Special Yu professional silicone oil fan clutch was informed that a Lexus 400 car,the driver of this car at high speed, the air conditioner to the automatic air outletgradually by the cold air into the hot air, and the wind is more and more big, the engine temperature increase, sometimes boil. The car, first connect the instrument of fault diagnosis, fault code reading, but no fault code display. Then start the engine, detection of normal temperature, air conditioning is good, no abnormalphenomenon. After a long time the road test, found in high speed, the air conditioning on both sides of the air outlet air gradually become hot. At the same time the coolant temperature, from data diagnosis instrument flow coolingtemperature readout has exceeded the limit value is 118 ℃, the air conditioning compressor was cut operation.
Special Yu professional silicone oil fan clutch of Lexus 400 car air conditioning system is fully automatic computer control. When the air conditioning automaticAUTO is switched on, set by the temperature TEMP switch to the required temperature, the ECU signal is transmitted light radiation angle input to the air conditioner according to the temperature inside the car, ambient temperature and solar control unit ECU, through ECU analysis and calculation, the output to control the power transistor. When the power transistor receives the signal sent by ECU,according to the output signal ECU, increase or decrease the speed of blower, air flow to control blower. And stop running compressor, refrigeration system ofrefrigerant circulation is unable to realize refrigeration, resulting in the outlet air. Itcan also eliminate the car air conditioning system failure is not the problem itself,the real fault point should be in the cooling system. Then, check the cooling system of engine, the engine is found to work at high temperatures, if you touch the engineby hand, sewer pipe, the temperature there is not much difference, so it can exclude the thermostat failure probability. In front of the two electronic fan at high temperature, are also high-speed operation, found no abnormalities.
In front of the two electronic fan at high temperature, are also high-speed operation, found no abnormalities. Check the fan, found that the silicone oil clutchoperation speed can not reach the normal running at high speed at high temperature, and sometimes appear lost phenomenon. In principle, the water temperature is so high, should not appear this phenomenon. Check the radiatoroutside also without clogging, consider that there may be silicone oil clutch failure.Check the radiator outside also without clogging, consider that there may besilicone oil clutch failure. Replacement test with replacement method, changing the last new silicone oil clutch test, the failure remains. It seems this fault is notcomposed of silicone oil fan clutch damage, the silicone oil fan why can not high speed?
The related repair data query Lexus 400 car, the silicone oil clutch in engine cooling water temperature gradually increased to 80-85 ℃, the radiator behind the air temperature was gradually increased to a certain temperature, the silicone oilclutch on the bimetal temperature deformation, clutch drive inside the valve platedeflection angles, the valve will the oil hole is opened, then, silicone oil from oilcavity flow chamber so as to drive the fan speed. Judge according to the working principle of silicon oil clutch, possibly through the temperature sensing element of the air temperature is low, unable to engage the clutch, or is in a critical state. Sothe multimeter to switch to the temperature measuring block, were detected in all parts of the radiator temperature thermocouple probe, found on both sides of thetemperature near the radiator, which is part of the middle part of silicone oil clutchtemperature was lower than that on both sides of the middle part of the water tank,can judge the clogging.
Because the user is not willing to replace the water tank, the cooling water tank todecompose descaling, open, found its internal on silicone oil clutch temperature sensing element, three Georgia channel blockage. After cleaning, loading andheavy load road repair long time trial, no abnormal phenomenon. Connect the tester from the data flow of coolant temperature readout in 80-90 ℃, air-conditioning outlet temperature in the 5 - 8 DEG C, thus, fault completely ruled out.
