Why Does the Car Fan Suddenly Become Very Loud When the Air Conditioning is On?
3 Answers
When the car's air conditioning fan becomes very loud, the reason is usually that the air filter has not been replaced for a long time, or there are foreign objects such as leaves in the air duct. Solution: Open the air filter cover under the glove compartment, cover it with a gauze bag, start the car, and turn the fan to the highest setting to blow out the foreign objects. Alternatively, a repair shop can use high-pressure airflow to remove the debris. Below are other possible noises and their solutions: 1. Internal Noise in the Car Air Conditioning: Internal noises mainly come from the dashboard and can be caused by the following: a. Normal noise: A sound similar to flowing water coming from the glove compartment when the air conditioning is on. This is the expansion valve working and is normal. b. Air or moisture in the refrigerant: If there is air or moisture in the refrigerant of the air conditioning compressor, it can cause noise during evaporation and expansion. Solution: Replace the refrigerant. 2. External Noise in the Car Air Conditioning: a. Compressor lacks lubrication oil: When the compressor lacks lubrication oil or the oil is improperly used, severe noise can occur inside the compressor, even leading to wear and damage. Solution: Check if the clutch is slipping or if there is an issue with the drive belt, and ensure the lubrication oil is used correctly. b. Damaged bearing in the electromagnetic clutch: The electromagnetic clutch of the compressor is another common source of noise. The compressor often operates under high load, shifting from low to high speeds, which places high demands on the electromagnetic clutch. Additionally, the clutch is usually installed close to the ground and frequently exposed to rain and dirt, leading to bearing damage and noise. 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, replace it. c. Engine oil leakage: Check if the engine is leaking oil. Solution: Top up the engine oil.
I've been driving for over twenty years and have encountered situations where the air conditioning fan suddenly becomes louder many times. This is usually a normal phenomenon caused by the fan operating at high speed when the air conditioning is under heavy load, but abnormal volume may indicate a problem. The most common reasons are leaves or dust accumulated on the fan blades causing noise when rotating, or the fan motor becoming loose due to aging. I suggest stopping the car first, opening the hood, and carefully checking the fan area for any foreign objects entangled; try a simple cleaning. If the noise persists, it might be due to poor condenser heat dissipation or voltage instability causing motor overload, and it's necessary to visit a repair shop promptly. Don't overlook this small issue, as fan failure can lead to engine overheating, damaging the car and costing money, not to mention the danger. Regular maintenance and cleaning of the engine compartment can make the car last longer and be more worry-free.
As a car owner who loves studying automotive structures, I believe that a sudden increase in the noise from the air conditioning fan is simply a sign of the fan system working at full capacity under high pressure. Normal noise during high-speed cooling is acceptable, but loud noises often indicate blade deformation, foreign object obstruction, or motor failure causing abnormal sounds. When the air conditioning refrigeration pressure is high, the fan speed surges, naturally increasing the noise; it could also be due to electrical issues like a relay malfunction causing the fan to go wild. I would first check if the fan rotates smoothly and manually clean any leaves or debris to see if there's improvement. Regular maintenance of the cooling system and condenser is crucial to prevent dust buildup from causing bigger problems. If you're handy, a minor disassembly and inspection is fine, but make sure to disconnect the power for safety. Remember, addressing small issues promptly can prevent motor burnout and costly repairs.
