The air conditioning compressor is used to circulate the refrigerant in the system
The compressor shaft is installed in the aluminum front housing cover on bearings and sealed on the side of the drive pulley with an oil seal.
The compressor drive pulley is mounted on a double-row ball bearing and constantly rotates when the engine is running.
When the air conditioner is turned on, the torque is transmitted from the pulley to the compressor shaft through a friction clutch with an electromagnetic drive.
If the system is working, when the air conditioner is turned on, a click is heard - this is the clutch pressure plate, under the action of an electromagnet, engages with the drive pulley, and the compressor rotor starts to rotate.
But during the operation of the air conditioner, the following compressor malfunctions may occur.
If, when the air conditioner is off, the clutch makes extraneous sounds during rotation, heats up or smells of burning, then its bearing has probably begun to collapse.
In this case, the bearing must be replaced.
In some advanced cases, it may be necessary to replace the compressor clutch assembly or its components.
If you don't hear a click after turning on the air conditioner, then the following problems may occur:
- - a refrigerant leak has occurred and the control system is blocking the compressor from turning on;
- - the pressure sensor in the system has failed;
- - malfunctions in the electrical circuits of the control system;
- - the winding of the coil of the clutch electromagnet burned out;
- - the engine control unit for some reason (high engine coolant temperature, high engine speed) has blocked the compressor from turning on.
If the clutch rotates easily and freely, but when the air conditioner is turned on, extraneous noises are clearly audible or the engine even stalls, then the compressor is most likely stuck.
The internal pump part of the compressor cannot be repaired.
In this case, the compressor will have to be replaced.
If a click is heard, the clutch easily rotates the compressor shaft, and there is no coolness in the cabin.
In this case, it only seems that the compressor is working, but in reality it is not pumping anything.
Only an experienced specialist with special control and diagnostic equipment can establish the truth.
The cause of the malfunction can be most accurately determined after a complete diagnosis at a specialized service center for the repair of automotive air conditioners.
Removing the air conditioning compressor
We install the car on a viewing ditch or lift
Remove the accessory drive belt (article - Replacing the accessory drive belt Nissan Almera)
We remove the protection of the power unit (article - Removing the protection of the Nissan Almera power unit)
Removing the front bumper (article - Removing the bumpers of a Nissan Almera car)
We discharge the air conditioning system, for this:
- we release the refrigerant through valve 1 of the low pressure pipeline and valve 2 of the high pressure pipeline;
- unscrew the protective caps of the valves and press the valve stems with a suitable tool (we work in goggles).
If it is necessary to replace the valve, unscrew it from the pipeline fitting with a key, the same as the wheel valve cap
Remove the valve
Valve for charging and discharging refrigerant
Disconnect tip 2 wires from terminal 1 of the compressor electromagnetic clutch
With a head of 10, we unscrew the bolt securing the flange of the refrigerant supply pipe to the compressor
We remove the tip of the refrigerant supply pipe from the compressor hole
Remove the rubber o-ring from the tip of the tube
Having unscrewed the bolt of the refrigerant outlet pipe flange to the compressor with a 10 wrench
Remove the tip of the tube from the compressor hole
Remove the rubber sealing ring from the tip of the tube
With a 10 head, unscrew the four bolts securing the compressor to the engine bracket
Removing the compressor
Before installing the compressor, we replace the sealing rings of the tips of the refrigerant inlet and outlet pipes with new ones.
Install the air conditioning compressor in reverse order
We charge the system with refrigerant and check the operation of the air conditioner at the maximum fan speed of the heater.
Replacing the compressor drive pulley bearing and replacing the compressor clutch electromagnet can be found in the article - Removing and repairing the air conditioning compressor.