What Causes Cylinder Scoring in Automotive Compressors?
3 Answers
Main reasons include lack of lubrication from refrigeration oil or internal malfunctions. More about compressors: 1. Introduction: The automotive AC compressor serves as the heart of the car's air conditioning refrigeration system, responsible for compressing and circulating refrigerant vapor. Compressors are categorized into fixed displacement and variable displacement types. Based on working principles, AC compressors can be divided into fixed displacement compressors and variable displacement compressors. 2. Classification: According to operation methods, compressors are generally classified as reciprocating and rotary types. Common reciprocating compressors include crankshaft connecting rod type and axial piston type, while typical rotary compressors include rotary vane type and scroll type.
I've seen quite a few cases of this during car repairs. There are several main reasons for compressor cylinder scoring: insufficient lubrication is the most critical, such as when the system leaks refrigerant and there's not enough compressor oil, causing direct dry friction between the piston rings and cylinder walls; impurities or moisture in the refrigeration system can lead to metal debris getting stuck on the cylinder walls and causing scratches; using low-quality compressor oil during installation can result in oil film breakdown under high temperatures. Another scenario is when water enters the AC system and isn't properly addressed, leading to moisture entering the cylinders and causing rust, which then damages the cylinder walls during piston movement. The most troublesome cases involve improper repairs or modifications by inexperienced technicians, where incomplete vacuuming introduces air into the system, creating localized high temperatures during operation that cause metal adhesion. It's recommended to check refrigerant levels and oil condition during every maintenance service.
Having driven cars for twenty years, compressor seizure is mostly a maintenance issue. The most common problem is not replacing deteriorated refrigeration oil in time, especially in high-temperature southern regions where the oil film easily fails; condenser blockage leading to poor heat dissipation causes the compressor to overwork and temperatures to skyrocket; repeated refrigerant shortages result in insufficient lubrication. I once experienced this myself: dust and impurities entered the pipeline, turning the refrigerant into an abrasive during circulation, literally scraping the cylinder walls. Using non-standard refrigerants at modification shops can also cause problems, as different refrigerants have different oil requirements. Now I’ve learned my lesson—I always clean the air conditioning system before summer, especially the receiver-drier.
