How to Determine if an Automotive Air Conditioning Compressor is Good or Bad?
3 Answers
Here are the methods to determine if an automotive air conditioning compressor is good or bad: 1. The quality of the compressor, or its working efficiency, can be judged under normal conditions by connecting a three-way pressure gauge set. After starting the engine, if the low-pressure gauge needle drops rapidly and the high-pressure gauge needle rises quickly, and when the throttle is increased, the amplitude of these changes becomes even greater, it indicates good performance. Conversely, if the amplitude of these changes is not significant during the above operations, it suggests low efficiency and poor performance. 2. If the gauge needles show no noticeable changes at all, it indicates no efficiency, meaning the compressor may no longer be functioning properly.
I've been repairing cars for many years, and there are several common methods to determine if a car's air conditioning compressor is working properly. Start the engine and turn on the AC—the compressor should click and start running. If there's no movement or it doesn't turn, it's likely broken. Listen for any unusual noises, like squeaking or grinding sounds, which could indicate worn bearings. Check the cooling effect—if the air isn't cold or is warm, the compressor might be the issue. Also inspect the belt; if it's loose or broken, it won’t drive the compressor. Use a pressure gauge to measure the high and low sides: normal ranges are 150-250 psi for the high side and 30-40 psi for the low side. Significant deviations suggest refrigerant leaks or compressor failure. Voltage testing is also crucial—12-14V is normal; otherwise, there might be an issue with the clutch circuit. Additionally, check refrigerant levels and for leaks, as low refrigerant can strain the compressor and cause overheating. Regular maintenance, like replacing refrigerant and cleaning the system every two years, can prevent major repairs. Compressors typically last 8-10 years. If problems arise, take the car to a professional shop immediately—don’t attempt DIY fixes that could worsen the issue.
As an average driver, I think you can test the air conditioning compressor yourself. Turn on the AC while driving to see if the air is cool. If it takes too long to get cold or only blows warm air, the compressor might be failing. Park the car, open the hood, and listen near the compressor—normal operation should be quiet without strange noises. If you hear clunking or screeching, avoid driving further, as refrigerant leaks on the road can be dangerous. Check if the belt is tight and dry; a loose or broken belt means the compressor won’t work. Monitor refrigerant levels via gauges or sensors—low levels reduce cooling and overload the compressor. Last month, my car’s AC wasn’t cooling, and the shop found a faulty compressor clutch. It cost some money, but safety comes first. Before each summer, do a simple checkup and replace the filter to prevent compressor overload. Minimize inefficient AC use in hot weather to protect the compressor system for long-term reliability.
