Hi Guys,

Need your input on this issue. Lately, my 1985 W201 190E 2.0 (Manual Transmission) started to produce a high pitch humming or whining noise whenever I drove the car after leaving it overnight or more than 4-5 hours especially in the mornings.
But what baffles me though is the sound will totally disappear after I travel between 3-5 miles.
I do not think it's the wheel bearings because it only happens at low speeds between 15-25 MPH and no noise at all above that speed.

I have changed both my transmission fluid and diffrential oil using Castrol synthetic Gear Oil. But no improvement at all.

Anyone gone through this before?

if you had a worn in differential wear whine it WOULD NOT go away after a while no matter how long you drive. It will be more evident at certain speeds and you should be able to vary the sound by slightly accelerating and coasting. The only way to erase a rear diff whine is to replace the ring and pinion gears. Even new bearings and clutches will not erase a diff whine. Heavier weight synthetic fluid and a blanket or other sound proofing under the rear seat will mask it though

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Christopher Henkel
1990 190E 2.6 - Arctic white SOLD
1986 190E-16v - Blauswartze
1993 300CE - SOLD
2003 W208 CLK 320 Cabriolet - Magma Red

I just had a noise, vibration, and grinding problem from ... tires. Cheap worn out Kumho tires. A low speeds around 18-22 mph They made a grinding noise that I could feel through the steering wheel - could've sworn it was wheel bearings. At higher speeds they were noisy and still made somewhat of a grinding vibration - thought maybe it was my driveshaft bearings. For six months I toiled over it never thinking it could be from tires, but it was.

I finally took my car (CLK 430) to an independent shop 3 weeks ago where a set of wheels with new tires were swapped on to my car. I drove it ... all noise gone. Since then I replaced the Kumhos with a set of Bridgestone RE050A Pole Position tires and the ride is sweet.

Anyway, tires might be something to look into, although you mention the noise goes away after a few miles, and that's odd. Are your tires about worn out? Any strange wear patterns? Also, my Kumhos would develop flat spots from sitting overnight which would work out after about 5 miles ... maybe that's it.

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2000 CLK 430
2004 BMW R1150RT
2001 Honda VFR800i

I tried 140 weight diff oil and you are right.... even applied sound proofing mats under the entire carpets..

I am currently running on 205/40/17 Nankang NS-2 tyres bought early this year. But the whining noise were there even before I changed the tyres.
You are right about the Kumhos though....tried a set before....didnt like it...

Maybe I'll try to replace the wheels bearings next.....

But what baffles me most is why does the noise go away after I travel more than 5 miles???

My rebuilt rear diff is on the way back and I will install it soon, hope she doesnt whine. The LSD will be working again, but if its ring and pinion gears have enough of a worn spot in them like my current rear diff, I will get to continue to listen to the whine. At least the LSD will work, I'm keeping my fingers crossed. My rebuild guy seemed to think the gears looked good.
The heavier oil and sound proofing only masks the noise so much and almost not at all with the windows down.
As weird as it sounds, my old German mechanic, who seems to know everything about MB and I trust, got in the trunk of my car, closed the lid and told me to drive. i did. We went for at least 5-10 minutes with him back there in the trunk while I was driving though town. He was listening for the noise. I has a clunk and a whine. HE not only pinpointed the location and parts that were making the noise, but also knew which side. It can be very hard to do by yourself from the driver's seat. The noise can "move" depending on what it is echoing off of and what not. Maybe you can find a trusting pal to ride the trunk. It will make sure you dont replace wheel bearings on a whim. Sometimes the bearings are dry and the heat created from movement can lubricate them and they can stop some of the noice after a few miles, But if that is the case, they still need replaced, they will self destruct eventually. Good luck.

__________________
Christopher Henkel
1990 190E 2.6 - Arctic white SOLD
1986 190E-16v - Blauswartze
1993 300CE - SOLD
2003 W208 CLK 320 Cabriolet - Magma Red

That is exactly what I thought could be the cause.....The lubricating grease could have been hardened and after 5 miles on the road it could have melt again from friction.....Anyway I will find some time to get the wheel bearings replaced.....Will update you guys once I got it fixed....

Thanks for sharing.....

Never forget that when we replace wheel bearings we do it by weight. Put the recommended weight ( ounces not viscosity) in the bearing. Also, this is partly because the grease will heat and become more liquid. The correct amount of grease will insure that the bearing is always lubricated. If grease has hardened, leaked out, etc you will have less in the hub to lubricate. As is heats and moves around in the hub ( albit not a lot of moving and melting) but it can provide the needed lubrication that is missing until the existing grease warms and moves possibly into the bearing more effectively. Not a guarantee, but it is a possibility.

__________________
Christopher Henkel
1990 190E 2.6 - Arctic white SOLD
1986 190E-16v - Blauswartze
1993 300CE - SOLD
2003 W208 CLK 320 Cabriolet - Magma Red