main reason:
1. Insufficient air volume
2. The coolant is insufficient or does not meet the standard
3. The oil level is abnormal
4. Use inferior fuel
5. Thermostat failure
Diagnostic process of poor pump operation:
First step: Check to see if the Hitachi excavator engine is hot due to prolonged overloading or excessive ambient temperature.
The second step: check whether the coolant level is normal, and refill if less.
Step 3: Check if the fan belt is slipping, adjust if loose, clean if there is oil stain, and replace with new belt if necessary; check if the fan blade is deformed or damaged, and replace if deformed or damaged; check whether the air deflector is damaged or improperly positioned If it is improper, adjust or replace it if damaged; check the surrounding sealing of the radiator. If the seal is poor, you need to strengthen the seal; check whether the radiator ribs are blocked by debris, resulting in poor ventilation, and clean it.
The fourth step: check whether the oil level is in the specified position and not in the specified position, then fill or release the oil 4 to the specified position.
The fifth step: understand whether the user has been using antifreeze or soft water that meets the requirements. If so, the water tank and water channel need to be cleaned, and the damaged parts should be replaced when serious.
The sixth step: check whether the fuel quality meets the standard. If not, clean the fuel tank, oil passage, oil-water separator, and replace the fuel filter and fuel.
The seventh step: check whether the thermostat is working normally, and replace it normally.
Step 8: Check whether the pump works normally and replace it abnormally.
