Fixing Header Leak
Fixing Header Leak See pic........my mac mids have a small leak at the #1 cylinder. This is a individual flange and primary that attaches by a slip fit that also leaks!! Can i double up on the gaskets for extra gasket thickness?? Its obvious that the mating surface is slightly warped, all header bolts are tight! Any ideas? Some high temp rtv?? These are Percy's aluminum seal for good gaskets.
The problem with copper or aluminum gaskets is they aren't designed to stop leaks any better than a paper gasket. Actually they are worse. When you use a metal gasket there is less margin for error for the flange and header to be true for it to not leak. The only advantage is they are more durable, and can be reused if not damaged. Don't try and use sealant. It will eventually blow out. If you haven't tried a Fel-Pro, the 1406 is a great header gasket. Tighten the headers from the inside out. After a few heat cycles retorque the header bolts from the inside out and see what happens. If it leaks again then you need to pull the header out and see if you can get the flange trued up. As far as the slip fit, mine leaks too and always has. If you have an extra set of heads, bolt one up (using a header gasket) and get it welded up.
