How to Add Oil to an Auto's A/C System

The air conditioning system needs oil to operate properly, but the compressor is the only component that requires internal oiling. Whenever you replace a compressor, you must fill the new one with oil, unless the manufacturer states that the compressor is pre-oiled. If you flush the air conditioning system, you must add new oil to the system. Always replace the drier or accumulator when you change the compressor or when you flush the system.

Instructions

1

Open the oil plug on the compressor using the appropriate socket. If your brand compressor does not have an oil plug, the oil is filled through the lines in the back of the compressor, where the manifold is attached.

2

Pour the appropriate amount of oil into the compressor. Each type of compressor comes with instructions to tell you how much oil it takes. If you have the type of compressor for which you must put the oil in through the lines at the back, the instructions will tell you whether you need to fill it at the low side, high side or both. If you put the oil in through the lines at the back, you may have to top the compressor a certain way. This is always outlined in the instructions.

3

Reinstall the oil plug or cover the holes for the lines at the back of the compressor with a clean rag. Set the compressor up on the clutch for 20 minutes to allow the oil to run to the front of the compressor to soak the seal. If you do not allow the seal to soak, it will leak.

4

Install the compressor according to the process for your particular vehicle. Ensure that the manifold area is clean of all debris before you attach the manifold and lines.