What Causes the Abnormal Noise in a Car's Air Conditioning Blower?

[MadisonLynn]

Car air conditioning blower abnormal noise is caused by: 1. Damaged compressor belt tensioner; 2. Excessive wear or damage to the blower motor; 3. Malfunction of the internal/external circulation motor; 4. High pressure in the air conditioning system; 5. Incomplete engagement of the compressor clutch; 6. Long overdue replacement of the air conditioning filter. Solutions for abnormal noise in car air conditioning blowers: 1. Timely cleaning of air conditioning vents; 2. Removing fan blades for lubrication and debris removal; 3. Replacing the blower with a new one; 4. Replacing the air conditioning filter. The working principle of car air conditioning is: The compressor sucks in low-temperature and low-pressure refrigerant gas from the evaporator outlet and compresses it into high-temperature and high-pressure gas before discharging it from the compressor.

[McJameson]

The last time I encountered this situation was during an inspection of an old car at the shop. There are usually several common reasons for abnormal noises from the blower. Debris like leaves or small stones stuck in the blades can cause a flapping or clicking sound when rotating; prolonged use leading to dry friction due to lack of lubrication in the bearings can result in a squeaky, harsh noise; deformed fan blades causing imbalance can lead to shaking and abnormal sounds; a severely clogged filter causing abnormal blower speed can produce a whooshing sound; or it could be an issue with the motor coil, resulting in a buzzing noise. These abnormal sounds are not only annoying but also indicate that the blower's lifespan is nearing its end, especially when the air conditioning is used for long periods during summer. I usually advise car owners not to delay when they hear such noises—first, turn off the blower and check if the filter needs replacement. If the fan blades are visible, clean out any debris. If the issue persists, the blower assembly may need to be disassembled for repair or parts replacement. Regularly cleaning the air conditioning intake vents can indeed help reduce such occurrences.

[OCarmen]

My car's air conditioning also had a buzzing noise before, and the repair shop technician explained it quite clearly. The main causes of blower noise fall into three categories: foreign objects caught in the impeller, bearing wear, or fan blade deformation. In my case, it turned out to be insufficient lubrication in the bearing causing friction noise during blade rotation, and the replacement cost over 300 yuan. The technician also mentioned that a clogged cabin air filter can force the blower to spin at high speed, generating wind noise that's often mistaken for a malfunction. Identifying the type is actually quite simple: a clicking sound usually means foreign objects stuck in the blades; a buzzing friction noise indicates bearing failure; while a howling wind noise mostly suggests a clogged filter or air duct issue. It's recommended to replace the cabin air filter at least once a year, and try to avoid parking under large trees to prevent leaves from falling into the air intake. Bearing damage is related to vehicle age, so cars over five years old require more frequent regular inspections.

[McMorgan]

I've gained some insights from studying car air conditioning systems, and most abnormal fan noises stem from mechanical failures. There are four common causes: blades hitting the inner wall when leaves or paper debris get caught on the impeller; dry and worn ball bearings creating friction noise; deformed fan blades causing air vortex noise; and high-frequency vibration sounds from eccentric motor shafts. Non-failure situations include muffled wind howling when the cabin air filter is clogged with willow catkins. Last time I helped a friend troubleshoot, we found biscuit crumbs dragged by mice stuck in the blades - cleaning them restored quiet operation. When diagnosing, pay attention to noise characteristics: crisp impact sounds indicate foreign objects; mechanical grinding noises suggest bearing issues; whistling sounds point to blade deformation. DIYers can remove the glove compartment to check for clogged filters, but bearing failures require professional repair. I recommend having technicians inspect the fan condition during every maintenance service.

[Mckenzie]

After spring started, my car's air conditioning began making a squeaking noise. I consulted experienced drivers and finally understood the reasons. The main cause is the drying out or damage of lubricating oil in the blower bearings after long-term operation, resulting in particularly harsh metal friction sounds during rotation. This is common in cars over five years old. Another reason is the sound of leaves or paper debris getting stuck in the blades and causing collisions during rotation, often occurring during seasonal changes when parked outdoors. Additionally, if the air filter hasn't been replaced in two or three years, accumulated dust increases the blower's load, causing a roaring sound. When encountering abnormal noises, it's recommended to troubleshoot in three steps: first replace the air filter, then check the blower impeller for foreign objects, and finally inspect the bearing condition. Last month, after I removed the leaves, the noise disappeared. Daily precautions include avoiding parking near trash bins and turning off the air conditioning's external circulation after parking to reduce debris inhalation.