The engine overheats. Generally speaking, the cooling water temperature in the engine block is too high. There are two common causes of overheating of excavator engine, namely, the decline of heat dissipation capacity and excessive heat load. Poor heat dissipation is one of the reasons for the decline of heat dissipation capacity. The reasons for poor heat dissipation of excavator are as follows:
① Influence of radiator after the radiator has been used for a long time, the scale inside the radiator is thickened accordingly. Due to the poor heat transfer capacity of scale, the heat dissipation will be poor.
② The radiator vent is blocked. When the engine is working, the dust will flow through the radiator with the air due to the action of the fan. When dust adheres to the flat tubes and fins of the radiator, it not only reduces the air circulation section of the radiator, but also causes poor heat dissipation due to poor thermal conductivity due to dust and dirt.
③ The cooling intensity of the fan belt slipping water cooling system depends on the fan speed. If the fan drive belt slips due to too loose, it will reduce the power transmission efficiency, which will not only reduce the fan speed and cooling intensity, but also reduce the water pump speed and displacement, so that the cooling water flows slowly and can not take away the heat quickly, that is, poor heat dissipation.
④ Influence of cooling intensity regulating device louvers and thermostats are cooling intensity regulating devices. If the cooling intensity regulating device fails or operates improperly, the engine temperature will be too high. The louver is set in front of the radiator to adjust the ventilation flow of the radiator. When the opening is large, the ventilation volume is large, otherwise when the opening is small. When the shutter is not opened, the flow section of the cooling air is smaller, resulting in an increase in the engine temperature.
⑤ The thermostat is set at the water outlet of the engine to adjust the cooling intensity, that is, when the engine temperature is low, cut off the large circulating water circuit and connect the small circulating water circuit to reduce the heat dissipation and increase the engine temperature quickly; When the engine temperature rises to the specified temperature, the thermostat will connect the large circulating water circuit and close the small circulating water circuit. If the thermostat is damaged, the large circulating water circuit cannot be connected, resulting in poor cooling water circulation, so that the heat absorbed by the cooling water cannot be brought to the radiator and the engine overheats.
⑥ When the cooling water works in winter, the cooling water temperature in the radiator lower chamber is very low and easy to freeze. After freezing, the cooling water will not circulate, resulting in excessive cooling water temperature.
