The a/c in my '84 Westy, probably the same as the '85,  was fitted at the
port of entry I believe.    It disturbs me that there is no low freon
pressure switch.
Mine leaks very slowly,  I have to add a can of R12 every year but I have not
been able to pin point a leak with my detector.         I think it is highly
likely that it has been run with insufficient freon in its past.     The
system was empty when I bought the van 3 years ago.
However the point is,  the compressor whines also.
It whines particularly loudly on low settings.
Before I modified the ductings it didnt work well enough for me to use the
lower settings and the 747 noise level on high would have masked the sound
anyway.
Fortunately it does cool the vehicle, albeit a bit slowly , here in SC

I think the whining is a cavitation although the inlet pressure on the low
side is about 30 psi.
I had a Fiat once that had a whining compressor for years so it might not be
too detrimental.

How many other people have whining compressors, and is there an expert on the
list that can tell us what the pressures should be with a properly
functioning system?

Is the compressor destroying itself rapidly?

Would pumping the system down with a vacuum pump and recharging it get rid of
the whine?

Thanks,
Steve Cotsford
'84 Westy