touareg

Long story short, I have an aftermarket cat welded to a bypass pipe, modified to accommodate the cat. Was done that way because a state required it for emissions.

My state doesn't require it, but I wanted to put a stock cat back in. About 1.5 years ago I purchase a used cat from a member here, looked good but did not closely inspect.

I brought it to my mechanic, and before he installed it he noticed soot around the pipe and the cat, and said it was cracked there. It was also cracked at the o2 sensor bung hole.

Is this common on these stock cats, and does just doing a weld there fix the problem (plugging the leak), or will it just crack again if not taken apart and re-done.

Thanks!

RajDatta

Depending on where the crack is (joints), it might not hold up.

touareg

Yep, was the case, a crack in the joint, at the top, were the main pipe connects to the cat. I assume there must have been some original torsional force from the muffler.

Was just curious if this was a common failure.

For now will just spot weld and see how it works out.