In March, the temperature around the country began to rise, and many regions have entered the summer mode in advance. After the temperature rises, we should pay attention to whether the truck has a fever! Here, fever means that the engine temperature exceeds the maximum operating temperature range.
Analyzed from the main structure and heat dissipation principle of diesel engine cooling system, the main causes and troubleshooting methods are as follows:
1 Insufficient coolant
The heat of the engine is mainly taken away by the coolant and dissipated. If the coolant is reduced due to the leakage or evaporation of the water tank and water pipe, the heat naturally taken away will be reduced, and the accumulated heat in the engine will be too much, resulting in overheating of the engine.
Judgment and elimination methods
Check whether the water tank and external pipes have water leakage. If there is water leakage, it indicates that the overheating of the engine is caused by water leakage, and the water leakage should be eliminated in time. If there is no water leakage, open the radiator water filling cap and observe whether the cooling water is sufficient. Most of the reasons are that the engine is overheated due to not adding coolant for a long time, which should be supplemented in time.
2. The fan belt is too loose and slipping
The cooling intensity of the diesel engine depends on the fan speed. If the fan drive belt is too loose and slipping, it will inevitably cause the power transmission efficiency to drop, the fan speed will drop, the cooling intensity will drop, and the pump speed will also drop, and the displacement will be reduced, so that the cooling water flow speed will be reduced, and the heat cannot be taken away quickly, resulting in poor heat dissipation of the diesel engine.
Judgment and elimination methods
When the diesel engine stops working, move the fan blade by hand. If the fan can be moved to slip, it means that the fan belt is too loose and causes poor heat dissipation, which should be adjusted.
3. Thermostat failure
The thermostat is set at the water outlet of the engine. Its function is to regulate the cooling intensity. When the engine body temperature is low when the diesel engine is just started, it can effectively cut off the large circulating water circuit and automatically connect the small circulating water circuit, reducing the heat dissipation and making the temperature of the diesel engine rise quickly.
When the temperature of the diesel engine rises to a certain temperature after a period of operation, the thermostat will automatically open the large cycle and close the small cycle, and increase the heat dissipation to keep the water temperature of the diesel engine within a certain range.
If the thermostat is damaged and the large circulation water circuit cannot be connected, the coolant circulation will not be smooth, and the diesel engine will not heat well, which will cause overheating.
Inspection and troubleshooting methods:
Remove the thermostat, put it into hot water, and check whether the thermostat lift is normal.
4. Too much scale in cooling system
The engine that has been used for a long time is prone to the phenomenon that the scale on the cylinder block and radiator is too thick, resulting in poor heat dissipation.
Exclusion method:
Conduct chemical cleaning for the cylinder block and radiator. Common chemical cleaning solutions include 8% caustic soda solution, 10% sodium carbonate solution or 2.5% hydrochloric acid solution.
When using the first two cleaning solutions, keep the solution in the cooling system for 10-12 hours; When the third cleaning fluid is used, the engine should be started immediately after injection and run for 1 hour at low speed without load.
Why do Chinese made generator radiators have the highest cost-effectiveness?