[Z06] Odd knocking noise down below....
Thread Starter
Racer
Joined: Jan 2009
Posts: 279
Likes: 1
From: North Port Florida
Odd knocking noise down below....
Alright get your minds outta the gutter 
I'm hearing at idle whether in gear or out of gear, what sounds like a dull metallic clanking/knocking/rattling sound. It seems to originate from under the car and I can't localize it to the front, rear, or somewhere in the middle. First guess without being able to see it is possibly the exhaust pipe tapping against something?
No ramps or lift access so I can't crawl underneath to see for myself. Wondered if anyone in Z06-land has any ideas. The car is all stock and has 17k miles (2003Z), I posted in general section too, but got no love, there... This sound is driving me nuts since it can be heard inside and out......
I'm hearing at idle whether in gear or out of gear, what sounds like a dull metallic clanking/knocking/rattling sound. It seems to originate from under the car and I can't localize it to the front, rear, or somewhere in the middle. First guess without being able to see it is possibly the exhaust pipe tapping against something?
No ramps or lift access so I can't crawl underneath to see for myself. Wondered if anyone in Z06-land has any ideas. The car is all stock and has 17k miles (2003Z), I posted in general section too, but got no love, there... This sound is driving me nuts since it can be heard inside and out......
Thread Starter
Racer
Joined: Jan 2009
Posts: 279
Likes: 1
From: North Port Florida
nope. it's still there with the clutch pushed in or with the car out of gear and the clutch is out. If it helps, the odd sound is not consistent with acceleration/RPM changes either. Just harder to hear when revved due to engine sound. it "kinda" resembles the sound you hear when a car diesel's but its not quite the same. Doesn't seem to be coming from the motor, but somewhere behind the motor and underneath the car.
Last edited by KWIKSILVERZ; Feb 20, 2009 at 03:31 PM.
Burning Brakes
Joined: Jun 2004
Posts: 1,184
Likes: 3
From: KADS- If it has wings or an engine, I can break it. Dallas TX
Probably just gear rattle. Mine does this also.
Put the car in neutral, take your foot off the clutch and then turn the key off. Is that the sound your hearing? if so, its gear rattle. and its normal on a Z06.
Put the car in neutral, take your foot off the clutch and then turn the key off. Is that the sound your hearing? if so, its gear rattle. and its normal on a Z06.
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Thread Starter
Racer
Joined: Jan 2009
Posts: 279
Likes: 1
From: North Port Florida
get it fixed on them.
Burning Brakes
Joined: Nov 2008
Posts: 764
Likes: 0
From: Arden NC
Nope that's a different sound altogether. I am almost certain it's a failing cat. I crawled under the car...well kinda just did some reachin' and tappin' around and it's almost definitely in the pipes. I used a piece of garden hose to listen for sounds...and it actually workd well enough to get me in the area of the cats and away from the tranny. If GM's emission warranty is good for 7 years, I think it's a possibilty I can
get it fixed on them.
get it fixed on them.
Melting Slicks
Joined: Apr 2007
Posts: 2,107
Likes: 4
From: Northern VA
Thread Starter
Racer
Joined: Jan 2009
Posts: 279
Likes: 1
From: North Port Florida
Thread Starter
Racer
Joined: Jan 2009
Posts: 279
Likes: 1
From: North Port Florida
noise confirmed...
To close on this, I took the Z to the dealership to confirm my belief that the Cat(s) were failing. As I pulled in to the service entrance my check engine light came on and the DIC threw code P0430 which would later translate to the #2 Bank (right side) catalytic converter not operating efficiently. The cat is covered by the GM Emission warranty for 8 years/80,000 miles for those who wanted to know and will be covered! 
Anyway, prior to taking the car in I noted that there was an ash-gray colored soot built up in the exhaust tips on the right side. Just another indicator. Thanks all to who offered suggestions. It was/is very much appreciated! 
Anyway, prior to taking the car in I noted that there was an ash-gray colored soot built up in the exhaust tips on the right side. Just another indicator. Thanks all to who offered suggestions. It was/is very much appreciated!
