wet vs dry gaskets

[Tmoose]

From time to time I've heard stories that once an under-torqued gasket leaks ATF it will continue to leak. Similarly that using some kinds of sealer reduce a gasket's ability to seal because tje gasket becomes slippery, and will squirt out of the joint under pressure.

Lots of gaskets say "no sealer" >>necessary<<, but if I'm dealing with a crummy surface and the gasket has no coating of its own I don't hesitate to put a nice thin film of Permatex Super gray silicon on the surface. So far I've had excellent results on oil pans, etc, which are essentially zero pressure applications, but I'm also much more skilled at surface preparation than I used to be.

Any folks with lots of first hand experience?

 

[MikeHalloran]

I used RTV silicone on everything for a long time, until I discovered that goobers of it will jam an oil pump relief valve closed, causing the engine to inflate the filter and pump the oil out. Now I use it very sparingly, where specified.

I'm enamored of the Permatex Spray-A-Gasket, that goes on like thick red lacquer, and seems to seal pretty well. I've never trusted paper gaskets alone.

For head gaskets, I mostly follow the instructions.







Mike Halloran
Pembroke Pines, FL, USA

 

[Fabrico]

Ass-u-ming the ATF is in an automatic transmission, very nearly any factory workshop manual or training course will tell you to soak gaskets destined for these in ATF before installation. Usually 10-15 minutes. And it does not matter whether the gasket is cork or fiber. They will also tell you not to use silicone. I have followed that and run a sizable truck and equipment fleet that way for decades with great success.

For engines, transmissions, etc, gaskets such as many from Caterpillar have sealer built into them and work better when installed dry. But that goes on an expensive piece of equipment that can take several days of work to replace if it leaks.

This, no doubt, is an almost endless subject and everyone will have their opinion. But a big part of it boils down to manufacturing costs. Most automakers make very good gaskets but except for perhaps head gaskets, they are not high-tech, self sealing, no expense spared, items. Most standard gaskets need sealers.

Surface preparation is important. Surface preservation is even more important. This can be highly affected by what the last guy used on the gaskets. As Pat mentioned, follow the instructions.

 

[patprimmer]

Silicon rubber can attack some gasket materials, so should be used with caution for this reason and the reasons stated by Mike.



Regards

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[evelrod]

I've done my on maintenance on automatic trans for a long time...I NEVER use sealants of ANY kind. I seldom have leaks, in fact, I don't even recall the last time I did one that leaked. Make sure the gasket surface is flat and not scarred up and the the gasket actually 'fits'...

I've reached a point where I seldom use RTV on critical joints...too many problems. I still use the "Yamabond" type ll04 sealant on metal to metal joints that I choose not to use a gasket on. Kinda expensive, but worth the extra cost and effort...

Rod