Most common causes of AC compressor failure

Compressor failure cause #1 — lack of lubrication due to low refrigerant charge

Auto AC systems rely on the refrigerant to carry refrigerant oil through the system to lubricate the compressor piston/scroll seals. When an AC system develops a leak and loses refrigerant, it also loses oil at the same time. From that point on, the system is low on oil. If you run your AC system when it’s low on refrigerant, you’re also running the compressor when it’s low on oil

That causes accelerated compressor wear that results in fine metallic particles accumulating throughout the system. Those particles can collect in the orifice tube filter or in the expansion valve.

Compressor failure cause #2 — air and moisture in the system that degrades the oil

When you have a leak, refrigerant not only leaks out, but outside air can enter the system, along with any moisture in the air. The air and moisture causes the refrigerant oil to oxidize, break down and form acids that attack the metals in the system. The degraded oil also lacks its full lubrication ability, so you get accelerated compressor wear. That compressor wear and acid formation develops into a slimy black coating throughout the AC system that’s referred to as “black death.”

Once the system is opened for repair, the slimy black film is everywhere in the system. Fixing a system that’s contaminated with black death requires the replacement of the compressor, condenser, receiver/dryer and a complete flush of all AC lines and evaporator.

Compressor failure #3 — refrigerant overcharge

When the system is overcharged, the compressor has to work harder to compress the refrigerant. That wears out the compressor seals much faster and stresses the compressor crankshaft and swash plate.

Contamination causes compressor failure

Moisture, air, incorrect oil, incorrect refrigerant can all cause premature compressor failure.

Posted on July 27, 2023 by Rick Muscoplat