What are the causes of abnormal noise from the air conditioning compressor?
4 Answers
The causes of abnormal noise from the air conditioning compressor are: 1. Excessive or insufficient refrigerant charge, resulting in flow noise when passing through the expansion valve; 2. Insufficient lubricating oil inside the compressor, leading to friction noise due to inadequate lubrication; 3. Resonance between the compressor and other components in the belt drive system at certain speeds, causing abnormal noise; 4. Significant suction and discharge pulsation of the compressor itself, which is transmitted through the air conditioning pipelines to the air conditioning box and amplified, producing noise. The function of the air conditioning compressor is to compress and transport refrigerant vapor. Its working principle is: it sucks in low-temperature and low-pressure refrigerant gas from the suction pipe, compresses it through the operation of the motor-driven piston, and then discharges high-temperature and high-pressure refrigerant gas to the discharge pipe, providing power for the refrigeration cycle.
I've been repairing cars for many years and have encountered quite a few cases of abnormal noises from air conditioning compressors. The common causes are, first, wear and tear on the compressor's own bearings or internal gear damage, which can produce clicking or grinding sounds when rotating. Second, belt issues, such as aging, slackness, or excessive tightness, can cause squeaking noises during operation. If the refrigerant is too low or too high, causing an imbalance in system pressure, the compressor's load increases significantly, potentially resulting in a dull noise. Additionally, loose mounting brackets or vibrations from other engine components transmitting to the compressor can also be culprits. You can initially identify the issue by listening to the sound's location, but I recommend not tinkering with it yourself—get it checked at a professional shop as soon as possible. Addressing the problem early prevents the noise from worsening and avoids complete compressor failure, which would be costly to replace. Moreover, regular maintenance of the air conditioning system can prevent issues; just check the belt and refrigerant levels once a year.
When I first bought the car, the AC compressor made a squeaking noise, which really startled me. After checking, it turned out the belt was too loose. The mechanic tightened it, and the noise improved significantly. Common causes include shattered compressor bearings or internal jamming, which can produce metal grinding sounds when the AC is on. If the belt is worn or cracked, slipping can also create annoying noises. Insufficient refrigerant due to leaks or overcharging can cause uneven system pressure, making the compressor unstable and noisy. Loose mounting screws causing vibrations might also be the culprit. While driving, avoid frequently turning the AC on and off to reduce stress. Address the issue early—otherwise, the noise will worsen and make driving uneasy. Before summer arrives, it's best to get a full inspection at the shop, keep the system clean, and extend the compressor's lifespan, saving both money and hassle.
Abnormal noise from the air conditioning compressor is mainly caused by internal wear such as bearing damage, or loose and slipping belts. Pressure imbalance due to refrigerant issues can also lead to noise. Loose brackets or unstable installation causing vibration and noise transmission should not be overlooked. Upon discovery, immediate inspection is necessary to prevent minor issues from becoming severe. Maintenance advice is straightforward: regularly check belt condition, clean the condenser, ensure the refrigerant is at the proper level, and prioritize safety.
