Tis' the season for A/C issues...

[MGPD03]

I've done quite a bit of digging, but was unable to find exactly what I was looking for.

The issue: My wife's 2000 Cavalier 2.2 is experiencing technical difficulties. Last summer/fall the A/C worked fine, but when we had an unseasonably warm day toward the end of February I cranked it up and nada but luke warm air.

I thought it'd be a simple fix i.e. $30 recharge kit...nope. It's holding a charge at just less that 65psi (I think...whatever was right on the verge of yellow on the gauge). I think the problem is that the compressor isn't kicking on.

I can hear a click from the relay but the clutch doesn't engage. The underhood fuse is fine....I'm stumped.

I've never really dinked with A/C systems and if there's a way to blow up my garage messing with it I'm sure that'll be the first thing I screw up.

With all the infinite wisdom on the boards these days, I'm sure someone has an idea and/or a starting point. If there are any viable online resources I'd be happy to check those out as well if you point me in that direction.

Thanks in advance.

 

[mechtech2]

When the system has NOT been run recently, and has stabilized, the high and low side have the same reading.
Is this the 65 you measured? It should be around 90. 65 should be enough to trip the pressure sensor, though - there is a minimum pressure needed before the system will work.
Who knows - there are so many parts. Try hot wiring the compressor with the engine running, and see what the low side reads. This will tell you if the clutch/compressor is working, and if you have enough juice.

 

[Colt45ws]

I agree. My car has 95psi off. You need a real gauge to find out what it really is.
Check the wiring at the compressor for voltage with the A/C on or maybe bypass the relay and check it with the engine off since it is so close to the belt.
You can PM me for specific procedures and information..I have Alldata for my '98 Cavalier which would be very similar to your wifes car.

 

[ThirdeYe]

Just something to think about, the service manual in my car recommends that you run the A/C for about 10 minutes once a week in winter to keep the A/C working well for the summer time. Don't know if that's the same for your vehicle, though. I haven't had a cavalier in years and I didn't care about car maintenance back then.

 

[WalterMitty]

My Chevy pickup was hinting it was a little low last fall. After spending the winter mostly in the garage (because my #2 car gets twice the gas mileage) it didn't want to cool.

The clutch on the AC compressor was engaging (the click noise) but it would only make a couple of revolutions and then kick back out even when set to MAX AC. So I concluded it had gotten so low it was kicking out due to low pressure.

Almost as soon as I started feeding the new can of 134a to it the compressor started running and cooling. It took almost 3 cans of 134a to get the system charged back up.

Have you tried adding anything to the system?

 

[kgb007stb]

65 is low, considering that the ambient temperature was around 70-75. A can of 134 can easily produce 100-120 psi of pressure depending on the ambient temperature. My system produces roughly anywhere from 90-120 psi when at rest, I have experimented with this pressure so much that I am able by just measuring it tell if a car needs to be re-filled. Since you did not run your AC over the winter as many have suggested, all of the gaskets did not get re-lubricated with oil, shrank or cracked and some 134 seeped out of the system. You can try to connect the can to the 134 low side with a gauge and see is the can will be able to pressurize the system before it fires up. Make sure that your hose has a back pressure valve otherwise if the AC decides to spit something back into the can, it will explode in your face. Once it fires up, the low side is anywhere from 25-35, I like to charge my systems around the 30-35 mark, a little on the higher side but my car has a cut off for over pressure so I am not worried at all. Good luck

 

[Sparkman]

Most vehicles run the compressor on defrost to dehumidify the air.

I would start by testing to see if the clutch is getting voltage.

 

[MGPD03]

UPDATE: My dispatcher's fiance was a mechanic and has all the necessary testing equipment (and know-how) to diagnose the issue...if anyone's interested, I'll update the thread when it's resolved.

 

[mechtech2]

I'll resolve it right now - add some sauce!