Shrill Whine at Startup on Cold C55
Thread Starter
MBWorld Fanatic!
Joined: Jun 2012
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From: SF Bay Area
C55 AMG, 300D-T & Karmann Ghia
Shrill Whine at Startup on Cold C55
Ok, this isn't the usual M113 whine at startup...
Over the last couple days I noticed an incredibly shrill/high pitched whine when the car is started cold. It lasts about as long as the car takes to idle down to normal RPM, maybe a little longer. It is really loud and obviously not normal...
What I know is that it is coming from the front of the engine (or at least it sounds like it) The way it sounds when it quits is indicative of something 'powering down'- whatever component is making the noise is only active when the car is cold. It could be a pulley or something associated with the component. I'm really not sure what- so I was hoping for suggestions of where to look...
Thanks!!!
Over the last couple days I noticed an incredibly shrill/high pitched whine when the car is started cold. It lasts about as long as the car takes to idle down to normal RPM, maybe a little longer. It is really loud and obviously not normal...
What I know is that it is coming from the front of the engine (or at least it sounds like it) The way it sounds when it quits is indicative of something 'powering down'- whatever component is making the noise is only active when the car is cold. It could be a pulley or something associated with the component. I'm really not sure what- so I was hoping for suggestions of where to look...
Thanks!!!
Super Member
Joined: Jul 2009
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2021 Yukon XL Denali, 2017 GLS450 4MATIC, 1993 Chevy Corvette
Search for idler pulley noise. It might be the bearing going bad. Happens to the 3.2 engines not sure about the 5.4. Pulley is cheap for the 3.2 and easy to do yourself.
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Joined: Oct 2012
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'07 CLS 63, '91 E34 M5 Dinan Stroker
I bet it's your air pump. I hear mine at cold start for about a minute then as you describe it "winds down". Mine is more of a high pitched electric sound. Pretty quiet actually. I have this in my 91 M5 also and for a while it sounded like a jet APU running. Really loud. Maybe yours is going bad,
Thread Starter
MBWorld Fanatic!
Joined: Jun 2012
Posts: 1,155
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From: SF Bay Area
C55 AMG, 300D-T & Karmann Ghia
that sounds about right - electric sounding; high pitched and steady then almost 'powering down' once the car has some heat
It did it again for a moment when I got to the parking spot after 10 min, only for a second.
How much is this gonna cost me?
It did it again for a moment when I got to the parking spot after 10 min, only for a second.
How much is this gonna cost me?
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Thread Starter
MBWorld Fanatic!
Joined: Jun 2012
Posts: 1,155
Likes: 4
From: SF Bay Area
C55 AMG, 300D-T & Karmann Ghia
MBWorld Fanatic!
Joined: Jun 2009
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From: Atlanta Metro
Current: C217 V12TT AMG Previously: C55 AMG, SL65 AMG
For over a year now, maybe two, I have the very same high pitched whine, in addition to the regular air pump noise. No problems here
Thread Starter
MBWorld Fanatic!
Joined: Jun 2012
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From: SF Bay Area
C55 AMG, 300D-T & Karmann Ghia
An update: It is in fact the air pump up front. With the front engine cover off it was right there and apparent the sound was too. I grabbed the damn thing while it was shrieking and choked the life out of it. Seriously though, a bump or two and the sound changed to a much quieter, almost normal noise.
I'm gonna leave it be for now and see if I can milk it a few thousand more miles. Thanks all for your help-I'll update if it starts acting up again.
Have a good weekend!
I'm gonna leave it be for now and see if I can milk it a few thousand more miles. Thanks all for your help-I'll update if it starts acting up again.
Have a good weekend!
Thread Starter
MBWorld Fanatic!
Joined: Jun 2012
Posts: 1,155
Likes: 4
From: SF Bay Area
C55 AMG, 300D-T & Karmann Ghia
yeah, mine would change pitch and intensity when I took the cover off and fooled around with the pump itself. I have gone a couple days with it silent, so the front engine cover is going back on!
it will start squealing again when i take a BMW buddy out, no doubt :P
it will start squealing again when i take a BMW buddy out, no doubt :P
Member
Joined: May 2012
Posts: 112
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From: Virginia
05 C55
Have any of you been able to successfully remove the AIR pump from the system entirely? Or at least not have it functioning? That sound totally kills the lovely noise of a high performance V8 starting up when cold.
Damian
Damian
Thread Starter
MBWorld Fanatic!
Joined: Jun 2012
Posts: 1,155
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From: SF Bay Area
C55 AMG, 300D-T & Karmann Ghia
I haven't had to do it since mine has quieted down, but I did read that people where able to shut it off at the cost of an emission fault. Not sure how, but it doesn't seem to be belt driven so it should be easy.
