There are many reasons why a car's air conditioner makes a thumping noise after running for a while, including engine belt slippage, air conditioner compressor failure, clutch failure, etc. The following are the reasons why the car's air conditioner makes a noise after running for a while: 1. Engine belt slippage: The car's air conditioner compressor is driven by the engine. If the engine belt slips, the air conditioner compressor may not work properly, and the car's air conditioner will make a thumping noise. Engine belt slippage is mostly caused by belt aging. This situation can be resolved by promptly replacing the engine belt. 2. Air conditioner compressor failure: If there is a noise after the air conditioner reaches the set temperature, this is because the air conditioner compressor stops working, which is a normal phenomenon and can be ignored. If there is a continuous noise, it is mostly due to a problem with the air conditioner compressor. There are many reasons for air conditioner compressor failure, and it is necessary to go to a repair shop or 4S store for professional inspection and repair. 3. Clutch failure: If the clutch is not properly fixed, when the air conditioner is turned on, the engine load will increase, which will affect the clutch vibration and cause noise. This situation requires re-fixing the clutch. If the clutch is worn, the clutch three-piece set must be replaced immediately.
