This weekend’s project was to build a new exhaust for my 944. I removed all the old, busted stuff and installed a new (aftermarket) header, and cut/fit/welded a new exhaust from scratch. I’ve done exhaust repairs before but this was my first full system. It was really rewarding and mostly fun, and my 944 sounds really nice now.

This is what I started with (new next to old):

It ended up being 15 pounds lighter than stock, and as I said before, it sounds great. BUT, the failure that is mixed in is that there is an audible leak from the header. I used new gaskets and torqued to spec, but I can hear and feel a leak from the header. I have read a few accounts of people installing new headers and having leaks that resolved themselves after a few heat cycles and re-torquing the manifold nuts. That’s what I am going to try first, I guess, since removing the header is kind of a PITA.

Has anyone run into this issue before? Is it something that can “go away” on its own with some time? I’m not super thrilled about driving the car with an exhaust leak, but I figure a few short trips just to bring the head/header up to temp can’t really hurt.