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Help diagnosing and eliminating a rattling noise

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Old 12-06-2005, 08:06 PM
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Paul Marangoni
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Question Help diagnosing and eliminating a rattling noise

It's definitely coming from the driver side of the rear bumper cover. I'm pretty sure it's that thin aluminum (or whatever metal it is) that is in between the muffler and the bumper cover (almost like a heat shield). It rattles when the car is revving under 1000 rpm. Is there anything I can do to fasten that metal better? What holds it in there? I haven't removed the bumper cover to look at it yet. Does anyone have any diagrams showing the related parts?

Thanks!
Old 12-06-2005, 11:26 PM
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996NICK
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I have this exact same problem on my 1999 C2 since the temperature dropped to 6 degrees here in Southeastern Wisconsin. I think I am going to remove the exhaust system and bumper cover to find out what is loose. The heat shields aren't exactly easy to access with both in place.

The car was fine in the warmer months and has a brand new exhaust system.

I would also be interested in any bumper removal procedures or fixes to the problem.

Thanks,

Nick
Old 12-07-2005, 12:53 AM
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PTEC
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Tailpipes are pretty notorious for rattling, especially at idle. Before you get too crazy grab a hold of a tail pipe and see if the rattle stops.
Old 12-07-2005, 12:27 PM
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Paul Marangoni
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This noise is definitely the heat shield. When the car isn't even running, if you tap the bumper cover, you can hear the rattle (on the one side only). I'm just curious to know how it is attached or secured.
Old 03-20-2010, 04:03 AM
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roadsession
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Originally Posted by Paul Marangoni
This noise is definitely the heat shield. When the car isn't even running, if you tap the bumper cover, you can hear the rattle (on the one side only). I'm just curious to know how it is attached or secured.
reviving a thread back from the cold...anyone have an answer to Paul's question
Old 03-20-2010, 05:28 AM
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Pac996
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Pg 63-7 onward in the service manual.
Old 03-20-2010, 01:31 PM
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Malakas
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also make sure its not an exhaust hanger. I had a similar rattle recently, so I crawled underneath and put a rubber mallet to things to see what made noise (gently of course). It helped locate the issue...
Old 03-20-2010, 02:13 PM
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take it to a custom exhaust shop. You know the one, The one all the USA muscle car guys use. They will fix it and do a very nice job. AND do it cheap.

Other than that. Turn up the radio?
Old 03-20-2010, 09:11 PM
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roadsession
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Ok I went under the car this afternoon determined to find the noise.
I would say it is not really a rattle - it is more an intermittent chatterinng noise. Like a very fast metallic prrrrrt sound at the moment when I depress the throttle and disappears right after that.

Very annoying.

It turned out to be the exhaust tip on the driver's side. I hit the tip and it duplicated the sound.

But the bolt holding onto it was rusted and barely turned so I WD40'd the bolt and nut, removed it, treated it, and put it all back together.

Noise is gone.
Old 03-20-2010, 09:47 PM
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Macster
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Originally Posted by roadsession
Ok I went under the car this afternoon determined to find the noise.
I would say it is not really a rattle - it is more an intermittent chatterinng noise. Like a very fast metallic prrrrrt sound at the moment when I depress the throttle and disappears right after that.

Very annoying.

It turned out to be the exhaust tip on the driver's side. I hit the tip and it duplicated the sound.

But the bolt holding onto it was rusted and barely turned so I WD40'd the bolt and nut, removed it, treated it, and put it all back together.

Noise is gone.
Good job as far as you went with it.

Hate to rain on your parade but you should have replaced the fastener with new. And any other related hardware fasteners as well. If one is loose worn rusted enough to rattle chances are more are or soon will be.

Sincerely,

Macster.
Old 03-20-2010, 09:55 PM
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roadsession
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Originally Posted by Macster
Good job as far as you went with it.

Hate to rain on your parade but you should have replaced the fastener with new. And any other related hardware fasteners as well. If one is loose worn rusted enough to rattle chances are more are or soon will be.

Sincerely,

Macster.
agreed - but I plan on installing the fabspeed dual tips :-)
I looked under the car and I couldn't see how I could possibly reach the clamp that holds the current pipe/tip assembly in place. Any ideas?
Old 03-20-2010, 10:53 PM
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gota911
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You have to remove the mufflers.

You probably want to know how to do this so ...........................


Muffler removal/install
Old 03-20-2010, 11:41 PM
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redridge
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There will be more noises.... these cars are getting old. But still pretty to look at.



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