Get a few questions about how to know if you have to much or not enough oil in the A/C system.
The A-6 drain plug should be named the oil level plug. The manual trans and the differential have a upper plug that you can fill and check the oil level, usually 1/2" below when cold. The A-6 drain plug is above the bottom of the compressor oil pan. It is there to bleed out excess oil in the system. You could probably use it to see if there is not enough oil also. I would pass on that.
The A-6 drain plug has a hole drilled thru the center that joins 2 holes just under the head of the plug. It was designed to drain excess oil and only loose a fraction of the system pressure. It will make a mess when done correctly as any excess oil will squirt out first. The gas will hiss when the oil is correct. You only slightly loosen the plug to do this. This procedure is in the manual and tells you how long to run the system to drain the excess oil and to re drain if necessary.
Pumping oil will get things hot like a hydraulic pump. The auto trans cools it's oil going thru a tube in the hot radiator. To much oil can heat the system up and also the engine because the A/C condenser is in front of the radiator. The later A-6 compressors had a thermal switch on the back plate of the compressor. It got it's temp from the high side pressure inside the compressor and would send a signal to release the compressor clutch if the system was overheating.
The A-6 has a oil pump, oil pick up tube, and oil pan that should have over 4 oz of oil in it. The oil lubricates 2 case bearings, 2 thrust bearings, front seal, and piston rings.
Thought this might help now that things are warming up.
DOM
The A-6 drain plug should be named the oil level plug. The manual trans and the differential have a upper plug that you can fill and check the oil level, usually 1/2" below when cold. The A-6 drain plug is above the bottom of the compressor oil pan. It is there to bleed out excess oil in the system. You could probably use it to see if there is not enough oil also. I would pass on that.
The A-6 drain plug has a hole drilled thru the center that joins 2 holes just under the head of the plug. It was designed to drain excess oil and only loose a fraction of the system pressure. It will make a mess when done correctly as any excess oil will squirt out first. The gas will hiss when the oil is correct. You only slightly loosen the plug to do this. This procedure is in the manual and tells you how long to run the system to drain the excess oil and to re drain if necessary.
Pumping oil will get things hot like a hydraulic pump. The auto trans cools it's oil going thru a tube in the hot radiator. To much oil can heat the system up and also the engine because the A/C condenser is in front of the radiator. The later A-6 compressors had a thermal switch on the back plate of the compressor. It got it's temp from the high side pressure inside the compressor and would send a signal to release the compressor clutch if the system was overheating.
The A-6 has a oil pump, oil pick up tube, and oil pan that should have over 4 oz of oil in it. The oil lubricates 2 case bearings, 2 thrust bearings, front seal, and piston rings.
Thought this might help now that things are warming up.
DOM
......The one in my photos wasn't from a Corvette. This one was deep inside the Vee of a Jaguar V12. You can see the effects of the seal issue. However, the seal design "expects" a small amount of oil to be extracted from the unit to keep the ceramic seal lubricated. In the cavity of the A6 housing, a cylindrically shaped felt seal(pic above in the background with the clutch/pulley pic) keeps it in check. When the seal gets saturated, like the one above, too much oil escapes and makes a mess. Particularly not good for a fiberglass hood!
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