Hi... my 96 has been acting like it needs a freon recharge. (on/off cold while driving, clutch clicking on/off when idling, generally lousy cold air from the vents when it works, a/c works less as the car heats up) This has been happening for a few days now... the compressor, when on, sounds fairly loud. It's a continuous noise that you can hear over the engine at idle. Car is fairly new to me (couple months) and the A/C, while not amazing, has been working.

So I went out to the store to buy a 134 charge kit and I stuck a thermometer in my vent. Best I could do on a cold engine at about 95 degrees ambient was around 67 degrees. Bought my stuff, went on a couple more errands and that's when it really started to act up after about 10 minutes. In stop and go traffic the clutch was cycling on and off every 5 seconds, I just turned it off to save wear on the compressor.

Got home, read the directions, saw that the can suggests 50-55 psi on the low port in hot weather. Attached to the port and saw 64 psi so I stopped there. At this point the vents were putting out about 80 degrees so I know the compressor was on.

I'm reading a little more online and some suggest holding the revs at 1500 - should I be doing this? Will that drive the low port PSI up or bring it down more?

Should I bleed out some pressure to get back to 55 psi?

The can says to run the car for 3 minutes, does it matter if the car has been running (in my case, 45 minutes and heat soaked) or should I do this when everything is cooled off?

 

Sounds like it has enough freon. Check this, item 2 in the 850 sticky: https://volvoforums.com/forum/volvo-850-16/hot-topics-helpful-information-how-diy-repairs-26114/

 

I don't think the clutch needs to be shimmed... It seems as though the freon is artificially high from the hot engine. I'm going to try and run the car for 3 minutes from cold andnsee what the reading is.

Btw, there is no high pressure port on these cars, right? Just low?