[78w72]

Originally Posted by JSchmitz

I drew the same conclusion on my own. Had those junk rubber rear pan seals split and leak. Use cork seal and Ultra Black and it will never leak a drop.

i never had a 3 prong one, used the 5 prong later style on 3 engines that didnt leak... but that older 3 prong one was terrible & not even a professional shop could make it seal, their attempt leaked twice as bad as my initial attempt. finally found the cork gasket procedure & its worked great.

[JSchmitz]

Originally Posted by 78w72

i never had a 3 prong one, used the 5 prong later style on 3 engines that didnt leak... but that older 3 prong one was terrible & not even a professional shop could make it seal, their attempt leaked twice as bad as my initial attempt. finally found the cork gasket procedure & its worked great.

Yep. I'm not sure if it was the material that was bad or if my pan compressed it too much. But it would split terribly.

[78w72]

Originally Posted by JSchmitz

Yep. I'm not sure if it was the material that was bad or if my pan compressed it too much. But it would split terribly.

mine didnt split it actually rolled the bead & leaked, looked like a rear main seal leak since it was way up there by the rear main, took awhile to identify it. the shop actually tried replacing the rear main too when it wasnt the problem.

[JSchmitz]

Originally Posted by 78w72

mine didnt split it actually rolled the bead & leaked, looked like a rear main seal leak since it was way up there by the rear main, took awhile to identify it. the shop actually tried replacing the rear main too when it wasnt the problem.

You can usually clean it off with brake cleaner and jack the front of the car up nice and high to find it. If ya run it, it gets all over.

[78w72]

Originally Posted by JSchmitz

You can usually clean it off with brake cleaner and jack the front of the car up nice and high to find it. If ya run it, it gets all over.

yep i dis clean it off after the shop replaced it & the rear main but still leaked. i was able to confirm it was the rear pan gasket leaking & the cork gasket & ultra black sealed it up great.

[Ram Air IV Jack]

Originally Posted by Schurkey

NOT RTV SILICONE.

RTV Silicone is for REPLACING a gasket, (used instead of a gasket) not for application onto a gasket.

There's a dozen perfectly-good gasket sealers, including but not limited to Gasgacinch, High Tack, Copper Coat, Indian Head, Permatex #1, #2, and #3. Hylomar is top-shelf, but very expensive.

"Best"? I don't know. I don't really care. Any of the ones I've listed--and others as well--are entirely adequate. When it's my money, I lean toward Gasgacinch. In the applications that I've actually used 'em on, Gasgacinch does everything Hylomar does, at 1/10 the price. There may be other applications where Hylomar is required--aerospace, for example.

RTV is used all the time on gaskets in various applications. I've personally used Ultra Blue on water pump and timing chain gaskets and Ultra Copper on exhaust manifold gaskets. Great stuff and never an issue!! Stuff says flexible which is a real plus!! To each his own!!!

[Murf]

I thought Indian Head shellac was required.


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[gtokid1968]

I use Ultra Blue at home and work for Big vacuum pumps and roots style blowers.
Seems like a GM service tech told me it was oxygen sensor safe?
One thing I always do is take a flat bastard file to ever flat surface, if it is flat it won't hurt a thing. Little burs are slight warpage from years over tightening can be filed back smooth with no problem.
I do use ultra black often seems to work just as good.

[Schurkey]

Originally Posted by Ram Air IV Jack

RTV is used all the time on gaskets in various applications. I've personally used Ultra Blue on water pump and timing chain gaskets and Ultra Copper on exhaust manifold gaskets. Great stuff and never an issue!! Stuff says flexible which is a real plus!! To each his own!!!

Yeah, I used to use RTV on gaskets. I thought it worked great...








...And then I started using REAL gasket sealer, and saw how much better it worked.

The gaskets don't squeeze out when the fasteners are tightened, the cleanup when the gaskets are replaced later is easier. And you don't have blue--red--copper--black shiit oozing out from around all the gasketed joints.

I see a lot of gaskets stuck down with "Yellow Death", typically 3M Weatherstrip Adhesive but there's other brands of the same stuff, and some guys use "Black Death", same thing, different color. I'll never use that stuff on a gasket again, either. Sticks the gasket really nice. Cleanup the next time is a total bitch.

[69ARROWHEAD]

I just replaced mine with this new style gasket. Works great, no messy sealer needed.

[Gator67]

Which Hylomar product are folks using?

[dataway]

Originally Posted by 69ARROWHEAD

I just replaced mine with this new style gasket. Works great, no messy sealer needed.

I wish more of these types of modern gaskets were available for vintage stuff. They work tremendously. A bit pricey, but often can be used again and again. Reminds me of modern motorcycle gaskets ... they just plain don't leak. It's a safety issue on a bike, not to mention the exposed engines don't market well if they are covered in leaks.

[chrisp]

Originally Posted by 69ARROWHEAD

I just replaced mine with this new style gasket. Works great, no messy sealer needed.

That is for Chevy , similar but not proper . Most use the Chevy gasket & cry about leaks , use the proper Pontiac gasket & have no leaks.

[P@blo]

Originally Posted by chrisp

That is for Chevy , similar but not proper . Most use the Chevy gasket & cry about leaks , use the proper Pontiac gasket & have no leaks.

Does the original Pontiac thermostat gasket have regular bolt holes not the elongated style?

[78w72]

& another option for t-stat housings if you dont care about originality is the aftermarket rubber O-ring housings. some may frown on them but i am using 2 of them on my cars with no issues & have reused them multiple times, zero leaks. very easy when you need to remove them & no clean up.

one is in use for over 10 years & the other has been removed at least 5 times in the last 5-6 years for different reasons. i originally used one back in the 90's for 10+ years on a 455. & if by chance they start to leak, you just buy a new $2 O-ring. surface does need to be smooth & no pitting though for a good seal.

as for the gaskets squeezing out with RTV thing, when used as a dressing & follow the directions on the tube, i have never had a gasket squeeze out or move at all. the ultra black/grey says to tighten the bolts only snug then let sit for an hour or so to set up... then torque to spec. no movement & very hard to see anything oozing out if you use the right amount. & on a pontiac blue engine you dont really see the blue stuff, or in my case on a black with aluminum parts engine you dont see the black or grey.

[78w72]

Originally Posted by P@blo

Does the original Pontiac thermostat gasket have regular bolt holes not the elongated style?

yes regular bolt holes, at least for 70's housings.

[chrisp]

Originally Posted by P@blo

Does the original Pontiac thermostat gasket have regular bolt holes not the elongated style?

Yes the original style does not have elongated bolt holes & is available aftermarket.

[krisr]

I just bought a CSR swivel t-stat housing and it came with an o-ring. I just used that and it's leak free. Prior to that, ultra grey or blue was my weapon of choice.