dromel

The a/c on my 1998 Maxima GLE works fine once I get it started. When initially starting it in AUTO mode, the fan comes on but it blows warm until I turn it off, and on once or twice and than it works fine the rest of the day.
Last year the a/c man at my mechanic's shop told me it was caused by a sticky pressure relief valve; part cost $56 from Delco. He wasn't sure if the system need to be drained before replacing it.
Last week when I went back, the shop's owner said "no, you need a whole new system, about $950. Soooo...
1) Does a sticky pressure valve sound like the correct diagnosis?
2) If so, is this something I can replace myself, or must the system be drained, purged and refilled at an a/c shop?
Thanks
By the way, have 135,000 miles and the only "repairs" done were a new starter and radiator. Great car!

ATTappman

He must've been talking about the thermostatic expansion valve, mounted inside the evaporator box. It sounds like a plausible explanation, but he's probably just guessing. The part is only about $30 from a parts store. To change the expansion valve, the refrigerant does have to be recovered, the part changed, and the system evacuated and recharged.

There is a relief valve on the compressor I think, but it doesn't relieve unless the system pressure gets to some crazy high value like 500 psi. If it stuck open, the whole system would discharge in about 2 minutes.