My dad recently had the a/c compressor replaced on his ailing 1992 240 wagon becuase a prior conversion had been botched, tearing up the system. Ever since, the oil guage will creep up to the "red zone" after having the a/c on for about 20 minutes. Fearing possible overheating, he's stopped using the a/c after putting in @ 1K. Unfortunately, the shop that did the repair has since gone out of business (I wonder why!)--so he can't take it back there. Any ideas what is causing this problem? I'm hoping that this is a basic repair rather than another huge $$$.