My BMW 325is makes a rattling noise from the drivers rear. What is it?

Question

Ive taken the wheel off, everything seems solid. It's not the exaust either. It does seem to go away when I apply the brakes.

Answer 1

SHOCK MOUNTS

Shock mounts on BMWs fail pretty easily. I recommend you use Meyle's heavy duty shock mount as opposed to the stock ones.

The original part looks like this:
http://www.bavauto.com/lview.asp?imgfile=assets/imglib500/33521137972.jpg

The heavy duty part looks like this compared:
http://www.bavauto.com/lview.asp?imgfile=assets/imglib500/heavy-duty-shock-mount.jpg


From bavauto.com:
Meyle’s heavy-duty rear shock mount has an internal flange that disperses pressure more evenly, eliminating a common failure area of the stock mount.

The sound it makes is more like 2 pieces of loose metal washers rattling. And this happens only when you go over bumps. It has no negative effects, just annoying.

Changing it out is quite straight forward. But you need 2 jacks. One to hold the car up, one to gently lower the rear axle to allow the removal of the shock mounts.

Answer 2

this rattle could be from the rear gear boz mounting,the rear drive shaft oil seal loose,or the disc pads worn and having too much clearance.
check the silencer(in most cases is from inside the silencer)
please check the shock absorber too.

Answer 3

My old Bmw had this problem, it was actually some screws that got loose in the gas pedal-engine connection thing. it is not dangerous but i suggest you have a pro check it out.


hope this helps

Answer 4

I had this problem too. In my car, it was a loose heat shield.