All systems will lose charge over time. As mentioned the 134 leaks faster than R12 in the same system. To get around this, 134 systems used barrier hoses that reduce the leakage rate through the hoses.


Oil will leak a lot slower unless you have a real leak (broken line bad seal).

A good test would be to check to see if the low-pressure switch is open or not. If its open opens when the AC is on then adding a can of refrigerant is a low risk test.

My understanding is if the low-pressure switch opens both the clutch and the AC fan will be off, they are on the same circuit.

I would get a meter out and test the low-pressure switch.

Kevin