Hey all! Back with the same problem, another leak. Replaced full exhaust system, all new gaskets, bolts, etc... Today I happen to have the leak coming from the pass side manifold to the y-pipe. Bolts are cranked down as tight as they can go, and it still pours out. Any ideas on how to beat this? Apparently the donut gasket is not doing it's job, but the drive side is going great. Appreciate any advice!

Thanks everyone!

 

coat the donout with antiseize, as the ex warmns up the antisieze will start to boil and smoke a lil eventually it will dry out into a paste and seal the leak.

we use this trick on 460 ford motors, instea dof using gaskets on the manifolds to the heads we use antisieze on the manifold to head surface and they seal up everytime



or u can coat the donut with copper seal , install it let it dry for 3-4 hours then start the car up

 

I've found the position of the donuts to be VERY sensitive... I mean, if it's so little as 1/16" off of where it's supposed to sit against the manifold, it will leak.

I've tried the copper RTV all around the donuts... Doesn't work. Put it in the pipe flange (yes, after cleaning the flange), bolted it in, and let it sit overnight, and it still leaked. Tried it all around the flange and the outer surface of the donut where it sits against the manifold... Same thing. Same for around the cat slip joint and flange as well. Never did get those leaks to go away. Now I'm not going to worry about it because everything's going to be welded from the engine back (no, not the headers to the engine!).

I may try the anti-seize thing in the future, if the headers leak .