The car compressor is broken. Should we have it repaired or replaced?
Whether to repair or replace the car compressor depends on the type of fault, the cost of repair, and the condition of the vehicle: minor faults (such as poor lubrication, slight leakage) are better repaired as they are more economical; major faults (such as internal damage, severe leakage) are better replaced as they are more reliable.
Fault type determines the core choice
Priority repair scenarios (low cost, easy repair):
External minor faults: such as a burned-out clutch coil (there is a strange noise when turning on the air conditioning but it does not cool), poor contact of the circuit or failure of the sensor, which can be restored to normal operation for 3-5 years.
Minor issues: insufficient lubrication, damaged drive belt or slight refrigerant leakage, the repair cost is only 300-800 yuan.
Must replace scenarios (repair ineffective or high risk):
Internal mechanical damage: piston stuck, bearing wear (with metal friction sound), repair can lead to recurrence and cost over 1500 yuan, replacing the new compressor has a durability of 5-8 years.
Severe leakage or shell rupture: rapid loss of refrigerant (smelling "medicine" within minutes), cannot be reliably repaired, replacing can avoid secondary damage.
According to different working principles, air conditioning compressors can be classified as fixed-displacement compressors and variable-displacement compressors.
Fixed-displacement compressor
The displacement of the fixed-displacement compressor increases proportionally with the increase of engine speed. It cannot automatically change the power output according to the cooling demand, and has a relatively large impact on engine fuel consumption. Its control is generally achieved by collecting the temperature signal from the outlet of the evaporator. When the temperature reaches the set value, the electromagnetic clutch releases, and the compressor stops working. When the temperature rises, the electromagnetic clutch engages, and the compressor starts working. The fixed-displacement compressor is also controlled by the pressure in the air conditioning system. When the pressure in the pipe is too high, the compressor stops working.
Variable-displacement air conditioning compressor
The variable-displacement compressor can automatically adjust the power output according to the set temperature. The air conditioning control system does not collect the temperature signal from the evaporator outlet, but controls the compressor's compression ratio based on the pressure change signal in the air conditioning pipe to automatically adjust the outlet temperature. During the entire cooling process, the compressor is always working, and the regulation of cooling intensity completely relies on the pressure regulating valve installed inside the compressor to control. When the pressure at the high-pressure end of the air conditioning pipe is too high, the pressure regulating valve shortens the piston stroke in the compressor to reduce the compression ratio, thus reducing the cooling intensity. When the pressure at the high-pressure end drops to a certain level and the pressure at the low-pressure end rises to a certain level, the pressure regulating valve increases the piston stroke to increase the cooling intensity.
The main reasons for abnormal noise from the car compressor include:
Electromagnetic clutch failure
Bearing damage: The clutch is located near the ground and is prone to erosion by rain and dirt, resulting in bearing wear and abnormal noise.
Abnormal installation gap: A too large gap will increase impact noise, while a too small gap will cause movement interference, and it needs to be adjusted to the standard range (usually 0.5-1.5mm).
Transmission system problems
Abnormal belt condition:
Loose or aging belts cause slipping and shaking, resulting in "clattering" sounds.
Insufficient tension of the tensioner wheel needs to be replaced, and the belt needs to be updated as a whole.
Misalignment of the gear train: The compressor and the generator pulley are not in the same plane, accelerating the wear of the belt.
Lubrication and refrigerant abnormalities
Insufficient lubricating oil: Low refrigerant oil level causes internal dry friction, resulting in sharp abnormal noise, and requires replenishing with special lubricating oil.
Refrigerant problems:
Excessive or insufficient addition causes flow sound of the expansion valve.
High system pressure (>250psi) or containing air/moisture, need to be detected and adjusted.
If you want to know more, keep reading the other articles on this site!
Please call us if you need such products.
Zhuo Meng Shanghai Auto Co., Ltd. is committed to selling MG&MAXUS auto parts welcome to buy.
