After purchasing my Volvo in February, I tried the A/C in June and it was not cold. I had the system recharged with dye after performing a nitrogen pressure test where the system held pressure. After only 1 month of infrequent use, the compressor is turning on an off. Since elsewhere in the forum I've read that this is an indication of low charge, I'm assuming that I've lost the refrigerant again. However, I would have thought that to lose the refrigerant that soon, I should have a fairly large leak that the nitrogen pressure test should have discovered. I'll bring my car back to the Volvo dealer mechanic nearest to me to check this, but I'm concerned that maybe this dealer mechanic is not reputable. When I first brought the car in to have the A/C looked at, the mechanic immediately recommended replacing the evaporator after the pressure test held pressure. Only after I said "Wrong answer" did he suggest recharging with dye. Am I being paranoid? Is it likely that a leak which was not detectable by pressure test would leak out a full charge of refrigerant in this short a time?

Thanks for any suggestions,

Matt