How to Check the Oil in an Air Conditioning Compressor

by Joshua Kinser
itstillruns article image
interior of the car image by Astroid from

An AC compressor is the device that circulates air and coolant to cool air as it moves through the AC system of your vehicle. The AC compressor requires oil to lubricate the unit and to keep the piston and other moving parts from seizing. Checking the oil is not the easiest procedure to do for an amateur mechanic as it requires the AC unit to be hooked up to a recovery machine, to ensure that Freon is not released into the atmosphere. Unfortunately, there is no dipstick to check the amount of oil in a compressor and the oil must be drained and replaced to ensure there is a correct amount of oil in the AC compressor unit.

Step 1

Secure the reclaimer machine to the two valves on the AC compressor labeled high side and low side.

Step 2

Turn on the reclaimer machine.

Step 3

Locate the high and low side valves on the reclaimer machine and open them up to the "on" position.

Step 4

Depress the button on the reclaimer machine labeled "reclaim". The machine should run fully until the gauges that are labeled for the high and low valves are reading "0." This means that the Freon has been pulled from the compressor.

Step 5

Turn off the high and low valves on the reclaimer machine. The gauges should still read "0" on the reclaimer machine.

Step 6

Remove the reclaimer machine lines from the AC compressor.

Step 7

Remove the compressor from the vehicle. Open drain valve on compressor and drain oil into a measuring device that can measure liquid ounces. Compare the liquid ounces of oil drained with the amount of oil required by your vehicle's AC compressor unit. If the amount is less than drained you may have a leak and you AC compressor should be pressure tested for leaks.

Step 8

Fill compressor with recommended oil amount and replace drain cap. It is important that the oil amount in the compressor is exactly the recommended amount. Too little or too much oil is harmful to the AC compressor.

Step 9

Replace compressor in vehicle.

Step 10

Hook the reclaimer machine to the compressor and recharge Freon into the compressor by hitting the "charge" button on the reclaimer machine. You AC compressor oil is now checked and the Freon in the AC compressor has been recharged.

More Articles

article divider