What are the symptoms of oil shortage in an automotive air conditioning compressor?

[IsabelLee]

What phenomena occur when an air conditioning compressor lacks oil: Low efficiency: Reduced efficiency, resulting in very poor cooling (or heating). The compressor frequently goes into protection mode (increased wear due to oil shortage leads to lower compressor temperature). Seizure: The compressor often seizes, especially when there is a significant temperature difference between indoor and outdoor environments. The air conditioning compressor functions to compress and drive the refrigerant in the air conditioning refrigeration cycle. It is typically installed in the outdoor unit. The compressor draws refrigerant from the low-pressure area, compresses it, and delivers it to the high-pressure area for cooling and condensation. Heat is dissipated into the air through the radiator, and the refrigerant changes from a gaseous to a liquid state, with increased pressure.