hwks1

250k miles on the car and runs good but - Car was making noise in the exhaust - like a hole in a muffler.

From underneath it sounded like it was coming from the passenger flex pipe which was pretty corroded.

Since the CAT was bad, I replaced the entire front exhaust pipe with CAT.

After reassembly, the noise was worse and now sounded like a broken or open exhaust manifold. No noise in the downstream exhaust and nothing from the driver side.. just the passenger manifold area.

Pulled the head with the exhaust manifold... no cracks or holes in the manifold? Manifold gasket is intact. The manifold donut and flange gasket looks fine too.

Now what? Where is the (pretty loud) exhaust leak coming from? Car was running well before I pulled the head. Will be very frustrating to put it back together and still have the exhaust leak.

Any ideas?

redbullgotwings

maybe its really coming from the other side of the motor?
maybe your turbo is cracked or that gasket is bad?
maybe its a unicorn jumping around in there?

pr0xZen

If its that loud as you suggest, blow smoke along the exhaust, from front to back. Should be a strong draft around your leak.