Nico9182349

Hi there,

it is cold over here in Europe. Sometimes below 0C (32F).

The colder it is the more present I hear a wining noise when coasting after a cold start. When I touch the gas pedal it goes away instantly. It is not dependent on the gear I'm in either.

The noise is most noticeable between 40 and 55mph. It becomes inaudible above 55 and is inaudible below 40mph.

The sound goes away the warmer the car gets but when it is well below zero it can easily stay for 20 minutes or so.

Does anyone have an idea or has experienced the same? It would help me if I could give the dealership some pointers, since the conditions it arises are quite specific.

Regards

W205C43PFL

Sounds similar to this: https://mbworld.org/forums/s-class-w...-replaced.html

Nico9182349

I saw that one but the speed does not match and there is no mention of temperature dependancy and being able to stop the sound when you touch the gas pedal. The one that sounds very similar is this one https://mbworld.org/forums/c450-c43-...houghts-6.html but that is an entirely different car.

W205C43PFL

I see, sorry that I wasn't able to help. Hopefully someone else chimes in.

W205C43PFL

Let me try to help again : )
Can you tell me when did you notice does and does the frequency ever change the warmer it gets, you said when it is warm it disappears?

Nico9182349

The frequency of the noise changes with the speed I would say but when it is warmer I don't hear it at all.

W205C43PFL

It is loudest at what speed in particular or temeprature how many miles does your vehicle have? Does humidity affect the sound? Like for example if it is cold but is it rainning does the resonance change?

vinflouen

Cold bearings.
if you notice, Mercedes sound different in all weather.
check your pulleys and belts.

MBNUT1

Sounds like differential noise, based on the fact that it makes the most amount of noise coasting, goes away with throttle and is gear independent. My E350 is the same at about the same speeds as well.

Nico9182349

It is NOT dependant on gear

Nico9182349

Like I mentioned in my post, it is loudest between 40 and 55mph and temperatures below 0C (32F) and it does go away after some time. The longer the quieter the noise. Can't say much about humidity since it is usally dry when it is cold hear. It's at about 65000 miles right now.

cfmistry

Pop the hood, do a cold start, and listen to the belts / pulleys. I doubt this is the issue but it’s too easy to not check.

Next step would be to change the differential fluids. My rear was filthy at 72k miles - wish I’d done it sooner.

Nico9182349

Could be worth a shot actually. Not a bad idea. But did you actually hear any noises?

W205C43PFL

So sorry about that OP, I missed that information from your original post. I see, good to hear there are others that chimed in offered you advice that I never thought of, hopefully that solves your issue.

MBNUT1

That's what I meant by "gear independent". Which eliminates the engine and the transmission up to the output shaft and bearings.

I will add that I have had my transfer case rebuilt twice and front differential replaced with a lower mile used unit and my car makes a similar noise that is torque dependent as you describe which makes me think that it is pinion whine because it quiets down if I apply a little load.

Based on my experience IMHO Mercedes drive line components don't seem to be very robust.

JohnLane

Pinion bearing. Likely the front bearing. It is smaller and most inclined to wear. It is ready for replacement when it whines when warm too. Fresh synthetic gear oil can’t hurt but don’t expect that to make it quiet.

Nico9182349

Sorry, misread.

Pinion bearing, noted. That is not a part that can be exchanged on its own though is it?

MBNUT1

Well I am quickly getting out of my depth here. I tend to imagine it is the gear mesh because it quiets down when they get loaded up. Assuming this was the issue and somebody could put it up on a rack to see if they can hear it I suspect it could be rebuilt.

Nico9182349

Surely it could be technically done but the car is still under Mercedes Used Car warranty (Junge Sterne Garantie) and Mercedes would just replace it I reckon. The big question is - is it really the differential? And if so, is a noise under such specific conditions enough to justify a replacement. You would think so with a 150k car but the star is not as bright as it used to be. Will see. Got the appointment Monday in a week.

MBNUT1

Good luck and let us know what they find.

Nico9182349

I took the car to the shop as previously announced. It is NOT the differential, it is the tyres! My winter tyres started to make these really loud noises due to wear somehow. We swapped it to summer tyres and this morning was really cold so I just took it for a quick test ride and the noise is gone despite cold temperatures.
From this experience I must encourage W222 drivers to avoid Bridgestone Blizzak. It took one winter season for the flanks to go flat in the front and - as I know now - it started becoming ridiculously loud. Really bad experience.

W205C43PFL

They are good tires in terms of what they do, you could also try Nokian, they are a Finland company or you could always go back to Michelin.

Nico9182349

I think I will go with Pirelli since those are the tyres the car was delivered with from the factory.

Quenthel

I have the Blizzaks and haven't noticed anything of that sort. I'll try and pay more attention next time I get to my car, to see if I have the same issue.

Nico9182349

Mine have about 9000 miles on them. Maybe I'm driving them too hard and it caused quicker wear. I do think I recall that they made this noise from he beginning though, just not as loud.