Volvo RWD 700 Forum

OK, I read that loud and clear.
I found something called Autofreeze, AKA R-406a I think. Seems like it's pretty good from a bunch of forums I've read through.
I think it's just a low pressure situation - I have the following symptoms:
compressor cycles on and I assume off(I'll check), so does aux fan when hot.
When I change the engine rpm drastically (downshift and back up) the temp at the vents drops drastically. The AC Dryer (big silver can) is no longer frosting up, and is actually not much cooler than 80F. It's a lot cooler than the engine bay though. (I think it still frosted up last year, but I know it did the year before that.)

It's been 110 the last couple days, but the vent temps are only about 60F after running the engine hard for a while.

Does the engine have a high-rpm compressor cutoff? I think I'm either low on refrigerant or have some kind of compressor stays on too long situation.

Thanks for all the responses. I see now that R134a and Freeze-12 (which is 80% R-134a) are not miscible in the original mineral oil. (and freeze-12 sucks AFAIK).

And yes, I know of the partial pressure law - which says that teh total pressure is the sum of each pressure of each gas added up. so if I only have 25% of my original gas, I have only 25% of the pressure. Adding volume equal to 75% of the original gas would give me the 100% pressure the system should have.

Thanks everyone,
Will
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1990 740 Turbo, on its way to stock specs, maybe beyond