Re: 300sd diesel A/C compressor

Someone gave you bad information. The system has no sump, the refrigerant oil circulates with the refrigerant and so flows throughout the system.

The initial oil fill for a R-4 Frigidaire compressor is 5.75 fl oz LESS what's already in the system - in the evaporator, in the lines, condenser etc. Your guess as to that residual quantity is as good as mine.

Once you open the system the receiver-dryer should be replaced.

I bought an oil cartridge for R-12 systems that I attached to the suction fill connection. The cartridge has a screw that one turns to force the oil into the running system. The oil quantity is known so one doesn't over do it and create a hydraulic lock inside the compressor. Each of these oil cartridges cost about $10 and avoided opening my old car's R-12 system.

Not to sound rude but in the best interest for you and your vehicle, I would tie up the lines, clean up the mess and take the car to someone who knows what they're doing. You clearly do not and can damage a $500 compressor in no time.