whats normal, am I running too hot?

grumpyvette · Jun 5, 2013

" GRUMPY? I'm having problems with my SBC 350 overheating just a little when I travel on the HIWY more than 20 miles.
Normally it would stay at 180 deg. Now it's going up to 190 deg and when I get off the expressway it goes up to 200 deg, some times 210 deg.
What is the safe operating temperature for a Chevy Small Block?

Id suggest checking your ignition advance and timing and level of coolant and oil, as a first step.
those temps are about normal here in florida, but that doesn,t mean you can,t reduce those temps if your concerned.
oil temps should generally be about 15 degrees higher than coolant temps and as long as coolant temps don,t generally exceed about 220F-230f degrees while running you'll be fine,the more efficiently you can transfer heat to the outside air flow the easier it will be to reduce engine temps.
I generally try to keep my coolant temps in the 190f range , but in slow traffic on a hot day they can and do go up.
you might want to look into adding a larger more effective fan and shroud or larger aluminum multi core radiator or auxiliary oil or trans cooler, both of which reduce the heat load on the radiator.
if your concerned adding a larger capacity oil pan, and an oil cooler can easily reduce engine temps, a salvage yard can supply an electrical fan assembly fairly cheaply.
many people find that adding a more efficient fan design or an additional electrical pusher or larger pull fan helps reduce temps. swapping to a higher capacity alternator has been shown to speed up electrical cooling fan speeds and reduce engine temps, in many cases.
(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

(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.

adding an aux oil cooler with its own electrical fan,
and ideally a transmission fluid cooler with its own electrical fan,
would significantly reduce the heat load on the radiator and engine coolant

(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

https://www.amazon.com/VIOFO-Circui...ocphy=9012039&hvtargid=pla-586493323860&psc=1

as mentioned you could use a fuse power tap,, but.. Ive generally just found a source for a switched power with a multi meter,
or tapped off the battery terminal and added a manual switch...depends on what I was trying to accomplish, Ive generally run 10 ga wire to a relay is any significant amp loads were anticipated,
and soldered in a relay and fuse as required.
https://www.summitracing.com/parts/...MI-rP_gp6F5AIVyAOGCh3PWAB_EAQYASABEgKCevD_BwE

https://www.amazon.com/PACK-AMP-Wat...DJGHS4MHT2D&psc=1&refRID=SDXCB01E5DJGHS4MHT2D

https://www.amazon.com/Ehdis-Truck-...=B01KFKEHMG&psc=1&refRID=SDXCB01E5DJGHS4MHT2D

grumpyvette · Aug 7, 2014

as always a logical isolate and test procedure is the way to proceed, you either isolate the problem to some thing generating too much heat or a failure to rapidly and effectively transfer that heat from the engine to the outside air flow,or a faulty gauge and doing that can be done thru logical testing
just because the water pumps brand new does not mean its correct for the application and I suspect its not,theres reverse rotation water pumps for serpentine belt use and you might have the wrong water pump, or the gauge not the sensors defective , obviously an infrared temp gun could be useful here, oil temps generally run 15-20 degrees hotter than coolant temps and oil temps in the 240f-250f range would be a problem.
OBVIOUSLY youll want to verify your ignition advance curve, fuel air ratio and check for exhaust and vacuum leaks, if your ignition timing is not correct it can cause over heating and if the engine builder failed to get the bearing clearances , valve train clearances or ring gaps correct, or its tuned incorrectly like its running lean or has a vacuum leak, it will run hot.
when temp sensors don,t agree then ones obviously either measuring a different area with a different temp OR the sensor or gauge is defective, to find which is true youll need to verify with a reliable third measuring tool, like a quality IR temp gun, and measure the sensors with a multi meter

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]

http://www.testequipmentdepot.com/e...1100200223789&utm_content=All Extech Products
INFRARED TEMP GUN

as always a logical isolate and test procedure is the way to proceed
http://www.harborfreight.com/non-contac ... -8905.html
viewtopic.php?f=70&t=4683

viewtopic.php?f=70&t=875

viewtopic.php?f=70&t=202

viewtopic.php?f=32&t=6550&p=20807&hilit=+propane+torch+leaks#p20807

viewtopic.php?f=57&t=149

viewtopic.php?f=50&t=10123&p=39685&hilit=head+gasket+leak#p39685
have you tested the coolant temp with an infrared temp gun, most auto parts stores have one they let you use in the parking lot to check, point it at your t-stat housing, then the water pump casting , with the engine idling, then at the oil pan, sump, write down the readings after the engines been running, and driven,around for at least 6-7 minutes so its fully up to operational temp., theres also a slim potential of a leaking head gasket , cracked head or block, so don,t assume that just because the engines a fresh rebuild its flawless, just test and isolate until you locate the cause and don,t assume a darn thing

I'd think its looking a bit more like a leaking head gasket, but ID want to do more testing, keep in mind the two exhaust ports exit in the center of the cylinder head on a chevy so that area naturally runs a bit hotter , what do the spark plugs, in all the cylinders look like ?
and Id look for coolant in the oil and get a exhaust gas test kit from napa

having An infrared temp gun in your tool box can save you a lot of time locating a problem at times

it would be normal for the area between #6 and #4 to run a bit hotter than , the area between #4 and #2, if that area runs hotter its usually an indicator of a leaking head gasket
http://www.blockchek.com/index.htm

bob · Jan 20, 2015

don,t confuse oil or transmission fluid temps with the temperature of engine coolant, Ive read all the treads I can find, Grumpy suggests that oil should be kept at about 200F-to-215F most of the time but NEEDS to occasionally exceed 215F slightly to burn off moisture, trans fluid should ideally be in the 150F-170F range so a cooler is a great idea, engine coolant should be kept about 15F-20F degs cooler than oil temps at a MINIMUM so try to get the coolant to stay under 180F- 200F

bob said:
I wanted to install a trans cooler in my car but frankly the budget would not seem to stretch to cover the cost of a decent trans cooler, that I see listed in JEGS or SUMMIT,
GRUMPY suggested we visit the local auto salvage yard to find out what was easy to disconnect and purchased used, from a larger luxury car or truck.
Or that we look around on AMAZON,CRAIGS LIST, OR EBAY.

http://www.etrailer.com/faq-about-engin ... olers.aspx

theres plenty of high dollar options
http://www.autozone.com/drivetrain/tran ... 70470_0_0/

http://www.transmissioncoolers.us/categ ... ooler.html

http://www.batinc.net/coolers.htm

http://www.transmissioncoolers.us/categ ... olers.html

but theres also some far more reasonably priced, if you look more carefully, and we found that there were several in good condition for around $50 and at that price a salvage yard will frequently include , a 12 volt fan, and duct work shield at the salvage yard.
so a hour or so spent wandering around with a few tools in a salvage yard may save you considerable cash

http://www.transmissioncoolers.us/1404.html

http://www.transmissioncoolers.us/1405.html

http://www.autozone.com/drivetrain/tran ... 38981_0_0/

http://www.jegs.com/webapp/wcs/stores/s ... uid+cooler

whats normal, am I running too hot?

grumpyvette

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grumpyvette

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bob

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