Permatex on replacement seals?

[spelunkerd]

I’ve been hearing conflicting opinions regarding whether to put Permatex or other silicone sealer on the outside of replacement seals when they are installed. Some argue that replacement seals with colored outer surfaces already have a solid sealer painted on, so you shouldn’t have to put any more on. And they say that extra silicone makes it harder for the next guy who has to replace the seal.

Others argue it is ‘insurance’, reducing the chance of premature seal failure by helping to hold the seal in place and helping to reduce the chance of fluid tracking along the metal contact surface. The latter might have been marred a little by seal removal tools when the old seal was removed.

I’m asking for an opinion poll of what you guys do….

Topic

[W00DBar0n]

I say it depends on what type of seal we are talking about. Most cases i say i wouldn’t use it.

[outdoorsman310]

i feel like it isn’t necessary. only changed one seal and the new seal had paint stuff on the outside but the old seal was plain metal. i think spring tension holds it in place and should seal it unless there is damage to the mating surface.

[Matt]

This should be an interesting debate. I tend to use a sealer when it’s just a crappy paper gasket like on a thermostat housing, but if it’s a seal that’s treated as you said, I’ll leave it be. Another thing I take into account is how big of a pain it will be to get to if the seal starts leaking shortly after the job is done. If it’s something I really don’t want to dig into again, I’ll add a thin coating for insurance purposes. I think this is equivalent to the Ford v. Chevy debate though, as you’ll have varied opinions across the board.

[EricTheCarGuy]

This is probably one of my biggest pet peves. When I was in school we had a rep from FelPro come and visit us (this was back when FelPro was still cool). The thing he kept hammering at us with was about the use of RTV. Gasket and seal makers spend a great deal of time making sure their gaskets do their job all on their own, adding sealant can actually CAUSE a leak rather than sealing one. In addition I can say that after working as a professional technician for more than 10 years one of the biggest clues to hack work is seeing RTV gooped everywhere there’s a gasket, when I would see that I knew I was in for trouble not to mention the amount of extra time it takes to clean all that crap up. Using RTV in this manner makes you a hack plane and simple in my book.

Yes there are times where sealant is required. If it is however it’s not much (you’re not frosting a cake) and it’s not applied to the entire gasket, just certain locations.

In summary please don’t use RTV unless it’s called for by the manufacturer and use it sparingly when you do, otherwise you’re just making a mess for a professional to clean up later.

[Author]

Replies