I'm a novice when it comes to A/C systems....

so my 92 740 wagon sat for a couple months, I had to recharge the battery, and found it was a nearly dead battery (ok, 6 year old walmart special the PO had installed just before I bought it). new battery, vroom, all is happy.

but, the AC isn't chilling (was working great when I last used it), and I'm about to sell this car to my son's GF who lives in Nevada, where its hotter than Hades all summer.... this car has a Volvo OE R134a conversion kit, and has always worked quite well, although it needed a charge last summer

I figured I'd get my meter out this AM and run down the chain of control, but realized when I started the car and turned on the A/C, the compressor engages for about a second, then disengages. 5-10 seconds later, repeat.

now, when I last had it charged, they put dye in it, my UV light sees not a hint of glow around any of the a/c fittings, nor around the drain holes underneath the car.

is it likely its just low on freon?

 

The compressor cycling like that indicates low on freon. See if you can borrow a set of AC gauges and get a can of 134A. My bet is you'll only need maybe a 1/2 can to top off the system. The gauge pressure will tell the story. The low pressure gauge should read between 35 and 45 psi with the car idling at 1500 rpm. Assume 70-80* outside temp.

 

Low on freon +1

 

super interested in this, because it is the same thing on my wife 1992 240
checked and the pressure looks good
jumped the pressure sensor and the same thing happens. It gets cool but it does not do the same things as my 1991 240

 

was low on freon. A/C shop found zero evidence of leakage, not a trace of the UV dye on anything external, so they evacuated and recharged it.. I *know* the AC was working great last fall, I drove 7 hours in 110F weather with it chillin just fine.

fresh charge, and good as new.