Exhaust Rattle

Aaron

Dirt-Old 20+Year Member
Dec 5, 2003
93
35
38
Buffalo, NY
Hoping someone can confirm my suspisions...

Towards the middle of last summer, my '87 GT developed a very annoying rattle that sounded like it was coming from the exhaust. It's very loud when the car is cold and quiets down a bit when the car is warmed up but it never completely goes away. At first, I thought there was something loose, but that idea went out the window because I replaced the clutch towards the end of the summer and the sound never changed after the exhaust was put back together. I am thinking the sound is coming from my BBK (junk) H-Pipe with cats. Could something be rattling inside one of the converters?

Here's a link to the sound. Rattling Sound

Let me know what you think it could be. I'm ready to buy an X-Pipe with cats (probably from Bassani this time), but I'd rather not spend the $$ if it is not the problem.
 
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I dunno man, usually exhaust rattles are a little higher pitched than that. Doesn't mean it isn't from the exhaust though.

Do you have a stethpscope? Maybe you can put it on the cats and see if you can pinpoint it?

The vid is hard to tell since you can't listen and try to pinpoint where the noise is coming from, but based on the sound alone, i'm not convinced 100% it is exhaust. Doesn't mean it isn't, but i can't tell from my seat here
 
I would say something, but it has basically already been said.

1.Hard to tell from video

2.Might not be exhaust

You might want to take it outside the garage and out into the open and make a video. There might not be so much echo, and it would be easier for us all to hear it.:shrug:

In my opinion, I would say its coming from the cats, but it might not be, just like everyone else has said.

If you eventually get tired of it and can't figure out the problem, then here's what I would do. Get someone to cut the cats off for you, and sell them. Then get someone to weld in straight pipe so then you can sell it as an offroad h-pipe. I guarantee SOMEONE will buy it. I don't know where you live, but around here a single cat will go for $84 bucks a piece. The scrap guys pay big money for them.

All that money can be put towards a new pipe or something else.

See if you can get another video in here.
 
I agree that exhaust rattles are usually higher pitched, but it's hard to tell what it sounds like from the video. My buddy had an idle rattle under his car forever, even after it had been taken apart and put back together a few times for various things. He finally decided to actually find the problem this weekend, and it ended up being one of his o2 sensors falling apart. Just another place to look.
 
I had a similar problem a little while back. It turns out it was the heat shield thingie on one of the cats that came loose. All I had to do was literally reach under the car and I could pull it out from over the cat. The sound wasnt exactly like the one in the clip. It was slightly faster and higher pitched.
 
I recently removed my cats after one developed a rattle. I initially thought it was the heat shield but it turned out to be internal. It actually behaved just the opposite of Aaron's. It would be relatively quiet when the car was cold but the warmer the car got, the louder the rattling. The sound from the video clip is very similar though. FYI, this was a Catco h-pipe I had on my '92.
 
I was gonna say but someone beat me to it sound to me to be your heat shield on the cats. I would check both sides see if its rattling on top and yank the thing off. I have had this happen a ton of times to me and welding the cats back up are just a waste of time its just a basic spot weld and they come loose again soon after. Mine would always rattle the worst when I would sit idling at like a drive thru with building be soo close it would make it sound twice as bad.
 
rattle

mine does that too!!!i have off road pipes on mine and really isnt that noticable unless i get on it .......I really notice it when i am on the highway and in the third lane close to the barrier ...thats when it echos the most and you can try to pin point the problem area....
 
OK - I am now more confident that the rattle is coming from one of the cats.
Here's a new video: Rattle Part 2
As the camera gets close to the converters, it gets much louder. If I stay near the pipes going closer to the headers, it's not as loud.
Judge it for yourself and let me know what you think...
Thanks.
 
Well sitting at my desk at my laptop, i would say it seems like it is the cat.

Take the h-pipe off and start the car and see if it goes away :)

hell with the h-pipe off you could prob shake it and hear it rattle
 
Well sitting at my desk at my laptop, i would say it seems like it is the cat.

Take the h-pipe off and start the car and see if it goes away :)

hell with the h-pipe off you could prob shake it and hear it rattle

Thanks for your comments. I think we're both right...I'm trusting my gut instinct and just bought a Bassani X-Pipe with cats. We'll find out for sure this weekend :)