What Causes Noise in Car Air Conditioning?

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The causes of noise in car air conditioning can be divided into internal and external noises within the air conditioning system. Below are detailed explanations and solutions: 1. Internal noise in car air conditioning: Internal noise mainly comes from the dashboard area, with the following possible causes: 1. A sound similar to flowing water is heard from the glove box when the air conditioning is turned on. This is the normal operation of the air conditioning expansion valve. 2. Noise within the air conditioning ducts. The air filter has not been replaced for a long time, or there are foreign objects like leaves in the ducts. Solution: Open the air filter cover under the passenger side toolbox, cover it with a gauze bag, start the car, and set the fan to the highest setting to blow out the foreign objects. Alternatively, a repair shop can use high-pressure air to remove the objects. 3. Air or moisture in the refrigerant inside the air conditioning compressor, causing noise during refrigerant evaporation and expansion. Solution: Extract and replace the refrigerant. 2. External noise in car air conditioning: 1. When the compressor lacks lubricating oil or the oil is used improperly, severe noise may occur inside the compressor, potentially leading to wear and failure. Solution: In such cases, check if the clutch is slipping, inspect the drive belt, and ensure the lubricating oil is used correctly. 2. The compressor electromagnetic clutch is another common source of noise. The compressor often operates under high load, shifting from low to high speeds, placing high demands on the electromagnetic clutch. Additionally, the clutch is usually installed close to the ground and frequently exposed to rain and dirt. If the bearings inside the clutch are damaged, noise will occur. Solution: First, check the air conditioning belt to confirm if the mounting screws are loose, if the belt is oily, or if it is worn. If the electromagnetic clutch is faulty, it should be replaced. 3. Check if the engine is leaking oil. Solution: Top up the engine oil.