What Causes Abnormal Noises in the Car Air Conditioning?
3 Answers
There are several reasons for abnormal noises in the car air conditioning: 1. Refrigerant flow noise: This is the noise caused by the throttling of the expansion valve before the evaporator in the car air conditioning system. Simply adjusting the operating conditions slightly, such as changing the fan speed, can make the noise disappear. 2. Modal matching issue: This is a modal matching problem between the evaporator and the expansion valve. At a certain operating frequency, the refrigerant flow and the pipeline resonate, producing noise, similar to how water pipes sometimes make rattling noises, which stop when the tap is turned on. This noise does not affect the cooling performance, so there is no need to worry.
I've encountered abnormal noises from the car air conditioner several times, mostly due to issues with the fan system, such as dust or small stones stuck on the blades, causing a clicking sound when rotating. There are also compressor problems, like insufficient lubrication or wear, which can produce a squeaking noise. I remember the last time my car had a similar sound, and the inspection revealed that the air conditioner filter was too dirty, causing uneven airflow and forcing the fan to work extra hard. I recommend regularly cleaning the filter and replacing it at least once a year to avoid the accumulation of debris. Additionally, a loose belt can also cause abnormal noises, especially noticeable during startup. Ignoring these small issues for a long time may burn out the fan, and repairs can be costly. For safety, it's best to have it checked at a professional shop.
I noticed a strange noise from the AC while driving. Common causes could be a faulty blower motor or unbalanced fan blades. The first time I heard it, I thought it was a major issue, but later found leaves stuck in the fan—removing them fixed it. A clogged filter can also reduce airflow and cause a whooshing noise. I find these noises quite annoying, especially on long trips where they affect my mood. A simple self-check is to turn off the AC and listen for the source—if it's from the vents, cleaning might solve it. Don’t forget to check if the belt is worn; a loose belt can produce a squeaking sound. For prevention, I make it a habit to service the AC after winter—it saves money and hassle.
