The arrival of the hot summer has made car owners more and more dependent on car air conditioners. However, the air conditioner often fails in one way or another. If the car owner wants to repair it by himself, he still needs to learn some tricks.
Automotive air conditioner not cooling or insufficient air conditioner is a common fault of air conditioner, which is more common in the sealing problem of refrigeration system, because the refrigerant R134a used in modern cars has strong permeability. To sum up, there are three main aspects: air-conditioning system mechanical failure, air-conditioning system electrical circuit failure, refrigerant and refrigerated oil failure.
I. Mechanical failure of air conditioning system
The mechanical failure of air conditioning system mainly includes compressor failure, condenser and fan failure, blower failure, liquid storage dryer , Expansion valve failure and evaporator failure. Judging whether it is a compressor failure depends on whether the transmission belt is aging, cracked, loose or too tight, which affects the power transmission. The internal parts are damaged or worn, which affects the compression performance, which is manifested as abnormal noise inside the compressor. Compressor cylinder head blow-by gas, damaged intake and exhaust valves, affecting compression performance.
The failure of the condenser and fan mainly depends on whether the heat sink is covered with oil and dust, which affects the heat dissipation. Whether the fan is working well. The blower failure depends on the normal operation, which may result in insufficient supply air flow. The liquid receiver dryer contains a filter screen and a 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. The failure of the expansion valve depends on the opening and closing of the expansion valve port to control the flow of liquid refrigerant entering the evaporator, which plays a role in regulating the cooling capacity. 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 supercooling, resulting in the cooling stop for a long time; if the valve port is always opened too small, the inflow of refrigerant is small, resulting in insufficient cooling. The evaporator depends on whether the heat sink is covered with oil and dust, which affects the heat exchange; whether it is deformed, etc.
Second, the electrical circuit failure of the air conditioning system
pressure sensor, temperature sensor, thermostat, compressor electromagnetic clutch, high and low pressure protection switch, expansion valve Thermometer etc.
Three, failures caused by refrigerant and refrigerating oil
There are many reasons for failures caused by refrigerant and refrigerating oil, including insufficient cooling caused by too much refrigerant , Insufficient cooling caused by too little refrigerant, excessive impurities in refrigerant and refrigerating machine oil, and insufficient cooling capacity caused by micro-blocking, insufficient cooling caused by water infiltration in the air-conditioning refrigeration system, insufficient cooling caused by air in the system, and poor quality refrigeration Oil causes insufficient cooling, etc.