I keep getting a leak on my passenger side exhaust at the header collector flange. When I got the truck, it had a stainless composite gasket (flat, 3", 3 bolt). I have replaced it with a copper gasket twice and then a new stainless composite gasket. The leak keeps coming back in the same spot. I ordered a Remflex gasket to try, but learned about donut gaskets earlier today. Is a flat gasket the way to go, or is a donut? If the Remflex doesn't work, I'll need to try something else. The mating flanges are a little chewed up in areas, and the union is in an awful place to work on. It's crammed up near the frame, tucked near the beam. Replacing the gasket equates to bruised knuckles and frustration!

Thanks for any advice.

J.

 

Using some high temp silicone might take care of your problem.

 

Thanks, moejr! Remflex gaskets fixed the problem. I think the issue is the pipes have unnecessarily thin flanges and are a bit chewed up in places. Pair that with the fact that most "3-inch" collector gaskets actually have close to 3.1-inch openings, and there is little margin for error.

I tried the highly rated "copper" gaskets and the composite "with stainless fire ring" gaskets off Amazon. I didn't like either. As shown below, the Remflex gaskets are much thicker and meant to crush/compress to form a seal. I screwed up the first one by not having everything perfectly aligned when I tightened the bolts. You only get one shot. I was more precise the 2nd time, and it sealed the leak. I can't speak for longevity, but we'll see!


Gaskets I tried - copper, stainless composite, and Remflex (top to bottom)




The Remflex gasket (bottom) is much thicker and meant to crush up to 50% to seal flange imperfections and conform to the mating pipes.

 

Glad the new gaskets worked out for ya!