Ensure that you clean out any remaining metal particles. Metallic debris in the system that makes it back to the compressor will quickly ruin it.

I wonder where the metal particles came from, though. Usually, that means something inside the compressor is disintegrating, as mentioned earlier.

Offhand, I don't know what the specs are for your car. But if the rebuilt compressor was empty of oil when you received it, did you add the correct amount and type of oil?

So, yes, I think yours holds 40 ounces (or whatever the under-hood sticker says).

If your vehicle is the EXT model and has the 6.2L V8 with rear A/C, my source references say that the system capacity is 48 ounces (3 pounds) of R-134a and 11.0 ounces of PAG-46 oil. But as mentioned previously, the under-hood sticker takes precedence over any reference charts. The non-EXT model wit...

It might be just a low charge. A small amount of refrigerant typically leaks from the compressor shaft seal over time. Since your wife's vehicle is now six to seven years old, enough refrigerant might have leaked out by now to begin affecting performance. Before taking the dash apart (a difficult, t...

If your original hard-to-find Shrader valves are still in good condition, I would coat them with a little Nylog Blue, reinstall them, and just replace the dust caps, which do the actual sealing.

I advise staying far away from the highly flammable refrigerants you mention: R-152a, propane, and isobutane. They're very dangerous to work with, present a fire hazard should the system leak, and they're just not worth the risk, in my opinion. As already suggested, R-12 would be best because your s...

With the HP in the 260's at around 31C (88F) ambient, I don't think it's the compressor. Chances are that the high side would be much lower if the compressor was getting weak.

For a 27C (81F) ambient, the pressures look pretty good to me. Bear in mind that the pressures will vary depending on engine and vehicle speed and hence airflow through the condenser, compressor efficiency, ambient temperature, and so on. Your 1997 Sentra has a thermistor to prevent the evaporator f...