Why is the air conditioning noise particularly loud when the car is running?

[DiGriffin]

The reasons for particularly loud air conditioning noise when the car is running include the following: 1. Abnormal noise from the air conditioning pump: Any issue with either the electromagnetic clutch or the bearings inside the air conditioning pump can cause abnormal noise. The noise from the electromagnetic clutch is mainly caused by wear leading to increased clearance, while the noise from the air conditioning pump bearings is primarily due to insufficient lubrication. In severe cases, this can lead to the air conditioning pump burning out, rendering it unable to perform cooling functions. 2. Dirty or stuck throttle valve: Turning on the air conditioning increases the engine load, requiring the engine to widen the throttle opening to allow more air intake. If the throttle valve has carbon buildup or is stuck, it can cause engine shaking and abnormal noise. 3. Improper tension of the compressor drive belt: If the tension of the drive belt is incorrect, it can cause abnormal noise in mild cases and damage the air conditioning compressor in severe cases. The principle is that if the drive belt is too loose, the electromagnetic clutch will slip; if the drive belt is too tight, the load on the electromagnetic clutch will increase.