[ktd]

Hi guys. When I leave my 05 CC coupe at idle for more than 10 minutes parked, I begin to hear a loud rattling coming from the rear of the car. Its consistent every time. Sitting for a few minutes, its quiet. Then after a period of time it start making loud noises, especially if its in the garage like something loose and clanking. Its not coming from the exhaust pipes. The dealership told me that is normal for these types of cars. Does everyone's coupe do this or just something my dealership didn't want to look into?

 

[Doron]

As far as I know it comes from the muffler itself, you might have some loose pieces of metal in the muffler. I hear it from my right muffler when the car is running in idle .

 

[Ramp]

especially if its in the garage like something loose and clanking.

The garage is amplifying the sound and can be your friend in finding the problem. It's not normal and the obvious is something is loose - probably tightens up a bit when cool and loosens when hot - although this is generally counter intuitive. Could be some loose metal in the mufflers OR your cats breaking up.

Leave it idling in the garage and try and isolate the noise. DON'T kill yourself so keep the garage door fully open !

 

[Glenn Wallace]

I've heard this from my car when I leave it idling (in neutral duh - CC) for a long period of time and I'm outside the car. I thought it might be a transmission/driveshaft issue but if you think about it with the clutch at the front of the car, nothing should be turning at the back of the car.

Then I thought it might be cats, but then they're at the front too.

It does sound like something rattling or clunking under the back of the car.

 

[BigFoot]

Rattling noise at idle is usually associated with damaged cats, isn't it?