I recently dealt with this problem. 2003 Outback A/C compressor stops
working mostly when hot
Low pressure tested around 20 PSIG after a while, when idling at 1500
RPM. The high pressure was around 210.
Temperature in the center vents would go down to 47, cycle back on at 51.
The compressor would cycle a few times and then stop for a while.
Temperature would go up to the 60s or 70s and then, the compressor would
restart and go down to 47.
After hooking a pilot light to the compressor clutch power lead, I found
that the control was calling for cooling but the compressor would not
engage. A fast light tap on the clutch would engage the compressor.
Measured the clutch gap and found it to be around 0.090". Took the
clutch pulley out, removed 0.080" in shims to bring the gap to the
0.010" to 0.020" spec for the zexel compressor.
The a/c has been working normally since then.
I hope this info helps.