Loud noise coming from underneath car on a 97 E320 (W210)?
 

Hi,

I have a 1997 E320 with approx. 83k miles on it, For the last 10k miles the car has been making this loud kind of ratling noise, kind of like pipes rattling around, It used to only happen with the a/c on, but now it comes on all the time even without the a/c on, This happens when the car is warm, I have taken it to the dealer on several occasions and they can't seem to identify the problem (Lazy bastards), so this is my last resort, the car was just in for a tune up this past weekend, and the noise still continues, any ideas???

Thanks

Had that on the 190E we aquired, and found a loose heat shield intended to be tack-welded over the exhaust pipe, just south of the manifold downtube. I think the pipe may be a 'pre-cat'.

On other cars, have found similar things, but sometimes it is from an internal exhaust baffle. The only solution there is to replace the offending component.

As far as diagnosis, if internal, it may be very difficult to find if the car needs to be under load, because someone needs to check underneath for it. Can you get it to happen in 'park' with lights, a/c on, foot on the brake, etc?

Steve

The noise comes, regardless what gear it is in, as long as the car is warm and the engine is running, the noise exists

How can i tell if it is the heat shield? do i have to go under the car?

Thanks

Well, if it will occur with the engine idling up on a lift, the shop should have no trouble locating it.

In the case of our 190, it was easy - the shield was completely loose, external, and was found with a cold inspection (engine off).

Steve