AC blows cold, but compressor never stops!
I have a 1986 300e that has some issues. Last year I changed the system over to 134a and it worked flawlessly for the whole season. That winter I drove to FL (from NJ) and while there noticed it wasnt working. This spring I checked the system and found it to be low, not empty, so I evac'd the remaining charge and put a vaccum to it, which held fine for well over an hour. I charged the system and now it will not cycle off, the compress functions well though and the cars interior is cooled rapidly. Besides not cycling the compressor is a little noisy at highway speed (3300 rpm) after about ten minutes or so (a high pitched whine). I emptied the system and replaced the low side switch with no results. I am concerned that if I continue to use the AC it will harm the compressor so I have discontinued use. I have tested the belt slip and temp cutoff relay (labeled KILMA) and both cut out functions are fine. The compressor does not run when the pushbutton selesctor is on economy (which is normal ) so I assume it isnt the climate control "brain" Does anyone have nay suggestions?
1974 BMW 2002 (Heavy use show car)
1986 Mercedes 300e (Driver)
1994 Mustang Cobra (Domestic Junk)