Would a dead cat rattle?

[Mike 92 XLT]

A dead catalytic convertor, that is...

Two days before I left MI, a metallic-sounding rattle started coming from the catalytic convertor area. Thinking it was the heat shield, I crawled under there and took a look. Sure enough, some of the welds on the heat shield had come loose, so I just ripped the whole thing off. But the rattle is still there. Is it possible that the "guts" of the cat have broken apart and are rattling around? How much will a new one cost me? And no, I can't straight pipe it because I'm in CA and wouldn't pass the smog check. And I don't want to spend the money on a high-flo because I'm going to be selling it soon. Any ideas?

Mike

 

[mrboyle]

My first responce was going to be, no they just get stiff, bloat and start to smell but then I read the entire post. To answer your question, yes when a cat (converter) fails it can come apart and rattle. As far as replacement goes, your going to be looking at minimum $200 for a replacement cat and labor. But there is a strong possibility that when the cat failed (depending on which one it was) material from the cat was able to work its way down the exhaust pipe and get stuffed into the muffler. If this is the case it will be necessary to replace the muffler as well.

 

[Rick]

There's another heat sheild on the Y-pipe coming from the exhaust manifolds. Mine broke a weld and rattled. Check it out.

 

[Ross-N-Chicago]

Good timing. I had recently pulled both heat shields off from rattling then just replaced with a hi flow from summit. I still had the rattling in the cat even with the heat shields off so I am assuming that something came loose or it failed altogether.

PS How do you know if you cat has failed, symptoms??

 

[mrboyle]

Originally posted by rossneag

PS How do you know if you cat has failed, symptoms??

Symptoms.... rattle, extreme loss of power, major exhaust leak prior to cat, smells like sulfer (most common on vehicles that never get driven for extended periods of time), failed emissions and (on OBD II vehicles with 3 O2 sensors) check engine light w/ code referring to cataletic converter failure.

 

[Mike 92 XLT]

Hmmm, Rick, that sounds encouraging. The sound is exactly the same sound it made when one of the welds broke on the cat heat shield last summer (I wrapped some wire around it and it fixed it). I figured that the wire had come loose over the course of the year and had started to rattle again, so I just ripped it all off. Imagine my suprise when it was still rattling! Anyway, I don't have any of the other symptoms described in the post above. Power, gas mileage, etc. is all on par, no exhaust leak, and no sulfur smell. I'll check out the Y-pipe and let you all know.

Oh, and if I need a new cat, will a 94 work on a 92? The 94s had EGR and the 92s didn't, but will that matter?

Mike

 

[Mike 92 XLT]

One more question. Do the 92s have two cats or just one? mrboyle made a reference to two in his first post, but when I crawled under there, I just found the one downstream of the Y-pipe. Are there two in one housing?

Mike