EngHH

Hi Guys,
I have a weird Whirring noise coming from the bottom of passenger seat, maybe a wheel bearing? The volume of the noise increases with speed.
See attached video.
Any and all advice will be highly appreciated.
Thanks

nyMBdriver

Does the sound go away when you turn the HVAC off?

I might have the same issue as you had. It's just a bad blower motor. Easy fix. You could either replace it or try to lubricate it.
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EngHH

Hi,
Thanks for the reply.
No, the sound stays on despite HVAC off. I think its related to the axle at the front right wheel...
Not related to Belt i dont believe either
Thx

alecmascot

Check the cv joint boots in case you have lost the grease.

gwai_jai

Sounds like the sound I had when my transfer case went bad and your video had to same symptom that I was experiencing where it got louder after 50km/h and it was speed related, not RPM.

Colin G

EngHH, have you ever had the 4 matic transfer case fluid changed? It is not a lifetime fluid.

I had mine changed at 68,000 kilometers to avoid any chance of my 4-matic transfer case bearing going, which is what may be happening to your car.

Dougmay

Thanks for your suggestion! My 2010 C250 4 matic has just begun making transfer case noise at 55,000km. I took it to my BCAA mechanic who diagnosed the noise with a stethoscope. He spoke with Mercedes re parts and reported back to me that Mercedes said it would be a $10,000 repair as they would have to replace the transmission(!)

I will take the car to my dealer for a second opinion and discuss a transfer case fluid change.

Narry

hi
well i had a same problems when i change my pickup transfer case oil i put a lsd anti friction oil buy from amazon and problems solved i fail to understand why needed replace the transmissiom please try this first
narry

Dougmay

Thankr you Narry!

Aschofie

Good afternoon all,

Did the fluid change in the transfer case solve the issue?
I have a 2008 C300 4Matic with 250,000km on the odometer and I'm getting a somewhat similar sound, similar location, speed dependent, just WAY quieter; it's almost a whirling fluttery sound from about where the passenger's left knee would be, under the car. When driving above 40km/h, the sound becomes audible, but just. The sound doesn't get much louder as I drive faster, the frequency just increases with the speed (way faster than the drive shaft turning - I grew up with trucks, so a squeaky U-Joint was a common sound). The sound is still present if I'm driving and put the transmission into neutral. There's a split second of no sound when I shift to neutral, then the sound comes back at a slightly higher pitch like there's no load on it. The sound doesn't change much when I turn or put pressure on one side of the car, vs the other side.

I'm a stickler for proper maintenance, so I follow ALL maintenance intervals exactly (with exception to oil changes, because oil lasting 20,000km is B.S., so 10,000km it is), and when MB says it's "good for the life of the vehicle" I call B.S. and make up my own maintenance interval to follow (i.e. power steering flush - 100,000km, differentials - 160,000km, etc.). I have my transmission serviced every 55,000 - 60,000km and do a drain and fill on the transfer case at the same time, every time and have them clean off the magnet.
I first thought I was low on fluid, but the transfer case is clean/undamaged (serviced approx. 25,000km ago with the transmission) and I don't get that deep humm you'd get from a transfer case low on fluid. This is a light fluttery sound, similar to the video, but much, much quieter. I also checked the 'big ticket items' like the front differential, even though it's not exactly where the sound is emanating, and it's clean/undamaged. Transmission is clean/undamaged, flex disc looks used but not cracked (this would not make that kind of sound). I need new wheel bearings, but they make their own sound (I can hear them).
What I've checked so far:
- Front differential - no external damage or leaks
- Transmission - no external damage or leaks
- Transfer case - no external damage or leaks (no slipping/popping/jumping either when I stomp on it)
- Flex disc - not cracked or significant damage
- There is no additional vibration in the car
- Steering and power delivery is just fine (these Germans know how to make a car, I'll tell you that much)
- Nothing rubbing on any drive shaft or CV axle (I crawled underneath and followed the driveline from front to back)
- CV axles are in good condition, although this is not a clicking sound and doesn't change with turning the car (passenger side was repacked and had a new boot approx. 40,000km ago, driver side blew up on my about 20,000km ago, so it's new)
- U-joint on the front drive shaft connecting the transfer case to the front differential looks to be in reasonable condition, but this isn't a squeaking sound.
- Brake components are firm and don't rattle around - although I can use new front pads in the near-ish future.
- lug nuts are tight
- Other than my PCV seal, there are no leaks or damage that can be found.
- My cabin ventilation fan has a loose impeller vane or two and it gently touches the housing. This is a similar sound but not the same. Also happens when the vents are off.

I've taken to YouTube, listening to what different vehicle driveline components sound like when they fail, and I'm at a loss here.
Any ideas?

EngHH

it was the wheel bearing for me. Fixed and noise gone. Still driving it today but my ignition switch died, turning it on from the hood until I can buy another car lol.

Aschofie

Thanks!
For the ignition, get an emulator. It’s the little device that makes noise when you insert the key? Mine died in me in 2012 and then again in 2019, so I put in an emulator and I’ve never had an issue.

EngHH

it’s actually the ignition switch. You could get an aftermarket one in the past but with all the car theft now you need to get it from the dealer. It’s too expensive > than value of car.

I hope you can fix your issue.