08/18/2026
AC System basics.
If you replace a compressor, condenser or evaporator core you should measure and add the correct amount and type of AC oil directly into each part before installation.
Most vehicles list a full oil capacity as well as a chart of how much of that capacity should remain captive inside each device.
Getting the oil level set correctly is very important to a solid working AC system.
Once you set the oil and Freon levels that should remain without service unless a leak develops.
If you have to add Freon there’s a leak that needs to be resolved. Then the Freon should be evacuated, weighed and added back to within a fraction of an oz for proper operation.
Judging how much AC oil leaked out of the system can be tricky. The only true way to 100% know is to remove and drain each part of the system and add back the correct amount of oil. Although you can also drain and measure the oil from the part you’re replacing and add that same amount back. That’s assuming that a large amount of oil didn’t leak out of the system.
