the problem is in the system design. the location of fan sensor is wrong so it must not be over the motor heads but it must be at the radiator. the easiest way to solve the problem by removing the thermostat from its original place and put a new one at the water exit pipe from the engine, you may use thermostat that used inside tube like renult 5 thermostat. then the system will work correct. the problem is because the thermostat located between the engine and the radiator so one side hot and one side cold, and as the cold water pass the thermostat it will not open as required to cycle water and the engine will remain hot and the fan heat sensor will ask the fan to work while the water in radiator is cold and this will make the water goes to thermostat colder and make it to more close while the hot water trapped inside engine as it is very hot and no water cycle. if we change the place of thermostat to water exist side from engine, then both sides of thermostat will have hot water and will not close until the all water in the system become cold and the water cycle will be perfect and the engine wont become with excess heat. so it is design mistake.
