Long Term Whine from Air Conditioning
Thread Starter
MBWorld Fanatic!
Joined: Mar 2008
Posts: 3,714
Likes: 56
From: 1 hours drive north of Sydney Australia
2007 W204 220CDI Classic Sedan
Long Term Whine from Air Conditioning
I have had a high pitched whine in my A/C for over two years .
Initially I thought it was from the ATM as the sound changed with gear changes but a change in engine revs is also accompanied by gear changes.
The symptoms are :-
1.Whine only occurs with A/C in service.
2. Whine stops 50 seconds after A/C is switched off.
3. Whine occurs when A/C is lightly loaded eg. a cool day & low setpoint.If the A/C is made to work the noise disappears.
4. It is intermittent with the A/C in service.
5. The whine tone changes with rpm change.
6. The system performs perfectly.
I am wondering whether there is a harmonic of some sort associated with the A/C vanes & the throttling of the gas in the compressor.
It usually stops when the car is stationary & before I have a chance to lift the bonnet & use a stethescope
I would be grateful of some advice & to know whether anyone else has experienced this noise.
Initially I thought it was from the ATM as the sound changed with gear changes but a change in engine revs is also accompanied by gear changes.
The symptoms are :-
1.Whine only occurs with A/C in service.
2. Whine stops 50 seconds after A/C is switched off.
3. Whine occurs when A/C is lightly loaded eg. a cool day & low setpoint.If the A/C is made to work the noise disappears.
4. It is intermittent with the A/C in service.
5. The whine tone changes with rpm change.
6. The system performs perfectly.
I am wondering whether there is a harmonic of some sort associated with the A/C vanes & the throttling of the gas in the compressor.
It usually stops when the car is stationary & before I have a chance to lift the bonnet & use a stethescope
I would be grateful of some advice & to know whether anyone else has experienced this noise.
MBWorld Fanatic!
Joined: Feb 2004
Posts: 3,986
Likes: 6
From: SEATTLE WASHINGTON USA
'08 C300 Lux Barolo Red Beige Leather P2 MM 18" wheels '84 944
I have had a high pitched whine in my A/C for over two years .
Initially I thought it was from the ATM as the sound changed with gear changes but a change in engine revs is also accompanied by gear changes.
The symptoms are :-
1.Whine only occurs with A/C in service.
2. Whine stops 50 seconds after A/C is switched off.
3. Whine occurs when A/C is lightly loaded eg. a cool day & low setpoint.If the A/C is made to work the noise disappears.
4. It is intermittent with the A/C in service.
5. The whine tone changes with rpm change.
6. The system performs perfectly.
I am wondering whether there is a harmonic of some sort associated with the A/C vanes & the throttling of the gas in the compressor.
It usually stops when the car is stationary & before I have a chance to lift the bonnet & use a stethescope
I would be grateful of some advice & to know whether anyone else has experienced this noise.
Initially I thought it was from the ATM as the sound changed with gear changes but a change in engine revs is also accompanied by gear changes.
The symptoms are :-
1.Whine only occurs with A/C in service.
2. Whine stops 50 seconds after A/C is switched off.
3. Whine occurs when A/C is lightly loaded eg. a cool day & low setpoint.If the A/C is made to work the noise disappears.
4. It is intermittent with the A/C in service.
5. The whine tone changes with rpm change.
6. The system performs perfectly.
I am wondering whether there is a harmonic of some sort associated with the A/C vanes & the throttling of the gas in the compressor.
It usually stops when the car is stationary & before I have a chance to lift the bonnet & use a stethescope
I would be grateful of some advice & to know whether anyone else has experienced this noise.
Long out of warranty, right?
Thread Starter
MBWorld Fanatic!
Joined: Mar 2008
Posts: 3,714
Likes: 56
From: 1 hours drive north of Sydney Australia
2007 W204 220CDI Classic Sedan
Yes, out of warranty for 2 years but I did complain about it before it came out & the mechanic took it for a test drive without the whine reappearing!.
Thread Starter
MBWorld Fanatic!
Joined: Mar 2008
Posts: 3,714
Likes: 56
From: 1 hours drive north of Sydney Australia
2007 W204 220CDI Classic Sedan
Ah Ha ,others have experienced the dreaded whine !!
http://www.benzworld.org/forums/x164...sor-noise.html
http://www.benzworld.org/forums/x164...sor-noise.html
Super Moderator
Joined: Jun 2008
Posts: 19,942
Likes: 192
From: Llandudno, Cape Town, South Africa
late 2009 CLK 350 Coupe Elegance, '65 Jaguar S Type wires
Interesting. Would certainly seem to be the compressor. The one on my M272 is dead quiet. I wonder if one can retrofit the muffler?
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Joined: Jul 2007
Posts: 1,351
Likes: 90
From: Germantown, MD/Rehoboth Beach, DE
2024 GLS450
Mine has this. I have complained twice and been told it was normal turbo noise. They couldn't explain to me how my turbocharger is connected to the A/C function on my climate control however 
. The damn thing screams louder than my engine, like a Roots type supercharger at high RPM.
Looks like I have more ammo for them to fix it come spring. The A/C on my $16k smart was never this noisy, and I was nearly sitting on top of the compressor.
. The damn thing screams louder than my engine, like a Roots type supercharger at high RPM. Looks like I have more ammo for them to fix it come spring. The A/C on my $16k smart was never this noisy, and I was nearly sitting on top of the compressor.
Thread Starter
MBWorld Fanatic!
Joined: Mar 2008
Posts: 3,714
Likes: 56
From: 1 hours drive north of Sydney Australia
2007 W204 220CDI Classic Sedan
Mine has this. I have complained twice and been told it was normal turbo noise. They couldn't explain to me how my turbocharger is connected to the A/C function on my climate control however . The damn thing screams louder than my engine, like a Roots type supercharger at high RPM.
Looks like I have more ammo for them to fix it come spring. The A/C on my $16k smart was never this noisy, and I was nearly sitting on top of the compressor.
. The damn thing screams louder than my engine, like a Roots type supercharger at high RPM. Looks like I have more ammo for them to fix it come spring. The A/C on my $16k smart was never this noisy, and I was nearly sitting on top of the compressor.
Thanks also RLE & Glyn for your input.
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Super Moderator
Joined: Jun 2008
Posts: 19,942
Likes: 192
From: Llandudno, Cape Town, South Africa
late 2009 CLK 350 Coupe Elegance, '65 Jaguar S Type wires
W204 Denso Compressor
This should be the compressor fitted to the W204. The rotary valve & silencing chamber are built into the casing as best I can ascertain. No retrofit possible. The system should not make a noise.
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Member
Joined: Nov 2012
Posts: 134
Likes: 4
From: Montreal
C350 2010, BMW 325i 2001, Porsche turbo 996 2002.
May be not related but on my BMW 325i as soon the freon (r134) level is getting low I got this whining sound. After filling it to the maximum pressure (52 pounds) the sound is completely gone....
MBWorld Fanatic!
Joined: Nov 2007
Posts: 2,078
Likes: 4
From: NYC
2012 C300 4Matic
My W203 always did this and I assumed it was normal. Our W211 also does it. My W204 does it, but much less noticeably. Never had a problem related to it in any of the cars. I think it is probably a normal sound, even if not on all vehicles. Depends upon the volume though. On The E and the older C it is very noticeable, in the exact situation you mention - running at a light load, in the lower RPMs, and variable with RPMs. Sometimes it is louder than others.
