I have a Hooker catback on my car and I have a really loud rattle, but it only happens when the car is warm. I've looked under the car and don't see any rubbing, but it sounds like it's coming from the muffler. My guess would be maybe something inside the muffler is loose and when the muffler warms up it starts to rattle.

Any ideas? I'd replace it if I have to, but I want to be sure. Thanks.

Brian

 

I was having a similar problem. Only presenting itself when warm. Your best bet would be to warm up the car, and leave it running and crawl around under it to find the problem. As the exhaust pipes warm up, they can expand a little, and possible bump/rattle against something when they wouldn't if cold.

 

I'll leave it running and throw it up on jackstands again when I get home. I've tried that already but I might have missed something.

I forgot to mention it only happens at certain RPM's so that makes it even harder to troubleshoot.

 

Hmmmm, so it's a resonation rattle then?? Do a real good once over where everything is, paying special attention to "close to other object" areas. Look to see if there's any scuffs or anything. How old is the exhaust system, and is it stainless or not? If it's stainless the muffler shouldn't be coming apart on the inside.

 

Yes, it's resonation. The exhaust is only about 6 months old and it probably only has 2,000 miles on it. I didn't see any rubbing but I'll check it out thoroughly when I get home and post on here if I find anything. Thanks for the advice.