Why Does the Car Air Conditioner Make Abnormal Noises?
3 Answers
There are two main reasons why a car air conditioner emits abnormal noises, which can be categorized into two situations based on the different sounds: 1. The metal friction sound produced when the compressor electromagnetic clutch engages; 2. The squeaking sound caused by excessive force on the air conditioner belt. Diagnostic process: 1. Analysis One: When the compressor electromagnetic clutch engages and produces a metal friction sound, the fault is generally due to a lack of lubricating refrigerant oil inside the compressor. When refrigerant oil is insufficient, the internal piston of the compressor does not receive adequate lubrication during operation, resulting in a metal friction sound under the high pressure of the refrigerant. Another scenario is a fault with the electromagnetic clutch itself, where the internal bearing is damaged, causing abnormal noise. In this case, the compressor must be replaced. If refrigerant oil is lacking, it is necessary to first recover the refrigerant from the air conditioning system, evacuate the system, refill with sufficient refrigerant oil, then recharge the refrigerant, and run the air conditioner for a while to allow the refrigerant oil to circulate fully in the system. If the friction is severe, the compressor may also need replacement. 2. Analysis Two: The air conditioner belt makes abnormal noises when the air conditioner is turned on. This situation occurs when the air conditioning system pressure rises rapidly upon activation.
I've also encountered strange noises from the air conditioning in my previous car. Usually, it's because there's debris stuck in the fan, like leaves or small stones that got sucked in, causing a squeaking sound when rotating. Another common issue is worn-out compressor bearings, which become noisy over time due to aging, especially noticeable when starting the AC or accelerating. Additionally, the problem might be with the belt—if it's loose or cracked, it can produce a whining sound as it slips on the pulley. I usually check around the fan blades for any debris and clean it out, which often solves the problem. However, if the noise is sharp or persistent, it's best to take it to a professional mechanic to inspect the compressor or system piping. Ignoring minor issues can lead to bigger problems, affecting the AC's cooling efficiency or even vehicle safety. After all, driving without AC in summer can be quite uncomfortable.
Having driven for decades, I've found that most abnormal noises in the air conditioning system are caused by dirt buildup, especially around the blower where dust accumulates. When the fan wheel rotates, it produces a buzzing sound like a flying bee. Another common issue is insufficient refrigerant, leading to unstable system pressure that makes the compressor produce a tapping sound. Loose pipes are also a frequent culprit, creating clanking noises when driving over bumpy roads. I regularly clean the AC filter myself to reduce debris accumulation. If inspection reveals aged belts or worn fan motors, I replace the parts promptly to avoid roadside breakdowns. After all, AC noises aren't just annoying - they might strain the battery system too. So never ignore these minor sounds, just schedule a comprehensive check when possible.
