How to locate a metalic rattle under the car?

[jtzako]

I have a metalic rattling noise coming from someplace in my car. It sounds almost like a washer rattling against something else metal. I cant hear it all the time but it sounds like it may be under the car someplace. I can only hear it when I drive past something that reflects the sound back towards the car it seems.

I've put the car up on ramps and cant find anything loose. I even shake or bang on the exhaust in various areas and hear nothing. I also cant find anything that seems to be loose.

So far the only thing I can find that makes any noise at all is the lower section of the rear bumper but that sounds more like a squeak than a metalic rattle.

Anyone have tips for finding this noise?

[GTAHVIT]

If you have 3" exhaust. I'd bet $20 that it's the exhaust hitting the tunnel brace.

My guess is it's an exhaust rattle of some kind. I've still got one I'm chasing down. some where near the diff.

Edit:

Mine doesn't do it all the time either. But there are some things to help you find it. get the car up off the ground and look for any spots on the exhuast that show signs of beeing rubbed or scratched. it might look shinnier than the rest of the pipe... that and check the tunnel brack for spots where the coating has worn off...

That will help you try to find it visually... don't expect the wear spots to be very big, could esily be smaller than the size of a dime... more like half that size.

good luck!

[jtzako]

I have stock exhaust except for solo Hi Flow Cats. I dont currently have the cross brace on the car so it isnt that for sure. Also, it doesnt sound like impacts, it sounds like rattles. It happens when just driving on a relatively smooth road surface even (though it is louder when on a rougher road).

[Hawkeye David]

I have the same sound and the car is all stock. It's gradually gotten louder and you hear it now from 35 to 50 with very little engine pull. If I press the clutch or accelerate a bit it will stop vibrating until there is less torque.

[GTAHVIT]

My guess is you may have a baffle that's come lose in either the muffler or the resonator..

A couple cars have had this problem... you should be able to get it fixed at the dealer.

[jtzako]

I'm starting to think it might be the rear bumper or at least the diffuser part. I have looked all over, including banging on the exhaust cans and cannot cause anything to make a similar noise. However, if I grab the bottom of the diffuser and move it up and down quickly it squeaks quite a bit. It could very well be that noise I am hearing.

Now to figure out if I can do something about it.

[GTAHVIT]

You might try a little Wd40 or some silicone spray to see if that gets rid of it.. then you can try something more permanent

[jtzako]

I tried WD40 along the seam between the bumper and diffuser but that did nothing. I'll probably have to take the thing off and work from the inside.