Air Conditioning Problems

[brutus90]

My 1998 Cavalier with 2.2L is having issues with cooling. I recharged the system quite some time ago (about 3 years ago I think), and it was cooling pretty good up until this year.

When hitting the AC button, I would hear a sudden vibration that would go away when shutting off the AC button. After a couple times switching it on and off, then leaving it on, it would cool well. Then it got to the point where it would make that vibration sound everytime.

After I wasn't comfortable turning on the AC, I checked the pressure (only have a single gauge for the low side). It was reading about 100lbs. I relieved the pressure and brought it back down to 45lbs, and, while the compressor doesn't make that noise anymore, there is no more cold air. I can see the pressure go up when the compressor is off, and then go back down when it kicks on, so I'm guessing the compressor is still working, but I don't know what to do next.

Does anyone think my gauge is inaccurate? If not, what else could it be?

[J-Ri]

Don't release refrigerant into the atmosphere! Not only is it illegal, but it destroys the ozone layer... in my opinion that's probably the reason behind the law In this case it doesn't make sense anyway... obviously your system didn't gain refrigerant since you filled it.

100 PSI is where it should be with the A/C off with the temperature somewhere around 80-90F. If it's that high with the A/C on, you need a new compressor. Sounds like your clutch may be bad and slipping/chattering. If it is, the compressor won't be able to compress the high side as much as needed. When the clutch slips and wears out, it produces lots of heat which damages the shaft seal on the compressor which will make it leak.

If the clutch is worn out, it may be because the system was overcharged when you added cans to it last time. The V5 compressor in your car doesn't cycle on and off to maintain the low side pressure, there is a plate inside that varies the stroke to hold the low side pressure where it should be. I have never seen one of these clutches wear out because they rarely engage, just once when you hit the A/C button. If the system was overcharged, the high side may have got too high and the compressor was cycling because of that. Even if it wasn't cycling, the extra force on it could have been making it slip just a little bit and over time it wore out. Another reason the A/C system should always be professionally serviced.