Thanks. I'll check that port -- presume you mean the gizmo on the oil pan side
of the compressor. On my car its in a difficult place to get to. Another
possibility -- some compressors have a place to put oil in when the system is
not under pressure.
If its working ok, don't "fix" it. Short cycling can, I think, be due to many
things. I've heard that systems with too much freon can short cycle (if there
is a high pressure switch to stop the compressor at rated pressure). As far
as feeling the compressor cut in and out, yes thats true on mine too. Bentley
shows that some models have switches to cut off the compressor at full throttle
and in first gear!
Sounds like we've got mongrels -- GM controls, nippondenso compressors, who
knows what else! :-)