300 SD Clicking noise right front side
 

I have a 1985 300SD turbo diesel with 309k miles. I have just notice a clicking noise that is coming from the right front area. The clicking frequency increases with wheel speed, not related to engine RPM. It's like there's something sticking into the slots in the rim that makes a 30 clicks for every wheel rotation (I already checked, there isn't anything). Once above 40 - 50 mph the clicking is so fast that it isn't discernable anymore.

I first thought wheel bearings, but putting the bearing under lateral loads doesn't change the noise at all. I don't see anything that would be rubbing against the tire or rim under windload, plus since the clicking starts from a stop there's no windload to deflect anything yet. The noise seems to be forward and right of the transmission so I don't think it's driveshaft related. It could actually be comming from under the passenger dash-board/firewall area, but I don't know of anything inside the car that would be wheel speed related.

Any ideas?

Thanks.

temp sensitive
 

Some new info; it appears this clicking goes away at higher ambient temperatues, makes noise at 70F, not at 90F.

Have you jacked up the car and spun that wheel by hand?

Mike