W126 Loud Squealing sound
 

Its unfortunate that this squealing problem came just about the same time as the difficult warm start problem. :(

The loud squealing sound goes "eeeEEEeeeEEEeeeEEEeee......."
alternating between a higher note squeal ("EEE") and a lower note squeal ("eee"). It comes on when the car moves on straight, and not when turning or reversing. And it only comes on after some driving, not when cold. I cant hear it on the highway, probably because the road noise is louder. But in the quiet carpark, the squeal is very much audible. No noise though when stationary with the engine running, so I've ruled out the belts.

Parking brake is off, springs and shocks are new, rims and tires are very new. I'm not looking for an exact answer to this problem as I know noises are hard to diagnose, but I would like to hear some similar experiences so that I could zero in on the source in the right direction.

Any clues anyone?

Thanks!
:)
W126 1983 (280SEL)

Hello there!

I had some squealing noise but only when it has been running hot. Yesterday as I had the discs and pad replaced, we noticed the brake pump needed repair as the seals were worn through. NOW, they suspected that could have been the source.

It may be a little different in your case but I would suggest taking out the discs and see if its aligned sturdy in place.

Otherwise, would it be coming from your front wheel assemly?

Hi Kerry, how have u been? :)

The squealing problem is very new, and I doubt it could be the discs or pads since they were problem-free ever since I changed them last year. Besides, the loud high-pitched squeal comes on when the brakes are not engaged. But I'll go have the brake assy checked anyway.

I'm guessing it might be coming from other under-carriage parts, but I really am clueless to what specifically it is. The squeal is continuos, and only comes on after some amount of driving is done, when cold, there is no squeal. And it squeals only when the car is moving in a straight line, not when turning or even reversing. I'm baffled.

Anyone can throw some light on this? Thanks!

:confused:

Maybe you ought to get the mech to check your rear axle and bearings?

Start with the basics, such as worn/loose belts, then go from there... what was done or changed due to the warm start problem?

Kerry, I'm getting my rear axle relubed tomorrow, so I'll get the mech to check on all that is there.

w126, I'm replacing all 3 belts tomorrow too, but the squeal cant be due to the belts as it only comes on when the car is moving. With the engine running in the stationary car, there is no squeal. I still have yet to pinpoint the cause of the warm start problem, but as I was advised by Stevebfl and JP, it is more likely a vacuum problem rather than a fuel problem. I'll get my vacuum lines and valves checked tomorrow, and according to Steve, there is a suspect called the decel dump valve which might be the cause.

Listened to the car again this morning after a 20 mins drive, the squeal is definitely coming from the front!

When it squeals again, does applying the brakes make the squeal go away?

I know how annoying these noises can get and would sure like to know whats the cause.

Good question, I'll try it later and I'll let you know. I agree it is very annoying, people will think the car is a piece of junk with that loud irritating squeal!

:mad: