I put a new engine in my S2000 and now I need to recharge the A/C. The system was open for a little less than an hour as the new engine had a new compressor on it that I hooked up. My question is how much oil should I have them inject into the system? I'm assuming some of the oil evaporated when the system was open so I can't just have them put back in what they take out, correct? I'm going to have the system evacuated for a few hours and then recharged to 1.2-1.3 pounds.

My service manual says:
25ml for the condensor
40ml for the evaporator
10ml for the line/hose
10ml for the receiver/dryer
25ml for leakage repair
For compressor replacement subtract the volume of oil drained from the old compressor from 130ml and drain the calculated volume of oil from the new compressor: 130ml - volume removed from old compressor = volume to drain from new compressor.

I don't have my old compressor anymore so what should I tell them to inject?

Thanks for the help!

 

Late to the game I know, but the proper fix for you would require that the High and Low sides have a flush performed, replace the receiver/dryer, and refill with 130ml.

The receiver/dryer is fairly inexpensive, ~$30, which would make replacement a non issue. Just my $.02.