A. The hydraulic system of the pump truck itself generates heat. The components such as the fuel tank will passively dissipate heat, while the radiator will actively dissipate heat. Under normal circumstances, the heat of the system will reach a balance. If the radiator fan's efficiency is not high or damaged, the heat-dissipating part will not work, which will cause the system oil temperature to be high, but in this case, the oil temperature will be higher than normal and will not continue to rise after reaching a value .
B. The system fails and continues to generate heat. The most important components that generate heat in the hydraulic system are the relief valve and other components with relief function.
C. After the hydraulic system of the pump truck is used for a long time, after the components are worn normally, the leakage will increase, and the temperature of the hydraulic system will be higher than that of the new system. In this case, the system temperature will be maintained at a high value, but will not continue to rise.
D. An external heat source heats the hydraulic system