michail71

I think the fluid is fine. The car is warm as it was driven a few hours ago. The fluid was between the hot and cold markings. I will see where it is in the morning once the car has cooled down some more.

Turning the wheel is fine and produces no additional noise or vibrations and the steering is smooth. The only thing that changes is pitch and volume with RPM. With the stethoscope rod pressed against the pump body I hear a whirling grinding kind of sound. I would almost say it sounded like bits of something were rattling around.

michail71

Actually, the reservoir is on the opposite side of the hood, kind of over the turbo intercooler piping. It seems odd to me that they are so far apart.

So far this is the second thing I've found that two dealers over multiple trips have missed.

michail71

I think the fluid is fine. It's above the full line for cold and below the low line for how. The temperature at the times was about 80F/27C.

I'll see if I can rig a way to record what I heard from the scope. If I can get a metal rod to my phone microphone it may work.

cvx5832

I had a 2013 C250 rental with around 10k miles for a couple weeks. It didn't have a whine, but it did have a cyclic knock that stayed the same hot or cold. It sounded like rod knock to be honest. It was a punchy motor however and overall I remember being impressed. What a gorgeous engine. First time I tried a turbo.

I couldn't help but look inside, and found it irresistible to top off the oil.

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c3002008

Hi,
What ended up being the issue with your car?

pezzy669

My '09 has a deep whine at low speeds, high RPM (WOT to redline) has a more turbine like higher pitched whine/whistle.

I'm not too terribly concerned about it as it is not objectionable. I'm sure if I invested in all new engine/tranny mounts and new flex discs it would probably go away but yeah I'm not spending that $$$ on a 8 year old car.

Adi-Benz

Why do our cars whine when we drive slowly?

No other car I have owned has made this many noises. Nothing wrong with it but weird af.

superangrypenguin

How about a car with a suprecharger?

Pinkrangerdaddy

Hi Michail71, excuse me for reviving an old post, I read your every single posts within this thread and I have the same exact situation that you were talking about, did you manage to get it fixed already? I went to two indies and they tell me it is normal, it is not normal as we have 2 C250 CGI at home and the other one is does not whine, please help me!

It appears to whine after we changed the AC Compressor with a refurb unit, that could be the culprit? I really do not know =(

michail71

I have just gotten sort of used to it by now. I've noticed it in other C250s as well. They all have the same sound but it can be lounder in some cars more than others.

I tend to be overly sensitive to these things but it could be you are getting a louder version from the AC compressor or any other pulley or tensioner.

Pinkrangerdaddy

Any chance you installed audio amplifier in your car?

michail71

No, I have just the stock setup with Comand.

Matt Early

superangrypenguin

My C300 only whines when my steering is on full lock....

adro92

I have a 2008 C180 Kompressor, it used to whine when cold. Or more like chirp. I took it to my local MB shop and they replaced the belt tensioner. Now it doesn't whine or chirp anymore, it's very quiet, no noise on full lock or anything like that.

DrivingForce

For those of you that had success replacing your alternator to get rid of the noises, did you also have to replace the voltage regulator?

DrivingForce

FYI I replaced the alternator. It made no difference in the whining!!