I've had a few fixes made to my truck (2000 D2) over the last few months: (1) cylinder head gasket job, (2) new O2 sensors. Somewhere in the process, the truck seems to have started making a 'blowing noise' when hot. The noise sounds like what I would expect from a tail pipe leak, but I've look it over and felt for air and I can't see any obvious leaks on the exhaust or around the O2s.

The truck seems to run fine and the 'blowing noise' isn't perceivable when cold or at initial start up.

Any ideas where to look or a better way to find the leak?

 

Take your "TRUNK" back to the shop that did your head gaskets and have them fix the leak.

 

Oops. sorry for the typo.

I did take it back to the shop and asked about the noise but they claim that they looked around and couldn't find anything/didn't notice the noise.

Any suggestions where to look to get them to fix it? Do you think that the cylinder head is blowing? Wouldn't there be an oil leak if that were the problem?

 

You may have a bad head gasket or exhaust manifold gaskets.

 

Okay, I've found the problem. After listening around the car with a pipe to locate the blowing noise, I found that the front part (front face and lip) of the left/driver's catalytic convert is separating from the main body (cylindrical) section of the converter.

So this leaves me with a few questions:
- can a leak at the front of the cat cause any problems? The car runs fine apart from the blowing nose?
- can I just put on some of that exhaust repair goop to fix it or does the cat get too hot for that?
- I've seen that the cats come together as an expensive y-pipe. Any suggestions for cheaper alternatives?

 

You can buy "universal" cats and have your local muffler shop weld them in. You will want to replace them both at the same time.