发动机过热的诊断与排除（Diagnosis and removal of engine overheating）

发动机过热的诊断与排除（Diagnosis and removal of engine overheating） 发动机过热的诊断与排除(Diagnosis and removal of engine overheating) It is a kind of malignant engine overheating fault, it directly harms the engine work, serious when can cause the piston and the cylinder block or strain. So, once the engine overheating should according to its different forms for accurate diagnosis and timely remove. The use of a sudden overheating The car is in operation, the cooling system has been in good condition, if the engine suddenly overheating, the main reason has the following: 1, the cooling system caused serious leakage and insufficient coolant overheat. In this regard, can be directly observed through diagnosis and troubleshooting smoothly. 2, the cooling water circulation pump failures caused the engine to overheat interruption. This can be used for diagnosis of the symptoms of touch method, the specific performance of the engine temperature is very high, especially in the lower part of the radiator and the low temperature. In this regard, deal with the pump for the repair or replacement of water pump. 3, water pump belt broken and overheating. Careful maintenance personnel or the driver can know by observing the dynamic current meter, if driving instructions for charging or discharging light while the engine is overheating, it is the water pump belt broken. 4, the thermostat main valve off and stuck in the water inlet pipe, hinder cooling water circulation, so that the pressure in the engine water jacket rises rapidly, when the pressure reaches a certain level (high), the cooling water will urge the main valve to change the direction card lag, conduction cycle of water. At this time, the boiling water to the radiator cover great pressure impulse, the emergence of a strong "boil" phenomenon. This fault should replace the thermostat. The cooling water shortage and overheating The water shortage of cooling water has two main types: cooling water leakage or evaporation, water capacity is lower than the standard capacity. 1, in the operation of cooling water consumption excessive overheating. This should be checked according to the following methods: (1) will fill the water tank, engine idling, check radiator, water pump and cooling system of the drainage hole if there is leakage, if any should be excluded; (2) check whether there is water in the crankcase oil. If the oil in the water to the engine overhaul; (3) check whether the exhaust pipe drainage phenomenon. If possible, is a cylinder gasket destroyed, the water jacket and cylinder rigging. We should repair and replace cylinder pad. The water capacity of 2, lower than the standard cooling system capacity and overheating. Test method for: Too much scale (1). Mainly do the cooling liquid engine in the long water, as the mileage increases, scale, cooling water jacket wall in contact with the cooling water pipe will be gradually thickening, especially high temperature part. There is a layer of insulating material like radiating surface which makes the cooling system of the engine power, the heat generated is difficult to dispersed and overheating. The scale is too much, can choose the scale cleaning agent, in accordance with the operating instructions on the method to get rid of scale. (2) the water tank is clogged. There was a car CA1091 car, often overheating. The capacity check, found far lower than the standard capacity in removing the tank when the tank is found, the original water tank sludge, scale, cotton and other debris will be many, many core pipe plug, remove after repair, overheating phenomenon disappeared. Other causes of overheating The exclusion of the several factors that lead to the engine overheating after still can not solve the problem, you need to check whether there are several reasons. 1, the ignition timing. The engine is in use, with the extension of time, mechanical wear will gradually increase, the ignition time has a gradually late phenomenon, coupled with some car repair personnel always worry about the ignition will first appear detonation, during calibration often artificially delayed ignition time. Late ignition, combustion gas contact time and cylinder wall will be too long, will eventually lead to engine overheating. In addition, the ignition distributor in advance device working poor or failure, will cause the engine ignition too late. Therefore, regularly adjust ignition timing and ensure the ignition device is in good condition, to prevent overheating of the engine is very good. 2, the thermostat failure. Mainly for the thermostat main valve does not open or thermostat card lag between large and small circulation, in addition to the thermostat aging, poor sealing swollen body leakage etc.. These failures will affect the engine temperature cooling water circulation and engine overheating. The thermostat check has two kinds: one is to start the engine (in when the engine speed is constant), open the tank cover observation, if the same phenomenon in low temperature and high temperature rolling, as the thermostat was stuck in the big small cycle; if the low temperature, strong surface rolling is the thermostat in the card circulation; if the temperature reaches normal working temperature of the engine when the liquid level is still calm, that the thermostat can not be opened. The two is the thermostat placed in cold liquid heating, observe the opening temperature, temperature and open the main valve lift and other indicators are in accordance with the provisions. If there is any one index is not up to the requirements it should replace the thermostat. 3, fan clutch side. A silicone oil fan clutch should check the temperature at 90-95 degrees, the fan can achieve full speed. Simple method of detection is: flameout at high temperature, push the fan, feel laborious is normal; otherwise, the need for maintenance. The temperature control of electric fan to check, Santana as an example: under normal circumstances, when the temperature reaches 93-98, the fan started running at a low speed; when the temperature rises to 99-105 DEG C, fan start high-speed operation. Otherwise, should replace the temperature control switch. 4. The influence of combustion chamber of coke. The combustion chamber deposits too much, will make the engine burn, early, but also lead to poor heat. In this regard, should be timely removal of coke combustion chamber. 5, the hot season, big load long time operation. In this case, should pay attention to the coolant temperature changes, when necessary, should break through the shade, idle cooling. In addition, the car is equipped with air conditioning, air conditioning should also be shut down to prevent overheating. 6, air conditioner. Some car in the same parts of the original case, installation of air conditioning system, the heat load of condenser to radiator, caused the engine to overheat. In this regard, we should take the following measures: one is to increase the size of the fan or fan blade, the two is to adjust the position of the condenser, when necessary, the installation of electric fan, three is diligent maintenance, often clean the blockage between the fin radiator, condenser, improving the heat dissipation capacity. As for the frequent overheating of the engine. Should also pay attention to the following parts of the examination: one is the fan blade angle should meet the requirements; two is the fan blades are too few (mainly modified cars), fitted with a fan guard ring; three is a 492Q type gasoline engine should also check the front baffle cylinder cover water pump inlet and outlet are corrosion to four the car is sliding performance is good.