If the thermostat is dismantled blindly because of the high temperature of the engine, the coolant can only carry on the large circulation, and the cooling strength can not be adjusted. It is difficult to ensure that the engine works at a more suitable temperature. Instead, the engine often works in the low temperature condition, which causes the engine power to fall, the wear loss is accelerated and the fuel consumption is increased. If the engine thermostat is troubleshooting or replaced, the engine temperature is still high, the other parts of the cooling system should be overhauled and the thermostat should not be removed. Some people think that when the engine is running, the temperature of the engine is not high. In fact, when the engine temperature is low, the danger is also great. The service life of the engine must be ensured according to the normal temperature required by the vehicle manual. The tighter belt is not the better. The tightness of the belt will not only lengthen or break the belt, shorten the life of the belt, but also cause the deformation and bending of the shaft of the generator and the shaft of the pump and the early damage of the bearing because of the excessive tension. The tightness of the automobile engine fan belt should meet the technical requirements. When the normal belt is assembled, the deflection is 10-15mm. When the speed is low, the oil pump can not press the lubricating oil into the lubricating surface quickly, and the oil pressure is low, so that the engine parts work under dry friction or semi dry friction, and the fuel oil is bad at low temperature and causes the unburned fuel (mixed gas) into the crankcase. Removing the oil film on the cylinder wall will also accelerate the wear of the machine parts. So, after the engine starts a few seconds, the application is fast idling heating (the modern car is equipped with a fast idle speed device, after the temperature rises, it will automatically adjust to the idle state) to improve the engine lubrication conditions. In winter, using a lamp to bake oil bottom will not only make chemical changes in the additives in the oil, but also lose the original performance, but also make the oil cemented and the oil bottom deformed and easily cause the fire. The best way is to choose suitable oil according to the local minimum temperature in winter. Where conditions permit, vehicles should be parked in the garage with thermal insulation facilities. The more advanced methods are ultrasonic cleaning and nuclear scavenging, but the most used and simplest methods are physical clearance and chemical cleaning. These two methods can also be used concurrently.