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A Different '03 Manual A/C Noise

RichUF

SM 2005
Full Member
Joined
Jun 11, 2002
Messages
10,631
Well, at least I didn't find an existing thread that described this one. At low fan speeds (1 or 2) a swish swish swish sound can be heard, becomes gradually louder, then stops like an auto switch is tripped or something. It stays off for a few seconds, then repeats. It sounds like a gas being forced through a valve. Maybe this has something to do in the refrigeration cycle where the warm, low-pressure gas is compressed into a cold, high-pressure liquid?

Anyone else hear this? Is it normal or should I get it checked? It's only a minor annoyance, and everything else seems fine.

Thanks,
Rich
 
I suppose it could be the refrigerant expanding. It gets compressed by the compressor (obvious, huh?) then cooled by the radiator out front. From there, the high pressure liquid goes into the passenger compartment, where it goes through an expansion valve. This is where it expands into a gas and becomes very cold.

As this happens, it can make various gurgles and hisses. It might just be that it is happening all the time, but is only audible when the fan speed is low. At higher fan speeds it gets drowned out.

Of course, it's always difficult to diagnose sounds based solely on a description. If you are worried, let an A/C tech listen to it. They'll be able to tell you for sure if it's normal or a problem.

-- SS
 
I think this A/C system - like many recent model systems - uses a compressor cycling system, i.e. the compressor runs until the suction line pressure reaches some point and then it shuts off . . turning itself back on when the pressure rises again. ?My guess is that you are hearing the refrigerant responding to this compressor cycling. ?You'll hear the most cycling with low demand on the AC system (as you said - fan position 1 or 2) - on a really hot day with the fan on hi, the compressor will run all the time and you won't hear the cycling related sounds.
 
I had this noise officially checked into since my Av is in the shop to have the now-infamous auto 4WD transfer case fixed. The verdict is that it is gasses like we suspected here and that it is NORMAL :cautious:

So what I now want to know is do any other '03 owners with the manual A/C system hear what I am describing? I'll consider it normal just as soon as others confirm that they hear it also. To put it into type, it is something like shhhk shhhk shhhk shhhk shhhk shhhk shhhk shhhk... (pause)shhhk shhhk shhhk shhhk... about at a tempo/cadence of ~2-3 times per second.

Thanks,
Rich
 
I have the same noises and I too was informed that it's a normal noise. You hear it less at higher fan speeds.

 
I've heard the same kind of sound. Mostly coming from the passenger side vent (near door). It sounds like air leaking. It's normal and sometimes distracting.
 
Thanks, guys, that's all I needed to hear to close this issue for me. Sounds like something that GM can maybe work on for next model year because it is annoying if you don't have the radio on or something.

Rich
 
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