What are the reasons for abnormal noises when the air conditioning is turned on?
4 Answers
Abnormal noises occur due to air conditioning malfunctions. The faults causing abnormal noises in the air conditioning system are as follows: Reasons for abnormal noises in the indoor unit of the air conditioner: High pressure in the air conditioning system's high-pressure pipe. The condenser is dirty, leading to poor heat dissipation. The expansion valve is blocked, causing high pressure in the pipeline. Key points for troubleshooting air conditioning faults: Observe the working conditions of both the indoor and outdoor units, and check various data of the air conditioner. Diagnosis of air conditioning faults: Refrigeration system: Inspect the refrigeration system pipelines for cracks, damage, frost, or condensation. Check for collisions or friction between pipelines and the casing, especially at welded joints and connection points of refrigerant pipelines. Any leakage will show oil stains. You can also use a clean soft cloth or paper to wipe the welded and connected areas to check for oil stains and determine if there is a leak. Electrical system: Check if the fuses in the electrical system are blown, if the insulation of electrical wires is intact, if the circuit board is cracked, or if connections are loose. Pay special attention to electrical connections to ensure good contact, as screws and connectors can easily loosen and cause poor contact. Ventilation system: Inspect if the air filter, heat exchanger coils, and fins are excessively dusty. Ensure the air intake and outlet are unobstructed. Check if the fan and blades are operating normally and if the airflow is adequate.
When the air conditioning is turned on and there is an abnormal noise, it is usually a problem with the blower system, such as foreign objects stuck in the fan blades or worn bearings, causing squeaking or clicking sounds. A loose compressor belt can also cause humming or screeching noises under the hood, especially when the AC is activated. If there is abnormal refrigerant flow, such as restricted gas movement, it can produce a hissing sound. I recommend first identifying the source of the noise—sounds from below the dashboard often originate from the blower, while noises under the hood involve the compressor or belt. Don’t delay, as this could lead to more severe issues like a damaged fan motor or even AC failure. Promptly visit a repair shop for inspection, cleaning, or part replacement. Regular maintenance, such as keeping the AC air intake clean, can effectively prevent such issues.
My car had this issue too, making an annoying squeaking noise whenever the AC was turned on. A friend suggested it might be leaves or small stones stuck in the blower fan, causing friction and noise when it runs. Another possibility was a clogged cabin air filter obstructing airflow, resulting in a wheezing sound. Worn or loose belts are also a common culprit, producing creaking noises. Don't underestimate these abnormal sounds—they could worsen and lead to excessive strain on the compressor, requiring major repairs. Since then, I've made it a habit to have a mechanic clean the air ducts and replace old belts every six months, and the noise has basically disappeared, saving me both money and hassle.
The annoying noise from the AC is usually caused by issues with the blower motor or vibration in the compressor's refrigerant pipes. Debris obstructing the fan blades can also create noise, as can a loose belt. It's recommended to first try cleaning the AC vents yourself. If that doesn't work, take it to a professional shop for adjustment. Addressing it early prevents increased wear on parts and higher repair costs.
