RTV Sealant

Is this a trick question? :)

None, the steel pressed intake manifold gaskets are designed to be used without any sealant, and they do the job pretty well. Just don't reuse them, they are compressed when tigthened and won't bounce back.

So.. always use new gaskets.

One of the worst things people do, is put RTV sealant everywhere. It has very little use in an aircooled VW engine.

Jan

Jan is right about RTV popping up (and out) everywhere on an engine. Ugly!

But there *is* a legitimate concern about sealing those metal gaskets (IMHO).

They worked great at the factory when the heads were shiny new and had just been machined flat and parallel and the manifold end castings too.

But in the real world, a qtr-century later, when all the surfaces have long lost their lustre and flatness, the metal gaskets often simply don't work.

Maybe the fix is to always insist on removing the heads and re-machining them to spec. and having the end castings surfaced. Or.......apply a little sealant.

I understand that in the UK they no longer even use the metal gaskets; there is some paper-based thing that seals every time.

Which sealant? Really doesn't matter; the intake part of the head never glows red.

I have used the paper type. They seal pretty well the first time you use them, but they are not reusable. They usually stick to the aluminum and tear when you take off the intake manifold. Need to use some sort of compound there to avoid sticking. On the other hand, you want them to stick, for a good seal... hmm. Then when you remove the old paper gasket, you have to remove the remains mechanically.. most people use a screwdriver to peel it off the head. Goodbye smooth, straight sealing surface :)

Also the paper gasket allows the end casting piece to bend when tightened. Bend enough so it will crack one "ear" off. The metal gasket offers more even pressure.

Anything that doesn't dry hard like glass? And doesn't react with gasoline.

I haven't had any leak problems with clean, decent surfaces and metal gaskets assembled dry. I spend some time making sure the surfaces are straight and smooth. The metal gasket is very soft, it follows the shape of the sealing surfaces pretty well when tightened. Once. :)

Jan

Jim, dont know about anyone else, but I use the metal gaskets, double sided things with squishy stuff in between.

James

That sounds like something different (an improvement). The stock gaskets that were used and that come with the gasket sets is a single layer of metal and nothing else.

You may be on to something as revolutionary as sliced bread!

I've seen those too, but haven't tried yet. Something like that anyway. Don't know where to get them.

Jan

Jim,

The stock metal gasket for the inlet manifold is a single layer of metal. But look closer at the inner edge of the ports (cicles) and you should find a narrow semi-circle of raised metal. This forms a "crush" zone for the uneven surface.

I agree with not using of RTV Sealant.

Grahame from Aus

Yes, I'm quite familiar with how the stock gasket is *supposed* to work. My point is that often when fitting up manifold ends to an old/used head, especially one which is still on the engine and can't be re-machined flat, they quite simply do not work.

Almost everyone I know has gone thru the ritual of trying to locate an elusive vacuum leak after making manifold repairs to an engine in the car. Positively frustrating...

(No disrespect intended. The gasket was a marvelous design and no doubt saved VW hundreds of man-hours on the assembly floor.)

"... but can be pompous at times and condescending."

ROFLMAO You made my day. Jim

On Tue, 5 Jul 2005 19:15:19 -0400, "Eric" scribbled this interesting note:

You've come to the right place then...no?

-- John Willis (Remove the Primes before e-mailing me)

I thought you would know :-) But was concerned others reading the post may not.

(and no disrespect taken!)

Grahame from Aus

Yeah, I try to not talk down to anyone but it's hard when you're an automotive pro like myself...

Really, I did. :-)

-- Scott