Loud whirring noise - rear wheel bearings?

[vmaxjude]

My 54K miles 1996 E220 coupe has developed a whirring noise that is speed sensitive - the faster the car goes the louder it gets. When I put the car into neutral while driving the noise does not stop, so I'm assuming it is not transmission related. Possibly rear wheel bearings? It does not alter in tone or volume while steering.

I have made a short video (1m 37s) that records the noise - it is clearest in the last 30s or so:

https://onedrive.live.com/redir?res...791&authkey=!AJkm63sRNgt8Wn4&ithint=video,mp4

Can anyone confirm what it might be? Many thanks. Jude

 

[BlackC55]

Jack the car up and spin the wheels and you should be able to locate it

 

[Teshie]

Cheap rear tyres?

 

[vmaxjude]

They would have to be from a cheap Chinese tractor to make that noise. They are decent matched Goodyears all round.

 

[ChrisEdu]

If it sounds like a wailing ghost, it might well be bearings. I had this on the front of my S211 and although three different mechanics checked it and all said the bearings were fine, once replaced, the noise stopped!

 

[grober]

When I put the car into neutral while driving the noise does not stop, so I'm assuming it is not transmission related. Possibly rear wheel bearings? It does not alter in tone or volume while steering.
Can anyone confirm what it might be? Many thanks. Jude

Since everything aft of the gearbox will continue to rotate due to being fixed to the rear wheels you can't rule out the propshaft- in particular the centre bearing and UJ's. As BlackC55 recommends jack it up and rotate by hand for starters.

 

[andy27168]

Hi,
Does the wining change tone or even disappear when going round a bend if it does it will be one or other of the rear wheel bearings.

 

[vmaxjude]

The whine does not change tone when going round a bend. My mechanic (who is Merc trained) is pretty sure it's the diff. It's going in to him tomorrow so I will know soon enough. He has some gadget(s) that he attaches to the prop and diff that can tell him if they are the culprit. I've found a cheap used diff off a well maintained car so I hope it's the diff!

 

[stwat]

It sounds like the central prop bearing to me.

 

[ChrisEdu]

Any updates on what your mechanic found or suggested?

 

[vmaxjude]

Yes Chris. My mechanic told me yesterday that after testing the car he found out that it is definitely the differential. This is good news as I found a diff off a 111K mile car with full history for £125. Hopefully my car will be back on the road by the end of the week. The car I am getting the diff from is being broken and I have bought another part off it that I needed, plus I may buy some more bits. So a happy ending financially. Thanks for your interest.

 

[ChrisEdu]

Good luck, I hope it cures the problem for you. Let us know if it works.

 

[grober]

Yes Chris. My mechanic told me yesterday that after testing the car he found out that it is definitely the differential. This is good news as I found a diff off a 111K mile car with full history for £125. Hopefully my car will be back on the road by the end of the week. The car I am getting the diff from is being broken and I have bought another part off it that I needed, plus I may buy some more bits. So a happy ending financially. Thanks for your interest.

Is it from the exact same model/time frame ? There's something in my mind about changes to the differential output flanges to the drive shafts at some point and obviously minor changes to diff ratios with the different models i.e. not all W124 diffs are the same.

 

[vmaxjude]

Update on my car - the diff has been fitted and the old girl purrs like a kitten on goldtop again. Result. The whole repair was about £300 all in. The diff was from a 1995 M111 engined car, and mine is a Jan 1996 M111 car so no problems with compatibility. I paid £200 plus postage for the diff and a dashboard top (mine had some horrible mounting gubbins for an obsolete piece of tech glued to it - when I removed it the glue was still there and cannot be removed). Parts from 'Mercedes Mark', a very nice Merc breaker in Ledsham, Cheshire (Mercedes Mark).