Q: What are the signs of loss of oil?
Signs of loss of oil are: all rods and bearings worn or scored, crankshaft uniformly scored, rods broken from seizure, or little or no oil in crankcase.

Q: What causes loss of oil?
Loss of oil is a result of insufficient oil in the crankcase to properly lubricate the load bearing surfaces. When there is not enough refrigerant mass flow in the system to return oil to the compressor as fast at it is pumped out, there will be a uniform wearing or scoring of all load bearing surfaces.

Q: What can be done to avoid loss of oil?
(1) Check oil failure control operation if applicable.
(2) Check system refrigerant charge.
(3) Correct abnormally low load conditions or short cycling.
(4) Check for incorrect pipe sizes and/or oil traps.
(5) Check for inadequate defrosts.