Got to say that the a/c in mine works really well. Only newbie advice I would offer is to note that to check the oil you do it immediately after switching the car off and be prepared to have the prancing horse logo scalded into your palm as you remove the oil cap.
Sounds like a leak in the condenser. Check for stones embedded into it like mine had ... then when you get it fixed ... get a piece of wire mesh put behind the air scoop if it hasn't one already!
Ahs anyone managed to figure out how to stop the bypass valve rattling, other than either a new one or wiring it open? Would putting wire in to give it just enough tension to be fractionally open at idle solve the issue?
I think once they are gone, they are scrap. Wiring it open works ok on 2.7 motronic, but it does upset 5.2 cars, and i think they dont sound as good personally. I'd replace it. Thing is, these cars arent new anymore, and things need replacing. All part of running a 355.