Exhaust rattle
Thread Starter
Burning Brakes
Joined: May 2006
Posts: 904
Likes: 0
From: Boynton Beach FL
Exhaust rattle
Hi all,
Been trying to track down this noise coming from underneath.
Makes this horrible rattling noise, if it is hot or cold, between 900 and 1800 rpms, in gear or not, with clutch depressed or not. Only seems to go away when above 2000 rpms (and I'm running with no mufflers, so I'm guessing I just can't hear it anymore!
)
So it sounds like its coming from the cats, or possibly the resonator or the heat shield.
Nothing is visually vibrating or making lots of noise, sounds as if it's internal to something.
I tried hitting the cats with a rubber mallet, and I don't hear any jingling/rattling from inside.
On one of the pipes coming from the cat to the resonator, the pipe has been crushed/dented a bit on the bottom, looks like previous owner may have tried to jack up the car on the exhaust? I've had the car 2 years without a problem though...
This sound is very embarassing, killing me to drive around like this. Thoughts on what to attempt next?
(Remove the cats completely, and just run straight pipe? Buy headers?
Been trying to track down this noise coming from underneath.
Makes this horrible rattling noise, if it is hot or cold, between 900 and 1800 rpms, in gear or not, with clutch depressed or not. Only seems to go away when above 2000 rpms (and I'm running with no mufflers, so I'm guessing I just can't hear it anymore!
)So it sounds like its coming from the cats, or possibly the resonator or the heat shield.
Nothing is visually vibrating or making lots of noise, sounds as if it's internal to something.
I tried hitting the cats with a rubber mallet, and I don't hear any jingling/rattling from inside.
On one of the pipes coming from the cat to the resonator, the pipe has been crushed/dented a bit on the bottom, looks like previous owner may have tried to jack up the car on the exhaust? I've had the car 2 years without a problem though...
This sound is very embarassing, killing me to drive around like this. Thoughts on what to attempt next?
(Remove the cats completely, and just run straight pipe? Buy headers?
Pro
Joined: Nov 2005
Posts: 602
Likes: 0
From: North Bay Ontario
I'd be suspecting one of your cats. Figuring out which one might be a challenge. My '85 has only the one cat and had the rattle. After eliminating the possibility of a loose clamp on the exhaust pipe ahead of the cat which holds the egr tube, I narrowed it down to the cat. Something to think about, once the guts of the cat break into pieces, it is possible for a piece to move on down your exhaust system and be lodged and/or rattling there. Oh yeah...what clinched it for me was the day that I saw and removed a few pieces of the broken guts from the exhaust tips on one side.
Melting Slicks
Joined: Oct 2006
Posts: 2,314
Likes: 3
From: In a van down by the river! Florida
had a similar problem, same RPM too, one of the tack welds on the heat shield broke and cause an awful buzzing rattle between the same RPM.
Just had it re-tacked in and all has been great
Just had it re-tacked in and all has been great
Thread Starter
Burning Brakes
Joined: May 2006
Posts: 904
Likes: 0
From: Boynton Beach FL
Oh, it makes the noise at idle, I can still hear it when I'm under the car. It's just such a racket I can't tell exactly where it's coming from.
I think I'll try an exhaust shop today, see if they can figure it out...
I think I'll try an exhaust shop today, see if they can figure it out...
Safety Car
Joined: Jun 2006
Posts: 3,629
Likes: 28
From: FL
Spotted these in the Parts for Sale forum, should be the same as a 93 if you are interested.
http://forums.corvetteforum.com/show....php?t=2103014
http://forums.corvetteforum.com/show....php?t=2103014
Le Mans Master
Joined: Sep 2006
Posts: 6,050
Likes: 147
From: Phoenix AZ
2021 C4 of the Year - Modified Finalist
noise
are you sure it's the exhaust and not the fuel lines? Chevrolet put out a bulletin in 1986 about fuel line rattle . They put a fuel filter in the return line back near the tank to dampen out this rattle.
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Burning Brakes
Joined: Feb 2008
Posts: 988
Likes: 7
From: Sarasota Fl
Concerning the 'dent' in the pipe, I believe somebody posted something about this recently, saying he believed his auto shop did it. Members with the same model year replied that it is a stock 'dent' in the pipe. IIRC, the dent you speak of was located on the passenger side behind the cat, near the front of the rocker panel. This would look like someone had jacked it incorrectly. I think I heard it may have served a purpose in reducing sound, don't quote me on that, but there was a post on this recently.
Jonathan
Jonathan
