I've been trying all day to track down this annoying rattle in my exhaust. I have the car jacked up and I've been banging away all day. And it seems like it's comming from inside one my of my passenger side cat... does this make sense? Can the internals of a cat rattle? It seems to go away when the exhaust is fully warmed up (which obviously makes sense because everything would be fully expanded and tight)

But it's still annoying when cold. My passenger side LT header does vibrate agaist the K-Member.. but thats not the source of the rattle.

Oh and if I hold the cat and hit it.. the rattle seems to be gone. Maybe it's just because I'm absorbing it, but would putting header wrap around it help? (Can you even put header wrap on cats?)

Any suggestions on fixing exhaust rattles in general too would be nice

Thanks!

 

Sounds like the honey comb in your cat has broken apart. Expecially since you can hold it and it stops the vibration. That would stop the pieces from shakeing around inside it (some). I think you should just gut them or replace with hi-flows.

 

Yes the internals of the cat can get loose and rattle, beat on it with the palm of your hand and see if it will rattle for you or they usually rattle while sitting at idle.

 

My passenger side cat rattled like a ball bearing in a 55 gallon drum when I had my subframe connectors put on.

I went to a local exhaust place - had them sawzall the old one out and weld a new one in its place - $150 for everything.

CCRJon

 

Mine started with a rattle on my Bird then it clogged it grrrrrrr

 

Ugh... this custom y-pipe has been nothing but trouble since I got it. It's crappy, ugly and a very sloppy job. And on top of that it wasn't cheap!

I was all for keeping my cats because I need to stay emissions legal. What should I do?? I was thinking about hacking off my y-pipe but keeping it. And buy a mufflex full 3" y-pipe.. then come emissions.. hook back up the crappy y-pipe. But I didn't really want to have to do that. That's why I opted to keep my cats in the first place.

What should I do??

 

Cats don't last forever. Are they original? If so they are shot. If they rattle they are shot. What should you do? Replace 'em.

 

Original? They are brand spankin' new! I bought them brand new when I had my custom y-pipe fabbed up. This is about 2.5 months ago!

This is what I think happend.. when I first had my y-pipe made.. the guy completely screwed up.. so I took it back and he had to do it over again. I wouldn't be surprized if the guy dropped the cat, banged it, hit it with a hammer to get it off etc... he was a real scum bag.

I just took the car out for a spin.. and oh boy is that noise getting worse. It sounds exactly how you describbed it CCRJon, like a ball bearing in a big metal drumb.

With cats at 200 bucks a pop up hear.. I'm NOT spending that kind of money on this. I'm thinking about getting the mufflex still.. but what should I do come emissions?

lol what a pain in the ***! Thanks guys...

 

yeh if its ratting on the inside its busted, only way to fix it is take it off and get a pipe that will fit inside of your cat and ram it all the way through until the catylist falls out in peices, instant ''high-flow cat'' if you dont have to pass a sniffer test

 

I just had a cat fail on my car earlier this week. Fortunately my car is still under warranty, but the noise didn't even sound like it was coming from there.......I seriously thought I had a broken flexplate or something!? BUT, it turned out to be just the cat.

You could do what "blwnlt4" is saying and put a pipe straight through the cat's and eliminate them. I believe that your car would still pass an e-test no problem up here (my carbureted '81 Z28 failed worse after I installed a set of cat's on it? ).