Thoughts on exhaust manifod gasket sealer?

[adam_knox]

So I have six days to get the car ready for the big day and then the move. Priority number one is the putting the exhaust manifold on. I have the gasket set, but do I put a thin layer of the red gasket sealer on it? Just trying to do this right so people don't mistake my car for a harley 10 blocks away. The gasket sealer says high heat, but never specifically states exhaust manifolds. None in the store did. Any tips from people who did it with or without? Also, if I do use it, most of the gasket sealers say skins in an hour, cures in 24. Does that mean I should keep the car parked for 24 hours? That's one full day out of service.

Thanks in advance gang!

[kencombs]

I've never used gasket sealer on an exhaust manifold. My thoughts are that the last thing you need is for the gasket to adhere tightly in this application. The manifold and block expand/contract at different rates and need to 'slide' at the joint.

Never had a leak on a good flat surface either.

[rustyzman]

As a general rule exhaust manifolds mount to the engine with just a gasket and no sealer. If both surfaces are clean and straight a good seal will be no problem. In fact, many old V8's used to come from the factory with no gasket and just head bolted to manifold. Of course after you removed a manifold, you had to gasket it to get it to seal after that.

On the occasion of dealing with a flanged mount in the exhaust that is in less than ideal condition (having to reuse pipes due to cost issues) I do seal the surface with a proper gasket and a coating of VersaChem muffler cement. In that case it works like a crazy high temp gasket sealer to fill imperfections that the gasket can't. But on your manifold, if prepped right, you should not need it.

[BeBop138]

Adam, If you are really concerned take your exhaust manifold to the machine shop and have it trued up on a planer. I did this with mine and new gaskets---no leaks:D

[adam_knox]

Hey thanks gang! I love it when there's a general consensus on a topic, don't have to worry about making the wrong choice! I scrapped all the carbon deposits off the manifold with a razor blade and cleaned it with brake parts cleaner. Looks pretty smooth. If I get a leak I'll be sure to get it machined. Hopefully I'll have the car back on the road tomorrow! (Of course now that I said that I'm sure I'll hit a hiccup!)

Thanks again for the advice and explanations!

[randroid]

Adam,

Not to stray too far from any chunk of middle ground, I use metallic gasket stuff on the manifolds and manifold bolts but not as a sealant; I use it as a lubricant so that next time it gets taken apart I don't need to do a lot of scraping nor do I twist-off many studs. Just a thought.

-Randy

[TodFitch]

Put a straight edge on that exhaust manifold. Or do a trial fit against the block with no gasket and look for gaps. I had a real problem getting my exhaust manifold gasket to be leak free until I figured out that it had warped. Taking the manifold to a machine shop and having it ground flat fixed the issue.

I agree that the gasket should be used "dry" (no sealer).