Mechanic had deemed the compressor as ‘bad’, so he bought an Ebay replacement for ~$150 (~6 oz of PAG-40 oil included), two cans of R134a, rented the vaccum pump and OEM gauge set from AutoZone, and is attempting the repair himself. He vacuumed the system for some amount of time (not sure how long) to remove moisture, then again pulled vacuum down to ~30 in Hg and it held for an hour or so. After that, he started charging the refrigerant. At 81 degrees ambient, the R134a chart says 40-55 psi on the low side, and 175-210 on the high side. System capacity is allegedly 1 pound, which would be a can and a half - and that’s what he’s charged to this point, but both gauge pressures are still not in range (40 on the low, 151-153 on the high), and the vent temp only gets down to 71 degrees. Should he charge, say, a half can more and see if that gets him there - even though he’s charged at least 1.5 cans so far, or is there something else he should be looking at?
BTW: he did not replace the filter/drier or condenser. He also said, on initial startup, the new compressor made a “terrible noise”, but stopped (maybe that’s typical of a new compressor on initial startup?).
Well, he added a little more refrigerant and noticed the compressor starting to cycle on and off. Is that pressure switch a High/Low switch (I always thought it was just a low switch)? Also noticed he had the outside air vent open. Closing that has allowed the vent temp to drop down to as low as 58, but that’s about it. Gauges are a little odd maybe … ambient is now up to 84, but now he’s below on the low side and above on the high side (39 and 300-ish). Is that high number on the high side an indication that he’s overcharged it? At 85 ambient, his high side should be 225-250 psi. If over-filled, can he just bleed some out?