1 Failure phenomenon
Engine water temperature is high.
2 points of failure
· Insufficient coolant
· The coolant is not replaced in time and deteriorates, causing poor heat dissipation or blocking the water channel
· Too little oil
· Insufficient cooling air volume
· Fan blade deformation
Deformed or blocked internal radiator fins
· The radiator air duct is blocked
Water temperature sensor or circuit failure
The thermostat cannot open the large cycle
· The pump is not working well
· Ignition time of the engine is not correct, the afterburning period is too long
Engine cylinder head is damaged
Cracks in the engine block or head
3 troubleshooting ideas
3.1 Check the coolant level. If the coolant is too little, add it; otherwise, go to the next step.
3.2 Check the coolant for deterioration. If it deteriorates, replace the antifreeze after cleaning the water course; otherwise, go to the next step.
3.3 Check the engine oil level. If the oil is too little, add or replace it; otherwise, go to the next step.
3.4 Check whether the water radiator is blocked by foreign objects and whether the radiator air duct is blocked. If blocked, clean up; otherwise, go to the next step.
3.5 Check if the fan blade is deformed and the air volume is too small. If yes, replace the fan or adjust the belt; otherwise go to the next step.
3.6 Check the water temperature sensor and circuit for short circuit or open circuit. If yes, proceed; otherwise go to the next step.
3.7 Disassemble and inspect the thermostat and put it in hot water to observe the opening of the thermostat. If not, replace the thermostat; otherwise go to the next step.
3.8 Replace the water pump. If the fault is not rectified, go to the next step.
3.9 Adjust the injection timing. If the fault is not rectified, go to the next step.
3.10 Check the cylinder block and cylinder head for cracks and damage.
4 Failure cases
4.1 Case information
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4.2 Case Phenomenon
Engine water temperature is high and antifreeze needs to be added frequently.
4.3 Processing steps and results
4.3.1 After the machine works for 20 minutes, check that the water temperature is 101 degrees.
4.3.2 Continue to work for 5 minutes, the engine water temperature alarm. The engine runs at idle speed and stops after the water temperature drops. After filling the antifreeze, start the machine, observe the expansion water tank, and find that there are a lot of air bubbles. After increasing the throttle, the antifreeze channeled from the expansion water tank mouth.
4.3.3 Check the oil level gauge and find that the oil level rises and the oil becomes thinner.
4.3.4 The engine was disassembled and inspected, and the three-cylinder gasket of the engine was found to be damaged.
4.3.5 The engine three-cylinder gasket was damaged, which caused antifreeze to enter the three-cylinder, and white smoke was emitted when starting. During engine operation, the high-pressure gas in the cylinder penetrates into the cooling system through the damaged part of the cylinder pad, causing a large number of bubbles, and the high-temperature and high-pressure gas penetrates into the antifreeze, which causes the temperature of the antifreeze to rise rapidly. After shutdown, the antifreeze fluid will enter the cylinder along the damaged part of the cylinder pad and enter the oil pan, causing the oil level to rise.
4.3.6 Replace the cylinder pad, and troubleshoot.