gannee2001

Hi all,

I've been having a problem with my 2009 c300 4matic which Mercedes can't seem to find the cause of. Had the transfer case and transmission replaced under warranty. Had the windshield replaced as well.

Problem: High pitched engine whine upon acceleration at 2000 rpm. Happens everytime around 2000 rpm and disappears when I take my foot off the gas. It is barely discernible but is very annoying.

Thanks. Any suggestions would be appreciated.

Glyn M Ruck

If you rev the vehicle stationary & obviously out of gear can you repreduce the sound?

Best case scenario is a belt tensioner. Worst is a Torque converter or transmission oil pump or both.

BTW - the transfer case is integral with the transmission.

Glyn M Ruck

Can you post a clip?

C300BLK

Damn man, I have the EXACT same problem. Don't know what it is and MB says they can't find out whats causing it. It only happens sometimes for me though. It sounds almost like an F1 car when you let off the gas if we are thinking of the same sound. I don't think its the engine noise. I think it might have something to do with the tires or wheels but not exactly sure.

BEEPbeepZIPtang

Power steering pump...OR the power steering pump PULLEY.

JUST had mine done...1 month out of warranty...they dealership actually fixed it for free.

$120 part...was on my way out to preform the service at my house when my service guy asked if i wanted to pull the car around and they'd put it on...took'em 25 mins.

whine gone instantly...good luck!

DonjuanOriginal

Thanks have the same sound. Now i know what to complain about.

AuZZZie

I could have sworn I saw a WIS document on this and the fix was a redesigned accelerator arm or something along those lines.

hawknight

Did you find any solution to your problem? Any update? TIA

c3002008

Hi,
Could you explain the whine of your vehicle you had? Was it upon acceleration?

DonjuanOriginal

I replaced the whole pump assembly. pulley included. it made noise on accelerating and idling and turning the steeeing wheel. possibility the ps pulley fixes it. but I did the whole thing at once. good luck.


Posted from Mbworld.org App for Android

Bosnia1992

Hello Glyn,

Sorry to bring this post back up but my updated post is getting very little answers . Here's a clip of my 08sport making this noise, dealer states it's "normal" also states my power steering being extremely loud is normal as well .


link to video

https://www.dropbox.com/s/k2tvyi0za9k44k5/VIDEO0001.mp4

kevink2

Originally Posted by kevink2:

"the 1st part (of the video) was the most interesting. I think I can hear it as the revs increase over 2K. If possible repeat it with same slow increase in revs, but don't stop or delay until 3500-4000 rpm. A couple of accelerations will do."

I asked twice before, for the third and final time, how about doing something other than typing !

.

Bosnia1992

Sorry for the delay. Here's the link to that video .



https://www.dropbox.com/s/cd0aojbkwhdjkfo/VIDEO0002.mp4

Ikester

Mine does that sound too usually when accelerating at low speeds like on back roads. The car is RWD

Bosnia1992

Here's a TSB i found on alldatadiy.com

Replacement of Refrigerant Compressor Belt Pulley Due to Noise Complaints If you receive customer reports in the above model vehicles of noises at the refrigerant compressor with air conditioning activated and deactivated, the cause could be a defective belt pulley or belt pulley bearing. The pulley and pulley bearing can be diagnosed and replaced with the compressor still installed in the vehicle by following the procedures below.
1. Locate the noise by duplicating the conditions under which the complaint occurred.
2. If there is also a cooling performance complaint, the noise could be caused by low refrigerant level, perform a Refrigerant Circuit Test as per SDS and follow instructions for corrective actions.
3. Before the belt pulley on the refrigerant compressor is replaced, verify that the following components in the belt drive are not the source of the noise and repair as required.
^ Alternator
^ Power steering pump
^ Guide pulleys / tensioner pulleys
^ Water pump
4. If there is a whining noise that is RPM-dependant which is present with the air conditioning on AND off and is determined to be caused by the tensioner pulleys, guide pulleys or refrigerant compressor, continue with step 5.


I would assume it's the alternator, power steering pump or water pump then.

Ikester

Thanks for sharing do you have a mercedes TSB number we can reference to the dealer?

Bosnia1992

s-83 55-87 f

ithink thats correct


Posted from Mbworld.org App for Android

Ikester

Heres how my 2011 C300 sounds like:

http://www.youtube.com/watch?v=7fovQ...ature=youtu.be

Windows are up due to windy day.

Binhly101

Don't mean to bring up an old thread, but I noticed a whine on my car similar to what you described. I took the car into the dealership thinking it was prob power steering but my dealership called me today and said I needed a new transmission and transfer case...under warranty...thank god.

c3002008

Hi,
What ended up being the issue?

robnyc

I have a whine noise as well upon accelerating once i let go off the accelerator its gone.
I took it to my mechanic (not dealer) and they think its the idle pulley, searching here I thought it was either idle pulley or alternator.
Mechanic called me back saying its Air Compressor thinking here

Bosnia1992

If you are all experiencing this whine upon acceleration. It's most likely due to the transmission, they've changed all the pulleys in mine more than once and then eventually told me to "**** off " politely by stating it's normal now. Or they can't reproduce the noise because they don't drive this car daily to tell a difference anyways. Best bet if you're in warranty, take it to a reputable dealer who's willing to acknowledge the issue and not talk to you as if you just got into YOUR car and don't know from normal to abnormal. Or, go to a trustworthy Indy shop and spend a couple hundred to get the issue diagnosed truthfully.

robnyc

In my case I have the whine noise only upon accelerating and sometimes idle when i first turn it on, but if im already driving the car and i hold on the brake the noise goes away.
I thought it was the idle pulley or alternator as well, then i started reading this link and noticed I had issues with my windows defogging properly too.

https://mbworld.org/forums/c-class-w...ompressor.html

Carsy

I have had a whine for 3 1/2 years which is only heard when the air-conditioner is on & only under light load. On a hot day ie 34'C it is not present.

The whine sounds very rpm dependent ie raises & lowers the pitch.

It takes about 40 seconds to disappear when the A/C is turned off but disappears immediately when the set point is lowered.

Sounds like a gas/ liquid throttling noise to me, not mechanical.

Any advice welcome.

robnyc

AC compressor replaced thru my mechanic and noise is gone.