Aircon Noise - PeachParts Mercedes-Benz Forum

skyluck2001 · #1 11-26-2006, 12:05 AM

Hi All,

I own a Mercedes 200E 1990 model with 350,000km.

Recently, my aircon keeps making intermittent noises - soft hissing and loud pant/sneeze while driving. I presumed these noises are made by my aircon because they disappear whenever I switch the aircon off. These two types of noises occur independently of each other.

When the loud pant/sneeze occurs (as if releasing a gush of air), the car would feel a slight jerk/strain and my oil pressure would dip slightly before rebounding. This jerk/strain and oil pressure dipping does not happen when the aircon hisses softly though.

What could possibly be the reasons for these different noises and what should I do to rectify them?

Thanks and best regards,
skyluck2001

sixto · #2 11-26-2006, 12:19 AM

Could be as simple as low refrigerant. Have someone with a good set of gauges check your system.

Sixto
93 300SD

skyluck2001 · #3 11-27-2006, 07:20 AM

[QUOTE=sixto;1340057]Could be as simple as low refrigerant. Have someone with a good set of gauges check your system.

Thanks. Will try your suggestion.

Cheers

James L · #4 11-27-2006, 03:51 PM

do not use your a/c until you have this checked out! could be a belt that needs repacement or adjusting BUT, if it is low on refrigerant, do not just add refrgerant, you need to know why. If it has a leak it needs to be found and repaired. you want a leak free system so as not to loose oil and of course refrigerant. oil is carried with the refrigerant and when there is a leak the oil/refrigerant combo goes out of the leak spot. eventually the compressor gets starved for oil and makes noises, seizes, breaks belts, ect....then you have to dissassemle and flush everything along with a new rec/dryer compressor expansion valve.... ask me how i know! .... LOL..

skyluck2001 · #5 11-28-2006, 04:57 AM

Quote:

Originally Posted by James L

do not use your a/c until you have this checked out! could be a belt that needs repacement or adjusting BUT, if it is low on refrigerant, do not just add refrgerant, you need to know why. If it has a leak it needs to be found and repaired. you want a leak free system so as not to loose oil and of course refrigerant. oil is carried with the refrigerant and when there is a leak the oil/refrigerant combo goes out of the leak spot. eventually the compressor gets starved for oil and makes noises, seizes, breaks belts, ect....then you have to dissassemle and flush everything along with a new rec/dryer compressor expansion valve.... ask me how i know! .... LOL..

Just had the aircon checked by a MB mechanic. He says that nothing is wrong with my aircon system, refrigerant is not low, and that it is normal for the aircon to rob some power.

The car behaved well today, with and without the aircon, so the mechanic did/could not get to hear the noises. That really is the frustrating part, the hissing and sneezing sound only appears on some days. Other times, the car runs fine and she is a joy to drive.

Well, at least I'm consoled that my aircon system isn't leaking or shot. I had soft hissing noises in my previous car without giving rise to any problems, so I'm not overly worried. However, the loud sneezing sound is something new, and the MB guy speculated it could have come from the expansion valve.

Any idea what is causing that sneezing sound? Thanks.