Last year the Air-con on my Skoda Octavia(2002 1U) started behaving erratically. Did some basic diagnosis(pressure check in both lines, fans and compressor clutch check) revealed something wrong either with :-
1. Thermal expansion valve(TXV)
2. Refrigerant control valve(RCV)
After some further diagnosis, I confirmed it was the RCV. I proceeded to take the car apart. Upon examining the compressor internals, my suspicions were confirmed, it was the RCV. But the compressor had some aluminum shavings in the oil. This was very bad news for my walletKeep on Reading!