First off, if the right side windows are both down about 2 to 4 inches, you get an inside wind at 35mph or more that will do a fine job of moving a lot of air around the cabin. System works best with the blower fan on #2 max, the left side windows closed, and only you in the car. Too noisy for a passenger. Very helpful if the car has power widows. I survived several Houston summers that way in a 1983 245GL.

If a conversion to R134 refrigerant has been done, there should be (1) a different-looking fitting on the low side service port on the back of the compressor, and (2) a label stating that the conversion was done.

It is not easy to see the back of the compressor, it's down there below the AMM. There are two fittings, the one nearest the fender is the low side. Might be easier to see if you use a flashlight after dark.

If the conversion has not been done, there are several options. One, of course, is to do the conversion. Folks here are of mixed opinions on whether to go with the Volvo kit, which contains many new parts and runs around $200; or to do the cheaper method of just changing a few parts and the compressor oil.

There is the third option of re-charging with R-12 which is expensive, and in a potentially leaky system, not the best plan. If you are near the Mexican border, you might check for lower cost R-12 over there.

Another option is the use of an R-12 alternate refrigerant. It carries this caveat - once used, no a/c shop will touch your car system. They have legal recovery equipment for R-12 and R134 only. Your's would be a "contaminated" system which would contaminate their expensive equipment. That said, one of the alternatives is Freeze 12. I found a source in Austin, it was $9.00 a can. I had to buy a side-tap for opening the can, but then my R-12 gauges worked fine.

One of the BB gurus here, rhaire, has run Freeze-12 several years in several Volvos (in Florida) and is pleased with it.

Good Luck,

Bob

:>)