Why is the car air conditioning fan making loud noises?
3 Answers
Car air conditioning fan is making loud noises. The reason is that the air filter has not been replaced for a long time, and there are foreign objects such as leaves in the air duct. Solution: Open the air filter cover under the toolbox on the passenger side, cover it with a gauze bag, start the car, and turn the fan to the maximum setting to blow out the foreign objects. Alternatively, a repair shop can use high-pressure airflow to remove the foreign objects. Below are other noises and their solutions: 1. Internal noises in the car air conditioning: Internal noises mainly come from inside the dashboard, and the reasons are as follows: 1. Normal noise: A noise similar to the sound of flowing water comes from the glove box when the air conditioning is turned on. This is the air conditioning expansion valve working, which is a normal phenomenon. 2. Air or moisture in the refrigerant: If there is air or moisture in the refrigerant of the air conditioning compressor, noise will be produced when the refrigerant evaporates and expands. Solution: Extract and replace the refrigerant. 2. External noises in the car air conditioning: 1. Compressor lacks lubricating oil: When the compressor lacks lubricating oil, or the lubricating oil is not used properly, severe noise will occur inside the compressor, and it may even cause the compressor to wear out and become unusable. Solution: In this case, check whether the clutch is slipping or if there is a problem with the transmission belt, and check whether the lubricating oil is being used properly. 2. Damaged bearing in the electromagnetic clutch: The electromagnetic clutch of the compressor is also a common source of noise. The compressor often operates under high load, changing speed from low to high, so the requirements for the electromagnetic clutch are very high. Moreover, the electromagnetic clutch is usually installed close to the ground and often comes into contact with rain and mud. When the bearing inside the electromagnetic clutch is damaged, noise will be produced. Solution: First, check the air conditioning belt to confirm whether the installation screws are loose, whether the belt is oily, or whether the belt is worn. If the electromagnetic clutch is problematic, simply replace the electromagnetic clutch. 3. Engine oil leakage: Check whether the engine is leaking oil. Solution: Add engine oil.
Last time during maintenance, the mechanic told me that there are usually several reasons for loud car air conditioning fan noise. The most common one is dust and oil buildup on the fan blades, causing unbalanced rotation and abnormal sounds, which is particularly noticeable when we frequently drive on dirt roads. Another reason is worn fan bearings, which older cars are prone to experience, producing a humming sound that changes with fan speed. Sometimes, issues with the fan motor can also cause noise, requiring checks for aging wiring or internal motor faults. Another easily overlooked situation is the fan blades hitting foreign objects, such as small branches or plastic bags, which can be resolved by cleaning. I suggest first turning off the engine and opening the hood to inspect the fan area. If there are no foreign objects, then take it to a repair shop for a thorough check-up. Don't wait until the air conditioning fails during hot weather to panic.
I just encountered the same issue at the repair shop. The technician analyzed that there are three common factors for loud noises from the AC fan. First, the fan itself may be deformed or loose, causing instability and a whooshing sound at high speeds. Second, debris blocking the air intake can obstruct the airflow, producing a whistling-like noise. Third, a worn or improperly tensioned compressor belt can indirectly affect the fan speed and cause noise. On-site, he taught me to record the characteristics of the abnormal sound with my phone: a humming noise may indicate bearing issues, a clicking sound could be blade collisions, and a high-pitched whine often points to excessive motor load. The repair solution is straightforward—first clean the airflow path of debris, then adjust the belt tension, and only consider replacing fan components as a last resort to minimize costs.
