluid capacity and surface area to the system, both of which help lower coolant temperature. Whatever radiators you use, make sure they're clean inside and out.

Radiator cap: A higher pressure rated cap will raise the boiling point of the coolant. Race teams sometimes take this to an extreme; I've seen auto racing teams that have an air valve on the cap so they can pressurize it with an air compressor. The FIA limited the allowed pressure in Formula One for safety reasons. I don't recommend raising the pressure more than just a few psi.

Pump: There are some aftermarket pumps available. A better impeller will increase flow and an efficiently designed housing can reduce the flow restriction.

Fan: There are fan kits available now for some dirt bikes; increasing air flow to the radiator will decrease the coolant temperature. Making sure the fan is operating correctly is important. There can be failures of the temperature sensor or fan switch. Some people like to install a manual switch so they can override the automatic operation. If there is a shroud around the fan or ducting that the manufacturer installed, make sure it remains as they intended.

Anti-Freeze: Any coolant with water in it has the same basic properties because those properties are limited by water's characteristics. Water boils at 212F at atmospheric pressure. The boiling point is raised a little when it's mixed 50/50 with glycol, either ethylene glycol or propylene glycol. The big increase in boiling point comes from pressurizing the system. Tap water is terrible stuff to use, but most of the anti-freeze for sale today is pre-mixed with clean water anyway. Many equipment manufacturers have guidelines on the anti-freeze to use such as “no phosphate or silicate based additives”. These additives can be gritty like sand and are bad for pump seals.

Limitations of Water:
Water is corrosive. Anti-freeze manufacturers use a number of different additive packages to fight this property, but they all settle out after time allowing the corrosion to occur. Some additives are bad for seals like silicates. Some additives, like the OAT type(organic acid technology) degrade silicone.

Water conducts electricity. This electrolysis eats metal. You can buy “sacrificial” metal tablets to put in the system that will “absorb” the damage from electrolysis.

Water's boiling point is too close to the operating temperature of the coolant. There is a very narrow safety margin and the anti-freeze will boil in specific locations before the system is observed to be overheating. The area around the exhaust valves is typically quite hot. When the anti-freeze boils here, a vapor layer forms that shields the metal surface from the liquid coolant. The metal temperature then spikes and detonation is the result. The engine will run poorly and lose power as the coolant temperature approaches its failure point. While the system pressure raises the boiling point, it also sets up a situation where a puncture will expel all the coolant. Hot anti-freeze will gush from an opened cap, but not because of the pressure that the cap regulates. When the cap is removed, the pressure drops which drops the boiling point in the system. It is the flash boiling that happens inside the engine that causes the gusher.

Evans Waterless Coolant:
Like I said at the top, I work at Evans, but I'm not just a paid promoter. I started using Evans waterless coolant while road racing in the 1990's when it was still legal for pavement racing. As I became more familiar with its properties, I put it in all my vehicles and started selling it at the track and online. Things grew to the point that my volume was getting noticed by the company. Years later, and here we are with a formula specifically designed for the powersports industry. I'd appreciate it if you'd let me tell you about the product that I believe should be in every performance machine out there. You wouldn't take the back off your watch and pour water in it; it's time to stop pouring water in your engine!

The high boiling point of Evans means that the coolant temperature won't go above its failure point. It operates within the same temperature range as conventional anti-freeze and is able to stay in contact with metal surfaces, even at stressful points like around the exhaust valves. Pump cavitation is avoided, as is electrolysis.

All of Evans' coolant formulas are non-corrosive and last the lifetime of the engine. If I'm rebuilding an engine, I will save the coolant and pour it back in the rebuilt engine. Evans Coolant doesn't freeze; we state that it will flow at -40F, but we have not found a freezing point. After lowering a sample to -60F without freezing, we decided to talk about its pour point like the oil industry does.

Evans Coolant is a patented blend of chemicals, most of which are commonly found in conventional anti-freeze formulas, and additives with no water. It is not a gel and will not turn gooey if anti-freeze is added to it. If something were to happen on the trail and you are forced to add water or anti-freeze, it will simply perform like conventional anti-freeze, no worse. Information on the web about poor cold weather performance of Evans Coolant refers to our oldest formula. The current formulas are approved for all weather conditions and are mandated by Rotax for use in their 900 series aircraft engines.

Evans Coolant has a high boiling point of 375F at atmospheric pressure. While it does not need pressure to raise its boiling point, we do not recommend modifying the system to hold zero pressure. It will expand 7% at operating temperature so you will notice some movement to the expansion tank, but it doesn't build pressure like water does. If you were to open the cap when hot, it shouldn't spurt out. A little might come out, like a tablespoon, but if more does, it is a sign that there is either water present or an air pocket in the system.

The added safety margin of the high boiling point will save the engine when conditions become extreme. Through an unintentional error that cut air flow to the radiator, I saw the coolant temperature on my road race bike go to 297F. The bike was still running alright, so we changed the oil and fixed the cause of the problem. The engine ran fine for all the races that weekend and then all the races at the finals at Daytona.

Evans Powersports Coolant is trusted by race teams around the world. I encourage you to go to our website to learn more and see the interview with Jay Leno or stop by our Facebook page http://www.facebook....300949013264495 for a more personal interaction. When you hear about our Chinese business, you should know that we make the coolant in Pennsylvania and export it into China. Evans China has installed American made waterless coolant into more than 150,000 new passenger cars so far!

security gates

New Member
I could use a thing or two with this post, we recently changed our old cooling system with a new one and although i got it installed by professionals, i still need basic know-how of how cooling system works.


I priced out Evans Waterless Coolant tonight on Summit Racing Grumpy.
5 Gallons required to fill the Cooling system on my 1970-1/2 Trans Am.
$250 worth of that stuff.
Not sure.
I always used 100% Distilled water & 1bottle of of Redline Water Wetter.
Come late fall drain the block & radiator for the winter.


The Ultra High compression and running true race gas & full ignition advance It stays 160 F steady.


Just thinking ahead.
I think.its going to be a Real Hot Summer.
Like we had in 2012.


The Grumpy Grease Monkey mechanical engineer.
Staff member
I've never found anything but 50%/50%,water/anti-freeze mix, and use of good electrical grounds and anodes makes the cooling system work.
first Id point out that 210-220F while above the temps your used to seeing on the older muscle cars is NOT exceptionally hot, in most modern car engines and while it certainly can be reduced its also not likely to cause you any problems if its controlled and stays under that 220f most of the time, oil should exceed 213F to boil out moisture that can cause acids in the oil to form
Id also suggest you install a long higher capacity oil filter if you have the clearance to do so, as both the extra oil capacity and the fact that the larger oil filter with its greater surface area constantly exposed to outside air flow, (especially if you have an oil filter finned cooler) can in many cases reduce oil temps 5 degrees or more



I don,t know where they sell these, finned aluminum filter covers now ,a few years back these were $20 each and significantly longer that this picture shows,
in fact they were the length of the long oil filter ,and believe it or not the combo of the longer oil filter and finned cover dropped my oil temps an additional 5 deg F , EASY TO PROVE by simply removing and replacing the slip on finned cover several times after keeping detailed records while cruising the interstate at a steady 70 mph (not a big difference but for $20 well worth it!


irtemp.jpg ... ermometer/
Wide temperature range from -58 to 1832°F (-50 to 1000°C)
don,t trust your cars temp gauges 100%, cross check oil and coolant temps with a quality accurate infrared temp gun
(1) the larger the heat transfer surface area the better the system tends to operate, but a minimum of about 1.5-2 square inches of radiator fin area exposed to effective air flow per cubic inch of displacement is generally required ,but I see places state you only need about 1 square inch of radiator surface area per cubic inch of displacement, which may be fine on a stock engine but wholly inadequate for a performance application.
be aware that head bolts enter the block coolant passages,
so if you failed to dip the bolt threads in sealant when they were assembled,
through the heads coolant can seep up along the head bolts,
into the area under the valve cover
btw read this



both of these work great at sealing head bolt threads,


(2) oil does much of the initial heat transfer in the engine, keeping the oil cooled to no more than about 15F above the coolant temp, reduces the heat load on the radiator coolant, so adding a high capacity 7-8 quart oil pan and fan equipped, remote mounted oil cooler can dramatically reduce engine operational temps.



(3) air flow rates are critical so a well designed fan shroud and a fan(s) easily capable of pulling 3000 plus cubic feet per minute in air flow is very helpful

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We Never Ever used Antifreeze & Water Mix in a Racecar.
A hose blows off or rips sudden the Racetrack is a Slippery Mess...Into the wall at full speed.

Also if headgasket blows you dont Milkshake the bearings with antifreeze.
Straight water only.

Using what has worked for me in the Past.
Going Racing.
Not DC Corvette & Do nothing at all Grumpy but Ban the Main Guy.


The Grumpy Grease Monkey mechanical engineer.
Staff member
I recently spent several hours on several different days helping one of the neighbors sons work through an issue he was having with a 1968- 69 road runner hes restoring .
(very similar to this picture I found posted else ware)

the cars basically stock, but has a 1970 dodge 440 v8 with an automatic transmission he had salvaged from a motor home and it tended to run a bit warmer than ideal as the water/coolant temps seldom went below 220F once the car warmed up fully.
we replaced the water pump, the radiator and the t-stat as the car was rebuilt.
infrared thermometers are a very useful tool to track down issues with tuning, or mal functioning sensors
infrared thermometers are a very useful tool to track down issues with tuning, or mal functioning sensors , without verified facts your guessing.
this is the most consistently accurate I.R temp gun I've used for testing[/img]
42545.jpg Extech Products
you can,t generally fix an issue until you locate the source of the problem
, so we took a 30 mile round trip to a local a local store and measured the heat of the oil pan and radiator and transmission fluid lines several times during the trip with a quality infrared temp gun, like the one pictured above.
as we found several indications that the oil and transmission fluid were running higher than ideal,temps, we ordered a few components that would reduce the heat,build -up, and increase the heat dissipation efficiency,
the engine was rebuilt but the transmission had un-known mileage , we eventually got the engine coolant temp average operating temp reduced, by installing a rather large additional transmission fluid cooler in front of the radiator, we could reduce the heat load on the radiator.
keep in mind the hot trans fluid adds considerable heat to the radiator as the lower section has the trans fluid cooler inside it.

remember oil flow over the valve train and bearing does a very significant percentage of the engines cooling and heat transfer thus it always helps to add an additional oil cooler with a powered fan, if the goal is lowering the heat load on the radiator
read these links ... Code=guide ... an-coolers

# Small compact cars, No towing Coolers with GVW ratings of 10,000 to 16,000 lbs.

Mid-size cars, Light towing
# Coolers with GVW ratings of 14,000 to 18,000 lbs.

Mid-size trucks & full size cars
Towing up to 5,000 lbs.
# Coolers with GVW ratings of 18,000 to 24,000 lbs.
Pickup Trucks, SUV's
# Towing up to 7,500 lbs. Coolers with GVW ratings of 22,000 to 26,000 lbs.

HD Trucks, Motor homes
Towing up to 10,000 lbs.
# Coolers with GVW ratings of 22,000 to 30,000 lbs.

Super Duty trucks
Large Motor homes
# Coolers with GVW ratings of 28,000 lbs. and UP

this thread has some useful info


your main issue as is almost universally the case is finding a place to mount the fluid cooler that allows air flow and reasonably easy access,
don,t forget the trans fluid or engine oil lines and fittings will need access and room for the lines,
ID strongly suggest AN#8 or 1/2" line size and a cooler with a powered fan

Ive used this several times, but its not going to easily fit most cars, so step one is finding and measuring a location to mount it



and replacing the stock 5 quart oil pan with a 7 quart baffled oil pan adds surface area, to the oil pan, for air flow under the car to cool the sump contents and the extra capacity allow about 35% more oil to be in the sump and remain there longer,at any time, then we also swapped to the longer 5.75" longer oil filter further boosting the engines oil capacity

if your cars got an automatic transmission and a higher stall speed converter its a damn good idea to install an auxiliary trans fluid cooler with an electric fan,

keep in mind most performance cars with an auto transmission and a higher rpm stall converter, will need an auxiliary trans fluid cooler, Id strongly suggest you find one with an electric fan and 1/2" or AN#8 line size as you'll want to allow a minimum of 2 gallons a minute trans fluid flow rate

its CRITICAL to keep the trans fluid clean and ideally changed about every 70K miles and use of a auxiliary cooler that keeps the fluid temp under about 170F is going to extend service life a good deal longer
Ive helped do at least 7 of these big block engine swaps now for other people and obviously results vary with the components being used but most of the swaps required a trans cooler and Ive installed 2 now in the rear tire carrier area, 200f -230f temps on trans fluid are very common on stock transmissions, with stock original engines when your beating the hell out of the trans racing, but 190f-210f on the street while cruising is more common using the stock radiator trans cooler in the lower radiator trans fluid cooler.
I had a larger than original capacity aluminum aftermarket radiator most of the time , in my corvette even with the current 383 sbc, and if I ran a 180f T-stat both the coolant and trans fluid tended to run about 190f UNTIL I swapped to a 3200 stall converter , where the temps jumped noticeably by about 20f higher, if I pushed the car ,but those temps dropped rapidly if I was just cruising in O.D. but I felt I needed a better system, to cool the trans fluid, adding the additional rear mount aux cooler drops temps to 150f-160f with the fan on and about 170f=180f with it off even if Im pushing the car so I wired a switch to the fan, and a sensor that turns the fan on at 175F ... -16759.pdf



internal cross sectional area of the fluid transfer lines matters, anything less than 1/2" or AN#8 can be restrictive to flow




Re: a transmission cooler generally increases transmission life

you need to understand how each component or adapter works,you install in any cars transmission cooling system works, on one type one passes coolant thru the adapter between the oil filter and the block to cool oil flow exiting the filter, since coolant generally runs about a minimum of 20F degrees cooler than oil temp at any point that helps cool the oil, the other way thats commonly used is an adapter that ROUTES oil to a remote oil cooler to thru lines that can use a temp controlled bye-pass valve that routes cool transmission fluid in a shorten route back to the transmission, but one the trans fluid temps exceed about 170F the valve opens and routes the hot trans fluid thru the transmission cooler to reduce the fluid temps. air fan cooled cooler with no coolant involved at all, but just outside air flow thru the remote located transmission fluid cooler, much like an oil cooler.





one of the most common mistakes less than experienced performance enthusiasts, face and very commonly over-look, is the fact that the internal cross sectional area on many hydraulic and fuel line fittings are considerably more restrictive to flow that the fuel limes or hydraulic lines inside diameter they were designed to be used with, and it varies a great deal between different manufacturers, now ideally the fittings internal passage cross sectional area is both consistent and the same or greater that the tube or hydraulic line size, it listed to match, , so a 1/2" inside diameter fuel line, or hydraulic lines?hoses, for example should have components for the connections and fittings that have significantly smaller internal cross sectional areas, it does you very little good to use lets say, AN#8 or half inch fuel lines if the internal cross sectional area of the connections and fitting used with those lines is only 3/8" or smaller in cross sectional area,this is an area where dealing with a local hydraulic supply shop that has the correct tools and fittings to custom fabricate your fuel lines, coolant or lubrication lines is a very good idea!
talk to a local professional at your local hydraulic supply, measure accurately, take the time to explain what your trying to accomplish and take several pictures to show them what your doing, and get them too fabricate any high pressure fuel or coolant lines and related fittings




Up to 45 GPH= 3/4 GPM = 5/16" or -04 AN
Up to 90 GPH = 1.5 GPM= 3/8" or -06 AN
Up to 250 GPH =4.2 GPM= 1/2" or -08 AN
nearly ideal for transmission and oil coolers :D
Up to 450 GPH =7.5 GPM= 5/8" or -10 AN
Up to 900 GPH = 15GPM 3/4"or -12 AN





but they don,t cool trans fluid or oil no where near as efficiently/fast as the larger fan equipped coolers with the AN#8 line size
and in either case finding a place to mount any cooler where you can keep it out of sight and still easily access fresh outside air flow,
is usually a problem for most people

BTW if your just looking to buy vs build a decent oil pan heres some sources

other sources"_OIL_PAN

Now the question always comes up, why do I need a high volume oil pump and 6-8 quart oil pan, the main reason youll use a high volume pump to begin with is to provide more volume of oil,at any given rpm,oil that cools the rings, rockers, bearings,that are being stressed to levels the original engineers never expected. etc,plus at high rpm levels there 2-2.5 quarts of oil in the valve covers, lifter gallery and trapped rotating with the crank assembly if you don,t have a windage screen and baffled oil pan, now hit the brakes or accelerate hard, oil stacks into one end of the oil pan and theres darn little oil left above the oil pump pickup,in a 4-5 quart oil pan,but the mods are really , only required if you have increased the oil flow rates,by increasing the bearing clearances,and re directing oil and as a result you also need to control the flow better and have more oil in the sump, ordinarily the engines needs are supplied, and the adequate volume can easily be supplied by the standard oil pump if you have not increased the clearances and done a few other mods to increase the oil flow rates to parts in the engine to increase the flow rates to cool and lubricate the components.
so the obvious question is why do you bother doing the mods in the first place, if the standard pump will work, the answer is the standard pump works fine up to the limits it was designed for, and thats a engine of about 265-327-350 cubic inches and spinning under about 6500rpm that produces under about 370hp,
once you start to exceed that theres a few modifications that can, if done correctly increase the cooling and engine durability, but those mods require a greater volume of oil flowing over parts to cool and lubricate them than the stock pump cam provide, if you read the linked info youll see that there are modifications to a, stock sbc to convert it into a race engine that are neither needed or useful on a street engine, but due to the far higher stress levels in a race engine those mods become more important to durability.
it should be rather obvious that a decent oil cooler, on your cars lube system and on your cars transmission,that keeps the transmission fluid temps in the ideal temperature range will tend to maintain the more consistent and lower oil temperature ranges both your engine and transmission will require to last under harsh operating conditions. it should be equally obvious that a well designed oil pan and windage screen that will help maintain a consistent supply of that oil to the engine and if possible a deeper aluminum transmission pan that allows you to increase the volume of transmission fluid will help maintain those consistent temps., there are several good dual path coolers available but if you've got the room two separate 6 pass coolers with 3/8" npf fittings and matching lines would be ideal.

Ive been using this recently on my transmission, as my 10 qt custom oil pan seems to provide adequate oil cooling by it self


heres a similar dual trans fluid & separate engine oil cooler


related threads


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The Grumpy Grease Monkey mechanical engineer.
Staff member
9 Rules for Improving Engine Cooling System Capability in Hi-Perf Auto
This might be a good read and/ for a Sticky for the H&C Forum Basics Root Folder/Engine Cooling.html
9 Rules for Improving Engine Cooling System Capability in High-Perf Autos
Produced by the National Automotive Radiator Association (NARSA) and by Richard F. Crook, Transpro, Inc.

- IMPROVEMENT RULE # 1 -Anything you can do to increase the coolant flow rate, within limits described, will improve heat transfer and cooling performance. Anything you do to restrict or reduce the coolant flow rate will hurt cooling performance

-IMPROVEMENT RULE #2- Anything you can do to improve airflow through the radiator core will help. Anything that blocks or slows airflow, either before or after the radiator, will hurt.

- IMPROVEMENT RULE - #3 Increasing the face area of the radiator by making the radiator larger will help. Relocating other heat exchangers that were in front of the radiator in order to expose more radiator face area to ambient cooling air will also help.

-IMPROVEMENT RULE- #4 Increasing the fin count may help, but it may hurt. Increasing the count above 16 fins per inch will almost always hurt.

-IMPROVEMENT RULE- #5 A plate fin radiator and a serpentine fin radiator of the same fin count, tube size, tube rows, face area, core depth, etc., will have the same heat transfer performance. However, serpentine fin radiators can be made with higher fin counts, sometimes resulting in improved performance.

-IMPROVEMENT RULE-#6 Louvered fins provide greatly improved heat transfer with some increase in cooling air restriction. Changing from a non-louvered radiator to a louvered radiator core almost always improves heat transfer performance.

-IMPROVEMENT RULE- #7 Adding a row of tubes may help, but it may hurt by increasing cooling air restriction and reducing the coolant flow rate in the tubes. If the cooling airflow has been increased over the original installation, adding a row or two will probably help in this situation. Increasing the number of rows beyond 4 in a louvered fin core will almost always hurt.

-IMPROVEMENT RULE- #8 Adding two rows of tubes without increasing the coolant flow rate (Bigger pump or turning the old pump faster) will probably reduce performance because of low coolant flow rate in the tubes. Reducing the tube size or going to dimple tubes may help. Increasing the coolant flow rate will surely help.

-IMPROVEMENT RULE- #9 For maximum heat transfer performance in warm climates, use water as a coolant with an additive to provide a corrosion inhibitor and water pump lubricant.For winter service, use a 50/50 water to ethylene glycol coolant solution that includes corrosion inhibitors and a pump lubricant.