With the temperature rising gradually, many friends reported that the excavator had a headache for the excavator masters, that is, the hydraulic oil temperature was high; If the high temperature of hydraulic oil is not handled in time, the internal leakage of hydraulic pump, main control valve and various working devices will be achieved in the long run, and it must be repaired or replaced in serious cases.
A sk250-8 hydraulic excavator of Kobelco has been working for 8000 hours. Recently, the hydraulic oil temperature has been high. The hydraulic oil temperature can reach 80 ℃ after half an hour of operation. If it continues to work, the hydraulic oil temperature will keep rising until it gives an alarm.
Inspection analysis:
1. The pressure, flow and variable performance of the excavator hydraulic pump were tested to be normal, and no problems were found in the hydraulic oil tank and oil inlet pipeline.
2. When checking the hydraulic oil radiator, it was found that the wind force of the cooling fan was obviously weak. The fan is directly driven by a hydraulic motor whose hydraulic oil comes from the special hydraulic pump for cooling the front gear box of the engine.
3. Is there a problem with the cooling hydraulic pump or motor? We tested the pressure entering the fan drive motor. When the engine speed was 2000 rpm, the value was 148kg/cm2. From this, we concluded that the fan drive motor and the hydraulic pump were all OK. No obvious problems were found during the re inspection of the air duct.
4. The above inspection can preliminarily determine that there is a problem with the fan blade. However, the fan blades were expensive (at that time, the order unit price was 13000.00 yuan) and no replacement parts could be found. We further verified the judgment and measured the fan speed as 1990/ min. Therefore, it was concluded that there was a problem with the fan blade, and the hydraulic oil temperature returned to normal after ordering replacement.
The engine water temperature is too high. Let's talk about the problem of high engine water temperature. Incorrect ignition timing, insufficient engine power, and failure of the cooling system will cause the engine water temperature to be too high. On excavators equipped with common rail EFI diesel engines, since the hydraulic oil radiator is installed upstream of the cooling air of the water tank, overheating of the hydraulic oil will also cause excessive water temperature.
