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 .