tibbyrd2000

Before I describe my problem I have search all the forums high and low for some answers and have not found a match. To describe whats going on I just started having a crazy loud rattle from which i firmly believe is from under the car some where from after the axle back section to my headers. I know for sure it is not the axle back (rear section), or my muffler. The rattle usually occurs after the car is driven for a bit and warmed up. Mainly the rattle is present during when the car is decelerating around 4 or 3k and sometime below that. The rattle is also present when I rev in neutral and when I accelerate. To describe the sound of the noise, I would have to say it almost sounds like a heat shield rattle. It sounds like very thin metal vibrating. It is also very noticeable outside the car. FYI I also have had the car up on a lift and check for where the exhaust pipes could be hitting, nothing I could see or hear. I am running catless also so I know that is not the problem as well. Please help and put in your two cents. Thank you.

majik

it's probably a clamp around the exhaust that holds it to the chassis. When we were messing with the headers on my car, we somehow lost a bolt that holds it clamped so now it just sits there and rattle sometimes - mostly when idling. Just get on your belly and look under the car, see if you can notice a clamp just hanging there, unbolted, or maybe the bolt is loose

tibbyrd2000

Thanks for posting, clamps are fine and all bolts are tight. Any one else have suggestions.

Bommello

I had this happen to me... seems to have been the muffler. I upgraded my exhaust and now it's gone.

Stocker

Could be a broken part in the muffler, could be a bit of broken catalyst honeycomb in the catalytic converter. Bang on the cat and see if it bangs back. Similarly, tap the length of the exhaust with a hammer. Heck it really could be the heat shield loose, tap that also.

tibbyrd2000

Thanks for the posts. I have ran the car with out the muffler the rattle was still present. There is no heat shield on the car, not even the one under the car.

Stocker

Who took it off? It came with one or my car is WAY different than yours.

tibbyrd2000

I did lol, to see if that was the problem. I was to lazy to put it back on. Any one else have suggestions???

Stocker

My wife's truck has a rattling bearing on the end of the front anti-sway bar. Really your noise could be nearly anything. Get down there and yank and knock on *everything* under the car, check all the bolts. OOOOh be sure to check the front brake components (thin metal plate might be loose? ) and all the little brackets. Check the suspension mounting bolts and lugnuts also. Maybe if you can't find it, pull off the inner fenderwells and see if something is kicking around in there.

You already gave a pretty detailed list, but see if you can find a set of circumstances that always, exactly that makes the noise. Then a) tell us and b) have a friend ride along and see if they can hear it. If it can be arranged, and the speeds are low, and they are young/stupid, have them put a helmet on and ride on the hood or fenders, or maybe with the hood up (if you can get the noise in a parking lot or something traffic free)

I am guessing you can't get the noise to come around when the car is still, or wheels-up on a lift?

tibbyrd2000

Thanks stocker I will try all of those things and see if I can produce the sound while it is on jack stands. Ill let you know.

I got under the car today and reved the car up. I am pretty sure it is coming from the resonator, or test pipe. Can resonators go bad, mine is the one that come stock with the obx exhaust. Let me kno.