Hi,
I've a '90 MR2, non turbo auto, nothing special. When I brought it (during winter), I didn't notice that the aircon didn't work. A hvac mate gave the schrader valve a push, and it was empty. The high and low pressure valves are 3/8" x 24 threaded, so we attached some gas and put 800 grams of R134a into it. Now that all worked out great, nice and cold in the summer heat.
In conversation with a more experienced tech at his work (heat pumps, not car AC), the tech mentioned that seeing as the schrader valves were 3/8" threaded, and not clip on, it was more likely that the original gas would have been R12 instead of R134a. Apparently those fittings are a reasonable indicator. Of course those two gases are compatible (they use different oil), which means I may have the wrong stuff in their. That's no biggy either, as we have some R134a, some R12 (which is illegal now iirc), and some Iceon xxx or some such, which iirc is an R12 replacement.
There is supposed to be a tag on the compressor with the gas type, but stuffed if I can see one.
Long story short, it's easy for us to either change the gas or the oil, we just need to know what it's supposed to take. Sooo, anybody know what an early SW20 MR2 takes from the factory?