sealants and threads


Staff member

I can,t believe the stuff I see at the car mags that are SUPPOSED to be articles composed by guys who know what they are doing!!!!!!!
I picked up a copy of one of the more comon, chevy based magazines and theres PICTURES of a guy dipping head bolts in yellow weather strip adhesive to be used as a thread sealant on the bolt threads (its not designed to come in direct contact with oil and/or high heat coolant),and its not going to give the correct tq readings either, and on the next page the guys gooping, GOBS of clear silicone like youll use to seal aquariums or bathroom fixtures 1/4 thick on/around the intake manifold ports, NEITHER SEALANT is DESIGNED FOR or is LIKELY to perform correctly IN EITHER APPLICATION, and WHERE does this guy think all that excess silicone will go once the intakes torqued down????
theres only two high probabilitys, it will flow into the port where it will eventually harden and get sucked into the cylinders or it may hang there causing a restriction in the port, or if it flows down, it gets into the lifter gallery where its eventually going to get into the oil pump pick up screen, restricting or blocking oil flow
i would not let these guys fix a flat tire let alone work on MY ENGINES all I can do is shake my head and wonder who if ANYONE screens these articles

always use the manufacturers suggested installation instructions, as some applications or gasket types REQUIRE different lubes or sealants but heres a rough guide

head bolts #5, dip clean dry thread in

then insert and tq heads in place

head gaskets #3
main bolts #2
rod bolts #2
oil pump stud and nut #4
oil pan bolts #5
oil pan gasket #6
cam spocket bolts #4
timing cover gasket #6
timing cover bolts #1
intake bolts #1
sensor threads #5
intake gasket #6
thermostat housing bolts #5
thermostat housing gasket (also do you really need it) usually yes #6
Exhaust manifold/header bolts #1
Exhaust manifold/header gaskets #3
Water pump bolts #5
water pump gaskets #6
fuel pump #6
crank/damper bolt #1
Torque converter bolts #4
flywheel/flexplate bolts #4
bellhousing bolts #2

1 antiseize


2 oil or ARP thread lube
3 copper coat spray gasket sealer or apply dry in some cases (see manufactures suggestions)


Ive always installed head gaskets while damp on both sides with this ... B00030BFKQ

4 loctite (red or blue depends on application ,read the lables)
youll want to use the BLACK RTV oil proof sealant, pictured below on the upper surface of the oil pan gasket

6 black high temp RTV

use the correct stuff for the application, AND READ & FOLLOW THE DIRRECTIONS it prevents PROBLEMS

In any application where your tightening a nut on a stud , such as on the outer threaded ends of main cap studs or head bolt studs, youll want to use a lube on the threads that gives consistent torque reading from your torque wrench indicating the correct bolt or stud TENSION, oil and MOLY assembly lube and various thread sealants do not always do that,the end in the blocks course threads have thread sealant, the fine threads on the outer end require a totally different lubricant


a few things you should know


Ive had the best luck with the extra thick synthetic /cork composite mix gaskets ... toview=sku

[1] synthetic oil desolves that yellow 3m weatherstrip gasket adhesive than many guys use over a few months time so you cant use it to glue valve cover gaskets

[2]you must use a o2 safe gasket cement like the BLACK RTV silicone cement and you must clean and degrease the cover with acetone or a similar solvent before glueing on the gasket to get the best retention

[3]you need to allow at least a few hours to over night,depends mostly on temp. for that black silicone gasket cement to set up before installing the valve covers, and placeing them gasket side down on a table with a sheet of wax paper under them and a 20lb weight on top of each valve cover while the cement sets up is the best way to insure the gaskets stay correctly aligned on the valve covers perimeter

[4]a light coat of (PAM) cooking spray on the lower gasket surface keeps them from sticking to the cylinder heads after installation

[5] these gasket retaining rings add a great deal to the valve covers ability to firmly hold the gasket WITHOUT bending SHEET METAL VALVE COVERS OR CRACKING CAST ALUMINUM VALVE COVERS AND ARE WELL WORTH THE MINIMAL COST

[6]doing it correctly the first time saves time and money

head gaskets #3
main bolts #2
rod bolts #2
oil pump stud and nut #4
oil pan bolts #5
oil pan gasket #6
cam sprocket bolts #4
timing cover gasket #6
timing cover bolts #1
intake bolts #1
intake gasket #6
thermostat housing bolts #5
thermostat housing gasket (also do you really need it) usually yes #6
Exhaust manifold/header bolts #1
Exhaust manifold/header gaskets #3
Water pump bolts #5
water pump gaskets #6
fuel pump #6
crank/damper bolt #1
Torque converter bolts #4
flywheel/flexplate bolts #4
bellhousing bolts #2
head bolts #5
rocker stud threads into heads #5
FUEL INE ADAPTERS, and AN#8 connection threads #7

sealant to use, use the number matched to application,

1 antiseize

2 oil or ARP thread lube
3 copper coat spray gasket sealer or apply dry in some cases (see manufactures suggestions)

4 loctite (red or blue depends on application ,read the labels)
this works as a head bolt and rocker stud thread sealant, and sensor threads

don't forget the rear surface of the rear seal to block and main cap needs to be sealed, oil tight




both of these work great at sealing head bolt threads, and freeze plugs etc.

6 black high temp RTV


use the correct stuff for the application, AND READ & FOLLOW THE DIRECTIONS it prevents PROBLEMS
(7)ANY SCREW THREAD, on a FUEL LINE ADAPTER THREAD, this is one of the few sealants fuel won,t degrade


a few things you should know

Ive had the best luck with the extra thick synthetic /cork composite mix gaskets, for valve covers, the fully synthetic one piece oil pan gaskets, and perma-seal, and felpro brand on many of the other gaskets, SCE makes real nice pure copper head gaskets but that's naturally not for all applications

Stay away from 2 piece steel covers - they leak.
I'm forced to point out that proper installation and use of the proper sealants effects results, if you use the typical yellow 3m weather strip adhesive I see lots of guys use its sure to leak over time.
tcovert2.jpg ... 2_25118_-1

many guys have coolant leaks from studs and head bolts,you don,t need that P.I.T.A.IF your going to use ARP main cap studs THE TORQUE SETTINGS ARE DIFFERENT than the original BOLTS, the STUDS ARE STRONGER, BUT,you might also consider that main studs generally install after cleaning the threads in the block with a tap,blowing them dry with high pressure air, coating the studs course threads with the thread sealant and fine threads end with the ARP thread lube, when you screw them into the block the full thread depth, by hand, or with an allen hex key,then get backed out one quarter turn, the main caps or heads are installed and the nuts torqued in stages to seat and hold the main caps,or heads, now LOOK at those STUDS, the end in the block,has threads that are SAE COURSE thread, the end your torquing the nut on is SAE FINE THREAD with a much different PITCH that requires less tq to give the same clamp loads.
the bolts or threads leak IF the coolant flows up thru the threads, the path the coolant takes is exactly the same in either case, studs/bolts only LEAK when they are IMPROPERLY installed, a clean degreased thread in the block and on the stud or bolt you use then, installing either after dipping the thread section in the correct sealant, and letting the sealant start to dry on the threads for a few minutes, before installing them, prevents leaks, how the torque is applied to clamp the head has little effect.
Ive used BOTH studs and bolts on many engine builds and its proper procedure, and working with cleaned threads in both the block and fastener and use of the correct sealant on those threads not the studs or bolts that mater here.
the thread sealant stays liquid until exposed to the air, you need to allow the sealant on the threads a minute of air exposure to start to thicken before installing them,so the sealant forms a barrier to coolant flow in the threads.

guys! Ive YET to have a single stud or bolt leak!

its simple! run a tap thru the threads, test screw the clean/dry stud by hand to verify no clearance or binding then ,clean them and dry the threads on the block and studs,before you start the assembly, and just dip the total threaded surface on the lower studs course thread end of the stud that screws into the block into the correct sealant. spin it in your fingers slowly as you move the stud to the hole in the block to keep from dripping sealant on the deck,
thread it into the block full depth , back it out a 1/2 turn and let it set up for a few minutes before assembling the head gaskets and heads,but assemble the heads while the sealants still fresh/liquid, torque too spec and let the engine set for a few hours (preferably over night)


the stuff works far more relieably than most thread pastes or thread sealants, it cleans ,off fingers with a scotchbrite pad and gas or alcohol,....provided you have not let it set up on your skin very long, once its started too dry ...good luck

YES it works on BOLTS ALSO
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big2bird said:
I have to agree with Grumpy on this. I have seen many guys use silicone on intake manifold bolts. When you take a bolt out, that shit falls inside.
On another note, I have a 38 Buick I am working on. Last year, when I freshened up the engine, I had the pan off. The owner had used goobs to seal a "tweeked" oil pan. I took the time to straighten the pan, and before installation, I noticed the oil pick up screen was almost included from silicone crap.
Later, when I adjusted the rockers, I noticed no oil flow. When I removed the outside oil line that feeds them, I found it totally clogged with silicone debri. I then fixed that. I just hope that crap did not get into the journals. It has one cylinder smoking a tad, and there is little doubt in my mind the silicone did some damage.
We take all this care to be "clean room" clean during assembly, and using goobs of silicone to seal it up is contradictory to the intent.
Permatex makes thread sealant. USE IT, Not the goo. There is a proper sealant for all purposes. Use them. Cheaper in the long run.


BTW I have on several occasions seen guys who complain about various oil leaks on valve covers and rear seals ETC.
Used, engine parts will have oil embedded deeply into the micro surfaces.
almost all replacement parts will have a wax or grease preservative coating to prevent corrosion during shipping!
IF YOU simply wipe off oil soaked surfaces with a paper towel, who then smear on the sealant of there choice and proceed to install gaskets,
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

and then they wonder or maybe be in shock when you find the seeping oil leak has returned in a few weeks time!
metal surfaces may look smooth as glass but under a microscope they look like the surface of the moon , with lots of jagged surface cracks, so you really need to wash out the micro lubricants trapped in those cracks with a thin fast evaporating grease solvent and a lint free rag , followed by a second repeat of the process and in many cases a few minutes with a heat gun to dry and evaporate the solvent in the micro cracks ,
you'll generally find some rather amazing , bits of info such as temperature requirements, temperature limitations, what solvents work best to remove the cement or sealant, only after reading the directions, do you then smear the gasket sealant on both mating surfaces before bonding the two gasket & metal surfaces.(and in many cases you use a brush as dirt or oil on fingers prevents a good seal!)

chevy sb

chevy BB


383-440 mopar

318-340-360 mopar

ford 429-460

302-351 windsor ford

351 cleveland ford

352-428 ford
using anti-seize paste on bolt or stud threads helps prevent future problems

keep shop rags and solvent handy,


youll occasionally find uses for a high temp rated silicone sealant
like ultra-copper that has about twice the temp tolerance of the common black RTV


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What you need to know when you’re working on today’s engines

Next Generation Gasket Makers:

If you’ve ever replaced a water pump, dropped an oil pan, or bolted on an intake manifold, you may have used a gasket maker instead of running out to the parts store for a gasket.

Gasket makers can save you time and money, and they provide excellent sealing capabilities. But the gasket maker that was developed 20 years ago may not be best for the engine you’re working on today. Here’s why.

Engines have evolved. So have the demands on gasket makers.

Engineers have been using gaskets to seal connections between mechanical assemblies since the days of the steam engine. Gaskets were originally made of organic materials like compressed paper, cork, and rubber. But as engine technology evolved, so did gasket materials. Using RTV silicones to replace ‘cut gaskets’ became popular in the 1980s. They provided a tight, flexible, and durable seal. And if you kept them on hand, they eliminated the need to run to the auto parts store for a gasket. But since the 1980s, engine technology has continued to evolve, putting new demands on gasket makers.

To be effective in today’s engines, a gasket maker needs to:

Hold up under extreme high vibration

Modern engines work to get more power out of less displacement. Instead of the old, smooth-running, low rev V8, you get the high-frequency vibration of a free-revving 4 or 6-cylinder engine. Even V8s are running with higher vibration as carmakers and performance junkies take the horsepower arms race to new heights. The 1997 Corvette C5 Z06 put out 385 HP, and was considered a beast at the time. Today, the base model 2018 Corvette puts out 455 HP while the ZR1 delivers 638 HP. That means more stress on components and the gasket makers holding them together.

Resist higher torque loads

Just as the horsepower produced by modern engines continues to climb, so does torque. The higher twisting forces in today’s more powerful engines put an additional demand on gasket makers (and gaskets for that matter).

Hold up to higher heat

Along with all the extra power comes more heat. A classic muscle car had enough air space around the engine to fit a couple of pit bulls. All that air space helped keep things cooler. Modern engine compartments are packed tighter than a frequent flyer’s roll-on luggage. Plus, vehicle manufacturers are upping the coolant temperatures to help meet emissions standards. At one time, 160°F was a common temperature for fully warmed up coolant. Coolant in today’s higher efficiency engines typically runs at over 200°F. So, when the power comes on, that engine compartment becomes a real oven, creating another new level of stress on gaskets and gasket makers.

Stand up to modern oils and shop fluids

Gaskets and gasket makers have always had to stand up to oil and other shop fluids found under the hood. But today’s long-life oils and high-tech engine fluids use advanced additive packages to boost their service life and performance. Those additives are more aggressive towards gasket makers (and gaskets), presenting yet another challenge for traditional gasket makers.

Deliver higher flexibility

Once upon a time, the engine block and most of the components bolted onto it were iron, and they all flexed with each other nicely as temperatures and revs changed. Today’s engines mix components of radically different metallurgy, and each assembly will have it’s own rate of flex under load. In addition, performance fans are bolting on premium components that have their own unique flex behaviors. The result? To be effective in today’s applications, a gasket maker needs to be a lot more flexible, while still retaining full sealing strength.

Answering the challenge

The engineers at Permatex saw these factors developing over time and recognized the need to provide a higher level of gasket maker performance. Drawing on decades of experience in advancing sealing technology, they developed Permatex OPTIMUM Gasket Makers. Designed to deliver superior sealing capability in today’s most demanding applications, Permatex OPTIMUM GREY Gasket Maker and OPTIMUM BLACK Gasket Makers are now available to meet the challenges presented by modern engine technologies.


Specially formulated to withstand high vibration and high temperatures up to 700°F, Permatex OPTIMUM GREY Gasket Maker is a premium choice for high temperature applications and rigid joints that experience high torque loads. It was engineered for heavy-duty applications and extreme temperature conditions from -65°F to 700°F, and is ideal for newer domestic and import vehicles.

OPTIMUM GREY offers maximum vibration resistance and is 15% more flexible and has a 40% higher temperature rating than Permatex Ultra GREY. OPTIMUM GREY Gasket Maker is sensor safe, low odor, and non-corrosive.

Offering maximum vibration resistance, OPTIMUM GREY is the most advanced, high temp, maximum torque RTV silicone gasket maker available.


Specially formulated for high flexibility and maximum oil resistance, Permatex OPTIMUM BLACK Gasket Maker retains the high flexibility and maximum resistance to oil and shop fluids. It’s the optimal choice for today’s lightweight and premium components, especially where two dissimilar metals meet. OPTIMUM BLACK offers a temperature range of -65°F to 500°F and is 15% stronger and 60% more flexible than Permatex Ultra BLACK.

OPTIMUM BLACK is sensor-safe, low odor, and non-corrosive. It is resistant to auto and shop fluids and vibration. It’s one of the most advanced, high flex, maximum oil resistant RTV silicone gasket makers available.

Applications for OPTIMUM BLACK include valve covers, oil pans, oil pumps, intake manifold end seals, and timing covers.

To make OPTIMUM Gasket Makers user friendly, an extra nozzle is included to avoid nozzle clogs and deliver maximum use.

Why a gasket maker instead of a gasket?

As we noted, using a gasket maker instead of a conventional gasket can save a whole lot of time and money, and those are two reasons why pros use Permatex gasket makers and flange sealants.

Automakers use gasket makers when they build their vehicles and when a vehicle needs service, gasket makers can be used to match what was used at the factory. But most of the time, you’ll see them being used to replace a traditional gasket. Today’s gasket makers have tremendous reliability. They can eliminate leak paths that traditional gaskets can’t. And, they’re super-resistant to vibration, fluids, and temperature cycles. Plus, using a gasket maker ensures that you’ll never run into the trouble of an auto parts store not having the exact formed gasket that you need.

The full line of Permatex Gasket Makers

In addition to the new line of OPTIMUM Gasket Makers, Permatex has traditional RTV gasket makers that are specially formulated for sensor-safe applications, automatic transmissions, water pumps, and thermostats, as well as for applications that come in contact with gear oil. Permatex also offers Permatex The Right Stuff Gasket Maker. This 1-Minute Gasket Maker was specially designed for professional technicians, so that they could simply apply the gasket maker, torque, and go. Permatex The Right Stuff seals instantly, so your repair can get back into service immediately.

For more information, check out You’ll find product specs, technical data sheets, and instructional videos to help you learn more about which Permatex Gasket Maker is right for your job.
In my experience, the black rtv works ok,
but the high heat gray or copper gasket sealant has always worked a bit better

I prefer this for most of the jobs where silicone type gasket sealants get used like intake gaskets and valve cover gaskets



truthfully all three sealants work in a wide range odf applications, they work , best,if the surfaces were cleaned and de-greased prior to the sealants application,
of the sealant you select, so I doubt you,ll have any issues,
given a choice, Id have selected the high temp copper or as a back-up the high temp gray,
but like I stated I doubt any of the three would fail to do the job.
the key is proper surface, prep, de- greasing and cleaning, prior to the sealant application, and not over tightening the bolts.





On oil pans I prefer studs, and an oil pan back plate


you might want to Use with P/N 12553058 RH and P/N 12553059 LH oil pan reinforcement plates to distribute the bolt stress on the oil pan rail for 1985 and earlier oil pans P/N 14088501 (LH) and P/N 14088502 (RH).1986 and newer

rockerstudp1t.jpg - Galling.pdf

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