K3V63S Excavator Hitachi EX1200-6 EX1200-7 Fan Pump Auxiliary Cooling Piston Pump 4661674 4482892

The K3V63S fan pump is a variable displacement piston pump with an electronic regulator, designed for Hitachi EX1200-6 and EX1200-7 excavators. It drives the auxiliary cooling fan and automatically adjusts fan speed based on oil temperature, ensuring efficient thermal management in demanding mining and construction environments.

The pump is a variable piston design equipped with an electronic regulator. It drives the cooling fan and adjusts fan speed automatically according to oil temperature. Key components include:

• Cylinder block
• Pistons
• Slippers
• Valve plate
• Regulator
• Housing

1. Confirm the part number before ordering. Note that EX1200-5 and EX1200-6 are only partially interchangeable — verify compatibility prior to purchase.
2. For mining and heavy-duty applications, a genuine or high-quality aftermarket assembly is recommended.
3. If the housing is undamaged, repair using a piston, valve plate, and seal kit.
4. Strict oil cleanliness is required. Replace filters during installation.
5. Upon receipt, inspect the housing and seals, and confirm smooth shaft rotation.

1. Fan does not rotate or runs slowly, causing poor cooling and high water temperature.
2. Uncontrolled fan speed — the fan runs at full speed continuously.
3. Abnormal pump noise and vibration.
4. External oil leakage.
5. Internal wear leading to insufficient pressure.