A/C problem?

[peeeot]

I have a 1995 Camaro 3.4 with 5-speed and have noticed (as others on this forum have) that my a/c compressor doesn't cycle. I searched the forum and the only relevant thread I saw didn't get me any farther than what I already know: some modern compressors never cycle, and the 3800 v6 is equipped with such a compressor.
My a/c blows pretty cold, and the high/low side pressures are within normal ranges. Watching the pressures while running the car, I didn't really notice much in the way of fluctuation.
All I want to know is whether the compressor is supposed to cycle for my car, and if so, what part of the system I need to look at to correct the problem. It's been bugging me to think it's not working the way it's meant to. Thanks in advance for any help!

[Rob Bell]

I've had several GM cars and they never seem to cycle. My current Firebird does not cycle. I think the non-cycling system is called something like "variable orifice" or something like that. A haynes or Chilton's manual will probably tell you if it should cycle or not.

If it's blowing cold air and seems to work properly, i would not worry about it.

[peeeot]

I tested the system a bit more thoroughly and this is what I found.

First off, the compressor DOES cycle, but it only does so when the interior blower fan is on the lowest speed setting. This applies for both normal a/c and max a/c. When it cycles, it runs for something like 10 seconds, then cuts off for 3-4 seconds, and continues like that. The low side pressure jumps to 35 psi when the compressor cuts off; when it cycles back on, low side pressure decreases gradually to about 25 psi, at which point the compressor turns off and the needle jumps back up to 35. High side pressure remains constant at 105 psi through all this.

When I have the fan speed at the max setting, low side pressure remains constant at 33 psi and high side remains constant at 135 psi.

Are these the normal characteristics of my system?
The only thing that troubles me is I'm used to a system cycling off for about as long as it cycles on. Also, I didn't notice the underhood fan cycling, but it only has the one, so I figured it was just keeping the engine cool. Thanks again!

[Gallstaff]

Why does it matter? If it's keeping you cool then it's working to me.

Is it dangerous to not cycle or something?

[peeeot]

Not cycling could have a few undesired effects. First off, if a compressor is supposed to cycle but doesn't, it will overpressurize the system, presumably causing leaks or damage. This is not an issue for me. When the compressor is engaged, however, it puts a noticeable load on the engine, so it has to work harder, which means worse economy. If my compressor isn't cycling the way it's supposed to, it could explain below-average fuel economy. Also, if the compressor isn't cycling as intended, it seem possible it could stay engaged even when the engine revs up higher, aka at speeds the compressor isn't supposed to spin, thus damaging it.

My cooling is adequate. I just want to make sure it stays that way at a minimum cost for as long as possible--and since my system's behavior seems unusual to me, I thought it best I check if my system is normal for these cars.

[Yaba3800]

umm...i was told my compressor was broke becuase it wasnt cycling so i bought a new(used)one for $100. ur telling me its not suposed to cycle? btw my 1996 camaro 3.8 5spd blew 100degree air

[peeeot]

According to my Hanes manual, no, it isn't supposed to cycle if it's the 3.8. I would hope a technician at the Chevy dealership would know for sure--you could try calling and asking. I have in the past, and they answered my questions even though they weren't making any money off it.

[Silver 99 Camaro]

They do not cycle on 3.8's. They are axial compressors that adjust internally without turning on and off.