Wheel bearing type noise above 40 (W204 C280)

[nbevans]

Just got back from an indy garage whose been trying to diagnose this. He's ruled out the wheel bearings, and various bearings on the propshaft. All those seem to be fine. He is now thinking it might be a bearing or cog in the diff, or the gearbox (7g auto) itself. We had previously changed the diff oil - but this made zero difference to the noise.

PS: The noise is road speed related - since putting it in Neutral makes no difference to the noise.

What does PH think?

Edited by nbevans on Thursday 29th August 17:35

[Monkeylegend]

Have you checked for tyre noise ?

I had very similar which sounded like wheel bearings, and when you ran your hand backwards over the outer edge of the front tyres you could feel feathering.

Mine were non directional so I switched them side to side on the front so they were running in the reverse direction and the noise disappeared.

If they are directional you could try switching front to back and see if the noise moves with the tyres.

[tobinen]

Worn V-grooved tyres can do exactly as you describe. I had this on my 210 and it was doing my head in. Bearings all OK. Swapped the front tyres to rear and it was greatly improved. I'll never have V-grooved tyres again

[nbevans]

That's a good shout and am investigating further on that now. Seems to be called "saw toothing" on Google. Thanks

[nbevans]

They are ContiSportContact's on the rear and some "Jinyu" on the front. Sizes seem different though. Saying that, didn't see any directional arrows on them. So could still try swapping them left/right on each axle...

[Monkeylegend]

I would do that for a start, costs you nothing.

Having said that I have never heard of JInyu, sound like a cheap pair of ditch finders.

You could put the contis on the front to see if that makes any difference, if it does it could be time for two new decent
tyres