Common Faults Insufficient output flow of the fan pump, low fan speed, and engine overheating. Low pressure of the auxiliary pump and slow response of pilot control. Abnormal noise during pump operation accompanied by housing vibration. Oil leakage at the pump mating surface and shaft end, damaged oil seals and gaskets. Wear of internal gears and flow distribution components, leading to pump overheating. Severe pressure fluctuation and unstable fan speed. Purchasing