I recently installed brand new compressor, tx valve, condensor, evaporator, receiver drier, heater tap, everything bar the hoses basically.
A/C guy gassed it with R134A as per original. Checked for leaks. None. All pressures both high and low side spot on. Still nowhere near as good as it was when I first had the car. It used to be so cold that after a few minutes on high, even on days of 40+ I had to turn it down because it literally became painful on your skin. Now I can drive with it flat out constantly and it's barely cool. I've had three separate a/c guys achieve exactly the same result with two different compressors and I have no idea why it's so bloody average. I have thrown so much money at it the thought makes me ill, all to no avail so please post if you work out your issue 'cos I'm stumped. The coldest I've gotten it is 7.2 degrees but that was only briefly. Even at constant highway speed the temperature goes up and down like a yo-yo between low 7's and high 9's. Comparatively, based purely on feel I'd say it was blowing at 2 or 3 before the original compressor sprung a leak (I never tested it then 'cos it was brilliant). I replaced that with a genuine unit which lasted 3 months beyond warranty and now have an aftermarket which the last a/c guy said he had not seen any issues with. I'm over it.