Description
Komatsu’s catalogue entry for 708-1T-00580 gives the item name Pump Assembly and nothing more specific about the circuit. Trade listings attach it to the PC490-10 cooling fan, and the 708-1T prefix is consistent with the fan pumps we list elsewhere in this section. We state that split openly: the type is manufacturer-confirmed, the function is trade-established.
Applicability
Komatsu PC490-10 excavator. Suppliers also list the number against other -10 series machines; those applications are not confirmed by Komatsu data and we do not publish them as fact. Send the plate number from your old pump and the machine serial prefix and we will check before quoting.
Excavator duty differs from dozer duty, and it changes the failure
A dozer loads the converter continuously and runs the fan at high demand for long stretches. A 50 tonne excavator swings between a heavy digging cycle and long idle periods with the hydraulics unloaded, and on the -10 generation the fan speed is managed electronically against coolant and hydraulic oil temperature. Two consequences:
- The command path is part of the diagnosis. A proportional solenoid or a sensor fault holds the pump at part stroke, and a new pump changes nothing.
- Swing-idle heat soak is real. Oil temperature climbs during the idle phase when airflow demand has already fallen, which is why excavator fan faults often show as a high oil temperature alarm rather than as visible fan slowness.
Test in order: fault codes and command signal, then pump output pressure and flow hot, then fan motor case drain. The procedures are in our hydraulic fan pump diagnosis guide and regulator diagnosis and adjustment article.
Fitting
Match shaft spline, pilot, flange, port positions and control orientation against the removed pump. Prime the casing with clean oil before cranking. Change the return filter element and clear the suction strainer, targeting ISO 4406 18/16/13. Keep the case drain unrestricted to tank. Then prove the fan accelerates through its full range under thermal demand before the machine returns to work.
Ordering
Minimum order one piece. Three to six month warranty on new aftermarket units as stated on your proforma invoice. Bench checked and photographed against your order before the wooden case closes, delivery 5 to 8 working days from payment subject to stock. The PC800-8 fan pump is 708-1W-00901; the range sits under Komatsu hydraulic fan motor.
