How to Determine if a Compressor is Good or Bad?
3 Answers
To determine the condition of an air conditioning compressor, first learn to identify the three terminals on the compressor: S, R, and C. Here, S is the start winding, R is the run winding, and C is the common terminal. Then, use a multimeter to measure the resistance values. The sum of the resistances between SC and RC should equal the resistance between RS, which indicates normal operation. Relevant information about compressors is as follows: 1. A compressor is a driven fluid machine that converts low-pressure gas into high-pressure gas and serves as the heart of a refrigeration system. It draws in low-temperature, low-pressure refrigerant gas through the suction pipe, compresses it via piston movement driven by an electric motor, and then discharges high-temperature, high-pressure refrigerant gas through the discharge pipe, providing power for the refrigeration cycle. 2. Compressors can be classified by principle into positive displacement compressors and dynamic compressors. Positive displacement compressors are further divided into reciprocating compressors and rotary compressors, while dynamic compressors include axial compressors, centrifugal compressors, and mixed-flow compressors.
I've been driving for fifteen years, and last time when the air conditioning suddenly stopped cooling, I wondered if the compressor was acting up. During the inspection, I first started the engine, turned the AC to the highest cooling setting, and listened for any sounds near the compressor. Normally, it should produce a slight humming noise without any strange or clicking sounds. If there's any unusual noise, it might indicate internal wear or seizing. Then, I reached out to feel the compressor's pipe connections—if they're warm, it means it's working, but if there's no cold air, it could be due to refrigerant leakage or low compressor efficiency. I also observed the engine load changes at idle—when the compressor kicks in, there should be a slight vibration, but excessive movement is abnormal. If unsure, I'd directly use professional equipment to measure the pressure values—if the high and low pressure differences are too large or too small, it indicates a problem. To be safe, taking it to a repair shop for a thorough check is more reassuring, as a faulty compressor affects the entire AC system, making summer drives unbearable. Regular maintenance shouldn't be overlooked—checking the filter condition every six months can extend its lifespan.
Determining whether a compressor is good or bad is actually not difficult. I can handle it with a few simple methods. First, listen to the sound: after the engine starts and the air conditioning is turned on, there should be no abnormal noise from the compressor location, only smooth operation. Normally, it should produce a low humming sound; if there are sharp noises or rattling sounds, it likely indicates a fault. Second, check the cooling effect: after warming up the car, turn the air conditioning to maximum. If the airflow is not cold or even becomes hot, the compressor may be inefficient or stuck. Third, manually check the tension of the belt. If it's loose or worn, it can cause slipping and affect performance. A more reliable method is to measure the current or pressure values. Use a multimeter to check that the resistance remains stable within a few tens of ohms, and use a pressure gauge to ensure the high and low pressure differences are within the normal range. These tools can be purchased for a small cost, but be sure to operate safely and avoid touching high-pressure components. If you notice signs of oil leakage or a decrease in coolant, repair it early to avoid more serious issues. Finally, remember that compressor problems often stem from insufficient system maintenance, so regularly cleaning the radiator is key.
