What Causes the Abnormal Noise When Turning on the Car Air Conditioning?

[StFelix]

Reasons for abnormal noise when turning on the car air conditioning include excessively high pressure in the high-pressure pipe of the air conditioning system, dirty condenser, poor heat dissipation, blocked expansion valve, and high pressure in the pipes. Key points for air conditioning fault inspection: Observe the working conditions of the indoor and outdoor units: For example, check the display status of the indicator panel, whether the indoor unit is working, whether the fan speed output is normal, and whether the outdoor fan and compressor are running to determine whether the issue is electrical or system-related causing the lack of cooling. Measure various data of the air conditioner: Such as water leakage from the air conditioner, the temperature difference between the air inlet and outlet (the normal temperature difference should be 12-14 degrees). However, due to environmental humidity and temperature influences, the data can only serve as a reference value. Diagnosing air conditioning faults: Refrigeration system: Inspect each pipeline of the refrigeration system for cracks, damage, frost, or condensation. Check for any contact or friction between refrigeration pipelines or between pipelines and the casing, especially at the welding points of the refrigerant pipelines and connection joints for leaks. Any leakage point will have oil stains. You can also use a clean soft cloth or paper to wipe the welding points and connection joints to check for oil stains to determine if there is a leak. Electrical system: Check if the fuse in the electrical system has blown, whether the insulation of electrical wires is intact, whether the circuit board is broken, or if connections are loose. Pay special attention to whether electrical connections are secure, as screws and connectors can easily become loose, leading to poor contact. Ventilation system: Observe whether the air filter, heat exchanger coils, and fins are excessively dusty; check if the air inlet and outlet are unobstructed; ensure the fan and blades are functioning normally; and verify whether the airflow is normal.