1. check after engine start: open the refueling cover of radiator. if the cooling water in the radiator is calm, it means that the thermostat works properly; otherwise, it means that the thermostat does not work properly.
2. this is because when the water temperature is below 70, the expansion cylinder of the thermostat is in the contracting state and the main valve closes; when the water temperature is above 80, the expansion cylinder expands, the main valve opens gradually, and the circulating water in the radiator begins to flow.
3. when the temperature indicated by the thermometer is below 70, if the radiator enters the pipeline with water flow and the temperature is warmer, the main valve of the thermostat is not closed strictly, which makes the cooling water circulate prematurely.
4. check after the water temperature rises: the initial water temperature of the engine is over 1000 yuan. when the thermometer shows 80, the speed of temperature rise slows down, indicating that the thermostat works normally. conversely, if the water temperature has been rising rapidly, when the internal pressure reaches a certain level, the boiling water suddenly overflows, indicating that the main valve is stuck and suddenly opened.
5. when the thermometer indicates 70-80, open the radiator cover and the radiator drain switch to handle the water temperature. if the temperature is very high, the thermostat will work normally. if the inlet water temperature of the radiator is low, there is no water flow out or very little water flow out of the inlet pipe of the upper chamber of the radiator, the main valve of the thermostat can not be opened.
pump is the power of continuous circulation of cooling water in the cooling system. the factors affecting the pump are impeller and belt. the loosened impeller can not circulate cooling water, causing damage to the pump. the belt is too large, resulting in high water temperature, too small will cause damage to pump bearings, generator bearings.
fan air volume test: a sheet of paper can be placed in front of the radiator. when the engine runs, if you can blow paper, the air volume is enough. this is different from a car fan whose front engine sucks in air. blades can not be installed backwards, fan release cover should be complete and effective.
radiator, forklift chassis is low, radiator is located in the rear of the vehicle. the surface of radiator is easy to accumulate dust. if it is not cleaned up in time, it will seriously affect the heat dissipation effect. it is strictly forbidden to use "hard water" in cooling water to prevent scaling of radiator, which leads to insufficient cooling water.