The failure to cool down or insufficient air-conditioning in the car air conditioner is a common fault of the air conditioner. It is more common in the sealing problem of the refrigeration system, because the refrigerant R134a used in modern cars is highly permeable. To sum up, there are three main aspects:
The mechanical failure of the air-conditioning system, the electrical circuit failure of the air-conditioning system, and the failure of the refrigerant and refrigerating oil.
1. Mechanical failure of air conditioning system
1. Compressor failure
(1) Transmission Whether the belt is aged, cracked, slack or too tight can affect power transmission.
(2) The internal parts are damaged or worn, which affects the compression performance, which is manifested as abnormal noise inside the compressor.
(3) The compressor cylinder gasket is blow-by, and the intake and exhaust valves are damaged, which affects the compression performance.
2. Condenser and fan failure
(1) Whether the heat sink is covered with oil and dust, which affects heat dissipation.
(2) Whether the fan is running well.
3. Failure of the blower
Whether the operation is normal, which may lead to insufficient air flow.
4. Liquid storage dryer
It contains filter screen and desiccant. Whether the filter screen is blocked may affect the flow of refrigerant; whether the desiccant is invalid, affecting the water absorption capacity, which may cause ice blockage. Normal desiccant is blue, desiccant saturated with water is red.
5. Expansion valve failure
The flow of liquid refrigerant entering the evaporator is controlled by opening and closing the valve port of the expansion valve to regulate refrigeration effect of quantity. If the valve port is always opened too large, the inflow of refrigerant is large, and the surface of the evaporator is frosted due to subcooling, resulting in a long-term stop of cooling; if the valve port is always opened too small, the inflow of refrigerant is small, resulting in insufficient cooling.
6. Evaporator
Whether the heat sink is covered with oil and dust, which affects heat exchange; whether it is deformed, etc.