Fan not rotating / abnormal speed:
Measure the fan motor inlet pressure and flow. If pressure is normal but the fan does not turn, it indicates internal motor wear. If pressure or flow is insufficient, check the fan pump, filter, and oil circuit.
Variable-speed failure (constant high/low speed):
Faulty solenoid valve or abnormal electronic control signal. This unit has an electronically controlled variable-speed fan; check the solenoid and wiring first.
Abnormal noise / squealing:
Worn motor bearing, air ingestion in the system (cavitation), or contaminated oil.
Oil leakage:
Aged shaft oil seal or worn end-cover O-rings.
High oil temperature:
Severe internal motor leakage generates heat, accelerating wear.
Repair & Purchasing Recommendations
Light wear:
Replace the oil seal and seal kit, clean the interior, and inspect or repair the solenoid valve.
Severe scoring:
Replace the rotating group parts or the fan motor assembly.
After reassembly, always fill with hydraulic oil before starting. Running dry will burn out the motor.
When ordering, confirm the specific sub-model and the original old part number.