AC Noise..Please Help
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AC Noise..Please Help
Why does my AC compressor emit a rather loud buzzing noise? The MB dealer has replaced the compressor once already but the noise remains; is there a valve of sorts that controls the compressor's pressure, as I've been told that the noise I may be hearing could be the compressor overcharging or charging too often?
Thanks
2004 CLK 500
Thanks
2004 CLK 500
Last edited by RJC; Dec 2, 2005 at 05:43 PM.
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From: HOUSTON, TX
'06 CLS55 P030
a/c comp. noise?
I have never heard of this condition. The buzzing is likly from the p/s pump---located right above the compressor. These a/c comps do not have a clutch like a standard compressor--variable displacement is the type. They really dont fail often.
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From: 2000 ft over the FL coast in a B-17
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Thanks for the reply. It's not the power steering pump as that's been checked by MB already.
The noise only occurs when the AC is turned on, the AC works very well but the compressor emits a very loud buzzing sound (similar to what a neon sign sounds like) for most of the time the AC is on; it gets especially loud right when turning the AC off then the sound goes away completely, about 10 seconds later.
What part(s)could be causing the compressor to overcharge/over pressurize?
Thoughts are most welcome as this has been occuring since the car was brand new.
The noise only occurs when the AC is turned on, the AC works very well but the compressor emits a very loud buzzing sound (similar to what a neon sign sounds like) for most of the time the AC is on; it gets especially loud right when turning the AC off then the sound goes away completely, about 10 seconds later.
What part(s)could be causing the compressor to overcharge/over pressurize?
Thoughts are most welcome as this has been occuring since the car was brand new.
Last edited by RJC; Dec 5, 2005 at 03:15 PM.
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From: HOUSTON, TX
'06 CLS55 P030
RJC I have done some research and have found nothing. I checked dtb's. I checked another clk and it sounded o.k....a slight whine-buzz is heard, mainly when cold, and is said to be operating as designed. I would say....wait till it fails...if it ever does. If the car came new...having this noise and having no repairs or bodywork..probably nothing is wrong with it.
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From: HOUSTON, TX
'06 CLS55 P030
Originally Posted by liz
I have a deep whing sound in my a/c. whenever it's on and the car is accellerating (especially 1st to 2nd to third) it whines. The sound is similar to a whining transmission. Nobody has been able to rectify this.
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Originally Posted by 516mbtek
RJC I have done some research and have found nothing. I checked dtb's. I checked another clk and it sounded o.k....a slight whine-buzz is heard, mainly when cold, and is said to be operating as designed. I would say....wait till it fails...if it ever does. If the car came new...having this noise and having no repairs or bodywork..probably nothing is wrong with it.
Thanks
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Senior Member
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From: HOUSTON, TX
'06 CLS55 P030
a/c comp pressure control
The pressure is controlled by the control valve (solenoid) on the side of the compressor. The control valve is given a pwm signal according to various inputs to the a/c control panel...inputs:all temp sensors, humidity, sun, evap temp, and engine coolant temps. hope this helps
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From: 2000 ft over the FL coast in a B-17
Various
Originally Posted by 516mbtek
The pressure is controlled by the control valve (solenoid) on the side of the compressor. The control valve is given a pwm signal according to various inputs to the a/c control panel...inputs:all temp sensors, humidity, sun, evap temp, and engine coolant temps. hope this helps
Thanks again 516 mbtek!
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Lexus
My S500 does it also, so did my last one. It sounds like the bearings or valves in the compressor. The air always works fine.. It is annoying, and very noticable when you drive away from a drive through window with they air on. I figured that the A/c compressor replacement would cure it. Did you get a new ac compressor or a Remanufactured one??
Scott
Scott
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From: 2000 ft over the FL coast in a B-17
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Originally Posted by williws
My S500 does it also, so did my last one. It sounds like the bearings or valves in the compressor. The air always works fine.. It is annoying, and very noticable when you drive away from a drive through window with they air on. I figured that the A/c compressor replacement would cure it. Did you get a new ac compressor or a Remanufactured one??
Scott
Scott
. I also heard a W203 make the exact same noise at a 7-11, but I never had this on any otherMB's I've owned.
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From: HOUSTON, TX
'06 CLS55 P030
Originally Posted by RJC
Thank you. Is the control valve a permanent part of the compressor or is it a detachable part that may not have been changed when MB switched out my compressor? If the control valve is a permanent part of the compressor and it was therefore changed with the replacement compressor, what else should I be looking for causing my compressor to pressurize too much/often?
Thanks again 516 mbtek!
Thanks again 516 mbtek!
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From: 2000 ft over the FL coast in a B-17
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Originally Posted by 516mbtek
The pressure control valve comes with the compressor. I would suspect incorrect version coding in the aac control unit or a faulty input signal. But, it is always likley that this may be a characteristic of this hvac system...and...well you have heard it before...normal operation for your climate//elevation//temp etc. etc.
Again thanks for the help. The W203 that made same noise was the only other MB that I've ever heard making this dreaded sound. I will ask my tech at the dealership to look into the items you mentioned. I also owned a 2003 CLK500 that had a very quiet and normal sounding AC. If you happen to come across any other info/ideas please let me know.
We appreciate having a resource like you @ this forum.
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From: HOUSTON, TX
'06 CLS55 P030
Originally Posted by RJC
Again thanks for the help. The W203 that made same noise was the only other MB that I've ever heard making this dreaded sound. I will ask my tech at the dealership to look into the items you mentioned. I also owned a 2003 CLK500 that had a very quiet and normal sounding AC. If you happen to come across any other info/ideas please let me know.
We appreciate having a resource like you @ this forum.
We appreciate having a resource like you @ this forum.
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my car is an 02 e320 4matic with a new compressor and radiator (accident). any help would be greatly appreciated. the noise is loud and constant. especially when the car has been running for 10 or more mins. my star mark warr. runs out in oct 06. we've been hoping the system would fail enough to be replaced as they simply cannot alleviate the problem. i try to keep the system off and long as humanly possible as it is so annoying. the kia cheapo rental had a quieter system. sorry for complaining, i am just very frustrated. again thanks for any info.
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From: HOUSTON, TX
'06 CLS55 P030
If the noise is that bad why cant they fix it? Who did the work... a bodyshop, dealer, independent? What are they telling you? That they cannot duplicate it..or its normal..or what? I recomend that u request to test drive with the tech and tell them what u want fixed. If the noise occurs ONLY with the a/c on, and it is coming from the engine compartment, and it is totally excessive..and they put a new compressor (complete unit I assume) they its likely...they forgot to put oil in the new compressor. Or the new compressor has failed for other reasons. If the noise occurs all the time, wheather a/c on or off...then it sounds like a p/s pump. Check the fluid w/ engine running...the p/s pump reservoir cap (black, drivers side) has a little dipstick. Oct 06 is a long way away...
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2 different mb dealerships worked on the car-many times. 1 said it was normal. the other replaced some pulley item. the problem occurs only when a/c is on. i did have the harmonic balancer replaced previously, and considered the issue possibly related (drier/ reciever or damper(something like that(?)- heard that somewhere on this website. i did drive the car with the sa to show him the issue, he found it to be exceesive. techs said nothing registered on the comp. relevent to the noise. however, the system is constantly 1/2 lbs low (3x in one season). dye was put into the system but no leak found (according to sa). i must bring the car back in again as there is ticking sound on drivers side of engine and the belt makes loud noise. I was just hoping to have a clue as to what this could possibly be. thanks again for helping.
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From: 2000 ft over the FL coast in a B-17
Various
I see there is a TSB (P83 55 65 Dec 02) for the 2002-2004 C class that ,mentions the AC compressor cycles too frequently; I wonder if this issue could be giving some of our problems?
Last edited by RJC; Dec 15, 2005 at 02:34 PM.
