Bosnia1992

Hello,

I've been having a whining noise upon acceleration usually up to 2000rpm and upon slowing down.

I've searched threads on this issue and none really clarified what it was , I took it to the stealership and they duplicated it but said it was normal?? they also showed me another c300 that made the noise , it looked like it came from a junkyard and was neglected .


I started noticing the noise awhile back, they said it can't be the transfer case since mine isn't a 4Mattic which doesn't have a transfer case ? the noise sounds like a whine from a supercharger or a plane lifting off ,landing in the distance. Can't hear it much when the car is in park.

anyone having this issue ? is it normal ? any idea what it could be ?



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Domm

I have the same issue and a few others on this forum have complained about it. The consensus seems to be a noisy alternator.

RuskiBenz

i have it also its common some cars do it my maxima did it also and lasted me fine till 150k miles but the advice i do have for you is stop looking for problems with your car TURN UP THE RADIO and enjoy!!!!! your like a Hypochondria with your car lol

Bosnia1992

I was thinking that's what it might be , problem is stealerships would prefer to do the least amount of work for an extended warranty


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Bosnia1992

that's just the thing though, I don't believe it is normal along with others on here, a 2000 dodge does not make the noise nor should it be normal . I do enjoy the car but in order to enjoy the car in my opinion, the car itself needs to be in order first.



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Michael8

I had a similar noise when I purchased mine a few months ago and it ended up being the rear differential. Hopefully this is not the case with yours but my noise was heard mostly when sitting in the back seat. I hope that helps

Bosnia1992

Thanks , anything helps really as long as I can bring up the results of others that have had the same problem with theirs to the dealership.


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kevink2

OP, is the 2000 rpm limit for all gears?

Could be the louder general noise above 2000 rpm may be hiding the original noise. If so:

I recently trouble shooted a noisy bearing sound in the front of a Blazer engine. I used a mechanic's stethascope (~$5 @ HF) to isolate the sepentine belt tensioner pulley, which was an easy fix.

.

Bosnia1992

I don't believe so, the louder noise would roar not sound like a supercharger. its more of a whine noise . I should mention that they changed all of the pulleys, tensioners .


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Bosnia1992

not sure why your other comment is not.showing up but just ask them to put vibration sensors on the transmission?


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kevink2

Ok, normal accelerating from a stop using manual shifting at 3000 rpm:

1) does the noise increase in intensity or frequency as the revs increase ?

2) does the noise quickly stop as you pass 2000 rpm ?

3) is the noise the same in each gear

You mentioned a supercharger sound. I've heard a few but the most noteable was a V6 type on a dyno with a whipplecharger. The sound was defening and screaming as if it had a very high betorque load with high speed strait cut and dry speed increaser gearing.

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Bosnia1992

I will post a video in the next 20 minutes


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Bosnia1992

Would not let me upload the video so try this link
https://www.dropbox.com/s/w42uga8sll...2016.29.30.mp4

Bosnia1992

anyone have an idea now ?


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kevink2

the 1st part 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.


It's obviously not the differential. Any mods?

1) is the noise the same on the road

2) is the noise the same in each gear

.

Bosnia1992

no mods ,

1) yes completely the same

2) I believe after the 3rd or 4 th gear the noise almost disappears.

I spoke to my dealership today they contacted MBUSA and wanted a tech to come down and look at it. MBUSA refused to come down, they said it was a TSS Tech who refused because its normal ? yet I just started noticing it get louder after they fried my car at the dealership. I don't believe they've done any testing on the alternator , transmission , engine etc other than rev'd it and said it was normal nor did I receive any inovoice stating any diagnosis they did that day they had it.





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Bosnia1992

anyone have any insight ?


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kevink2

repeat of prior reply.

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Bosnia1992

ill post a clip of that tomorrow morning


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DonjuanOriginal

My issue was my power steering pump. An MB dealer told me its normal also. its bullcrap. got it fixed noise went away. good luck


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Bosnia1992

There's nothing normal about it. Dodge doesnt make the noise, kia doesn't. yet its normal for our Mercedes ?




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Bosnia1992

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

there you are.

kevink2

Thanks.

I think your noise peak is at about 2400 rpm, and it dissapears at 2500 rpm. Strange, but I suspect it is related to running at no load and high manifold vacuum. Like on the road, if you can manually hold it in 4th gear and 1500 rpm, and do the same moderate accelleration as this ramp up, rpm wise, I bet the noise will dissappear.

I have not checked the details, but there is a high vacuum bypass around the throttle body, and that path may be related.

Sorry but there is no simple answer from me. But, you might go to a cpo place and test drive and compare noises at idle with a 3L of your vintage .... what year? ... look below :


--------------------- *** All Members, New and some Old *** ---------------

please click on User CP at the top left of page, just below the thread title. Then add the following to either Profile and/or Signature , selecting buttons on the left side of that page:

year, model, if it's a diesel, Sport or Lux, 4MATIC or RWD, Location (city & state), and non-US country if applicable.

This helps others respond to issues, like tires, spring options, part sales, etc. Thanx

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Bosnia1992

They only had a 2008 that someone else brought in for repairs to show me the same noise..

What are you suggestions of what i shall do ?

kevink2

1) listen to a 3rd car from a dealer in MB CPO's, during a test drive.

2) if you hear it again, it is normal. Time to take your mind off it, as the dealer is not treating you badly.

At the beginning, you said it was during acceleration. The videos were run in park, with no load. I think the noise from speed and engine power transfer would make this a less significant noise, no?

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