Trying to find what is making a scraping/rattling sound.

[jayeh]

Hi Guys,

Lately my car has been making a rattling sound, it's especially evident when in a parking garage or going through a drive through where the sound bounces back. It sounds like a light piece of metal, like a heat shield rattling.

Occasionally I hear a sound which sounds like the when the muffler would fall off and drag behind the car. I only hear either sound once in a while. I've put the car up on ramps a few times but can't find anything loose.

Any ideas on where to look further?

[andulong]

Rear brakes might be making noise? Just a thought. Try giving a slight pull on the parking brake lever next time ( with release button pushed) and see if that makes it sound any different?

[Kaotic Lazagna]

Does it rattle at a certain rpm? Does it rattle only under engine load, or will it rattle free revving as well? I think one of my heat shields is loose as well as I'll hear a rattle around 4k rpm. This started happening after I hit a cinder block on the freeway.

[jayeh]

Rear brakes might be making noise? Just a thought. Try giving a slight pull on the parking brake lever next time ( with release button pushed) and see if that makes it sound any different?

I'll try that in the parking garage tomorrow morning. The sound doesn't seem to be from the rear brakes, sounds more like the front or middle of the car. I've had drum brakes go south on me before, and I'm used to the strange noises the rear brakes make when they get dirty and it doesn't seem like that could be the issue - but anything is possible.

Does it rattle at a certain rpm? Does it rattle only under engine load, or will it rattle free revving as well? I think one of my heat shields is loose as well as I'll hear a rattle around 4k rpm. This started happening after I hit a cinder block on the freeway.

I only ever hear it when I'm practically idling (parking garages and drive throughs). Anything is possible as I've driven though huge mounds of snow lately - but nothing appears loose. It only happens when the car is moving though, while stationary I don't hear it.

My exhaust does rattle when I first start the car though. I also found that the mid pipe was unhooked from the mounts and that putting it back in the rubber hangers made the exhaust rattle louder - but that isn't the sound I'm talking about although the two could be connected. The only place I haven't looked is behind the engine to see if I have a bad heat shield up in there somewhere.

Thanks guys!

[jayeh]

The noise still happens with the parking brake on, with the service brakes applied and in neutral as long as the car is moving. I revved it in neutral and it didn't make a difference. It's pretty strange.