I'm checking out the a/c in a newly-acquired Volvo 240 wagon. It's a '93 model and has the improved 9/740 style accumulator system.

I'm fairly familiar with the older drier systems used in these cars having completely replaced the system in my '83 model, but not so familiar with this one.

When I got the car, it had not been driven for a couple of years and while there was about 40 psi in the system when the engine wasn't running (low side) , the a/c wasn't engaging and when I hot-wired the compressor to check things, the low side went to 0. I put one can of DuPont R-134a in the system and now have these numbers.

Here's is what I'm getting:

Ambient: 89
Vent Temp: 41
Low Side: 21 while the compressor is cycling. When it switches off, it climbs to 41 and then it kicks back on. It will run for about 45 seconds or so and then cut off and turn back on fairly quickly as the pressure rises.

I can't check the high side as there isn't a port provided.

Of course, the PROPER way to charge one is with a machine, pulling vacuum and then puttin the recommended charge back in, but I don't have that option.

Thanks!