NOISE ISSUE
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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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.
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Originally Posted by 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.
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.
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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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Last edited by kevink2; Mar 29, 2013 at 02:33 PM.
https://www.dropbox.com/s/w42uga8sll...2016.29.30.mp4
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
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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
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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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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
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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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Last edited by kevink2; Apr 1, 2013 at 02:45 PM.
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
.
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 ?
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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