Thread: Repair an Exhaust Manifold

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Has anyone ever tried to fix a cracked exhaust manifold with Permatex? They make a specialized product just for this purpose and they claim it even works. Permatex has a good reputation. Anybody ever been there and done that? Any tips to pass along?

George Leonard

I had a 1969 Pontiac exhaust manifold that was broke in half . I had it welded . That manifold never leaked or broke again . To weld that manifold you will need cast iron welding rod .

How big of crack are you talking about? I've used it on a flathead engine with a very small crack on the exhaust flange and it worked OK. Don't know how long it lasted as I sold it but it's suspose to be good to 2000 degrees, but if it's a larger crack I do what Tango says.

i use the weld mold 700 rod it is 99 nickel rods .this is what i used many times .i have welded ex manifolds and other iron parts with this rod

The cracks (there are two) could be characterized as "hair line", but they are long. I have an extra exhaust manifold but I was just wondering if anyone had tried this stuff and whether or not it works. It would certainly be a lot easier since I think I will need to remove the intake manifold at the same time and, of course, there is a coolant connection between the two manifolds. Then there is the issue to finding the gaskets and the potential of breaking something else while doing the job-which almost always happens. The time and expense to try the Permatex solution would be negligible but on the other hand I dont want to waste my time either. Im just asking to see if anyone else had any experience they wouldnt mind sharing.

George Leonard