A driving range of about 40000 km, models E84, engine type of N46 2013 BMW X1 sport-utility vehicle, there are a lot of friends reflect the car speeding coolant temperature warning light alarm, need to use Auto Diagnostic Tool detection.
Maintenance personnel to check the expansion tank in the cooling fluid is missing, there have cooling liquid leakage traces, doubt cooling system has a leak, the system for pressurized testing, good sealing.
Detecting an engine control unit, found no fault record on coolant temperature. Use the Launch X431 GDS or Launch X431 V Pro tool control cooling fan operation, to determine the fan work normal. N46 type engine water pump is a mechanical driver, as long as the engine running it will work. So will check of the opening of the emphasis on thermostat, cooling system, circulation and cooling system on the gas resistance.
In view of the vehicle mileage is not much, so doubt any wind resistance in the cooling system, cooling fluid according to standard process of adding and steam. And adjust the liquid level to the standard position. Road test, the test member come back soon, reflect the coolant temperature is high, and connect the thermostat pipe is cold. Read the circuit diagram, see the thermostat controlled by the engine control unit. In fault diagnosis instrument to observe the thermostat signal waveform, compared with the normal car found waveform, show that no control problems. Doubt thermostat has a problem, replace the thermostat test, fault is still.
After just tried to touch his hand car radiator, we found the upper and lower temperature difference, indicating that the coolant is not flowing from the interior, replace the radiator test, fault still exists. Promote the flow of the coolant pump, use Autel MaxiSys MS908 or Autel MaxiScan JP701 tool to check the pump, the pump impeller was found not rotated. Remove the water pump turned by hand, found stuck, replace the water pump test, troubleshooting.