Exhaust manifold to exhaust pipe connection; how to get a leak-proof connection

[Gary B.]

Mahle F7135

https://www.amazon.com/MAHLE-Origina.../dp/B007I49LQ0

Gary

[David C.]

[Jim L.]

Re: Exhaust manifold to exhaust pipe connection; how to get a leak-proof connection

Jim,

I’ll track one down. Anyone know what color originals were? Tan? Black? Gray? Not Fel-Pro blue.

How about this one: Mahle F7135

https://www.amazon.com/MAHLE-Origina.../dp/B007I49LQ0

Gary

That one on Amazon would work. I got a chuckle out of your remark about FelPro blue. Trust me, the ones sold by NAPA are not blue!

[Gary B.]

Re: Exhaust manifold to exhaust pipe connection; how to get a leak-proof connection

Dave,

just found it in the AIM: GM #3732426.

Gary

[Joe L.]

Re: Exhaust manifold to exhaust pipe connection; how to get a leak-proof connection

Dave,

just found it in the AIM: GM #3732426.

Gary

Gary------


You'll probably have to look a long time for a GM #3732426. It was discontinued in May, 1969 and replaced by GM #3946828. Both of these were an very dark gray asbestos/steel composition with a center steel shield. The 3946828 was discontinued in April, 1990 and replaced by GM #10159453. The latter was discontinued in July, 1994 and replaced by GM #12522753 which remains available from GM to this very day. It is configured very much like the original except the gasket material is a non-asbestos, tan material. Only the edge of this gasket can be barely seen when installed so I would not worry too much about color.

[Gary B.]

Re: Exhaust manifold to exhaust pipe connection; how to get a leak-proof connection

Thanks for the part number history. I figured it was asbestos originally, but of course that meant it was no longer available as such.

Gary

[Patrick H.]

Re: Exhaust manifold to exhaust pipe connection; how to get a leak-proof connection

I will tell you that from my experience, 1 out of 3 brands will actually fit correctly. Most have the holes for the studs slightly misaligned and are almost impossible to install without enlarging the holes.

When one fits, you’ll know it.
Don’t be afraid of buying 3 different ones and returning what doesn’t fit.

Given that, it never hurts to be sure the surface is flat because you do not want to go back in to replace it again. Been there, done that.

One more thought - I have had much better success with NOS GM heat risers than the current replacements sold through vendors. Less chance of warping, cracking, sticking, etc. I’ve seen all of these happen.