Turns out the used '95 Grand Prix I bought a few weeks ago is slowly losing refrigerant. So I bought a can of refrigerant with leak sealant and put it in. Pressure was a little lower than my shop manual said it should be, but it was blowing cold so I didn't add a second can.1st question: should I have put more in?
Second question: a black cap was on the high pressure side, and a red one on the low pressure side. And I experimentally determined those caps are interchangeable, which I found surprising. I retrofitted my old truck from R12 to R-134A, and the new caps were definitely different and not interchangeable. So I'm wondering about this. Seems the red cap should shout DANGER and be on the high side. Any comments?