yz250f49

Has anybody ever had an exhaust leak emanate from the beveled flange joint where the end of the header pipe pictured below, mates to the front part of the cat converter pipe?

I started hearing the exhaust leaking under acceleration yesterday on the way home, and the fumes were coming inside the car.

I'm told there is not a flange gasket on these, only the beveled fit to prevent leaking.

Have not been able to take it apart yet.

Is it even possible for these to come loose and leak, and has anyone here ever experienced this problem?

2004 3.9 V-6 @ 160,000 miles.

Thanks!

sparkchaser36

Hopefully by now you have found and resolved your leak. I just bought my wife a 2004 3.9 40th Anniversary edition. It developed an exhaust leak about 2 weeks after we got it. I jacked up the car and discovered a crack in the passenger side header right at the CAT. I removed the exhaust assembly and took it to a local welder. He immediately knew it was off of a Mustang. He said he had welded up a couple of them. I think I read somewhere that motor mounts were a culprit, but i can not verify that.

yz250f49

Yes I did, thanks. Took it to my Mustang mechanic and he knew exactly what it was. Seems to be a common problem.
Didn't have time to tear it apart myself since I needed to go to work the next day so he pulled it apart and welded it for me.
Thanks for the reply!

Florida34669

So common a problem that Ford has issues a TSB on the subject; unfortunately it's not a recall item and it should have been. I am not sure how long it takes persay for the hole to form but my recently purchased 2001 Ford Mustang 3.8 has this issue as well. Will probably let Ford or a muffler shop repair it. Hopefully it didn't destroy the CAT as well in my case.

If you take it to the dealership, mention this TSB; they will know what you're talking about easily. Good luck!

TSB 04-21-6

11/01/04

EXHAUST LEAK - CRACKED OR SEPARATED RIGHT
SIDE EXHAUST PIPE - 3.8L AND 3.9L ENGINES

FORD:
1999-2004 Mustang

This article supersedes TSB 04-10-03 to update the service procedure.

ISSUE
Some 1999-2004 Mustang LX vehicles, equipped with a 3.8L or 3.9L engine may exhibit an exhaust leak. This may be due to a cracked or fractured right side exhaust pipe, just forward of the first catalytic converter. This crack may be due to condensation dripping onto the pipe.

ACTION
To service, order and install the appropriate Service Kit based on transmission type. The Kit contains a new inlet pipe, condensation shield and exhaust hanger.