Oil...The Lifeblood of the A/C System
Oil is an important part of the A/C system. Refrigerant charged oil circulates through the system while keeping 60-70% of the oil in the compressor at all times. This provides adequate lubrication to reduce friction (heat) and wear (metal particles that will cause premature compressor failure and clog condenser passages). When doing a compressor job, it is always advisable when removing the old compressor to drain the oil to see what sort of condition the system is in, and to see how much oil is inside the compressor. This will also help to determine if there is any oil left in the system or if the compressor failure was due to low refrigerant oil.
It is also advisable when installing a new compressor to check the amount of oil inside it, to ensure the system gets the correct lubrication.
Compressor oil should look clean. Always check for
contaminants that are in the oil.
Compressor oil that looks like this is an indication that the compressor became hot and the system is contaminated.
Compressor oil with dye should look clean with a green color. Always check for contaminants that are in the oil.
Always check the oil on failed compressor and new compressor. Undo the plug to remove the oil.