Oil pressure lower than normal or no oil pressure

Low oil charge - Verify oil level requirements

Faulty oil pump drive segment - Verify oil level requirements

Refrigerant flood back

Do not allow more than 1/3 of system on defrost at any time. Verify proper operation of defrost system. Increase super heat or replace expansion valve. Correct problem or replace evaporator fan.

Desuperheating expansion valve stuck open. - Replace expansion valve

Desuperheating expansion valve stuck open. - Replace oil pump or oil pump assembly.

Worn compressor bearing - Replace compressor bearings