Faulty AC Clutch/Compressor?

The system senses coolant pressure.

If the pressure is outside of limits, the pump will not run. I have seen low pressure (leak) cause the pump to cycle.

Don,

If it keeps working OK, great! If not, here's some things that I had to check when my A/C started going buggy:

1. Pressure switch in Freon line (as noted in previous post)

2. Possible bad wiring or connection

3. Flaky compressor relay or connection

4. Low on Freon (not too likely, but an A/C shop can check it pretty easily)

5. Bad dashboard switch or connection

I'm sure there are other things, but this was as far as I got before deciding that it was the compressor, which turned out to be bad. Because of the safety aspects (high pressure gases, recovery of the old Freon, etc.) , I ended up buying a rebuilt compressor and taking it to a good shop for the actual work.

Good luck & stay safe!

Logan

I would assume you were a victum of refrigerant migration
It can destroy compressors as in broken rods, pistons and reed valves
All refrigerants can migrate to the coldest part of the system
If the compressor is the coldest part (while parked and not in use)
when you start the compressor it may be full of refrigerant in a liquid state
which disolves into the crankcase oil then the refrigerant boils out of the oil
making it foam like crazy and then the compressor has to pump this large
amount of oil and liquid refrigerant mixture
and as the pistons and rods go bang bang bang the compressor may pump
this un compressable mixture that then goes to the screen on the expansion device
and slows down the flow and the low pressure switch cycles the clutch off
After a short time the oil finally squeezes through the screen and everything
may be back to normal if the compressor hasn't broken a rod or reed valves
Since car a/c's don't have a crankcase heater to prevent this damage I try not
to turn on the compressor until I know the compressor has warmed up
from the engine heat
That's my theory

In addition to the good suggestions that were posted Logan, I have had a few high mileage compressors that had worn the gap between the compressor clutch and face plate. The additional air gap required the clutch coil to be at it's best to generate sufficient pull in power. If this only happens after first starting the truck, The voltage getting to the coil may be low until the voltage stabilizes. If you want to test this, put a volt meter across the coil leads when the clutch is not working at a time when it should be. (That is if you can force the problem to repeat.) If there is voltage at that time, use the back end of a screwdriver to tap the non spinning center of the compressor. If it starts to spin, and stays spinning, you have a few choices.

1) Wait till the voltage builds and retry.

2) Close the air gap on the clutch.

3) Replace the coil and clutch on the compressor.

I had the problem on a limousine, and had to resort to a relay to bring better voltage to the coil. This was on a Ford, if it matters. Good luck.