Descrizione
On a 29 tonne Volvo excavator the fan drive is a gear pump, which is good news for reliability and bad news for subtlety. A gear pump has no regulator to blame and no control to adjust. It delivers a volume proportional to engine speed, minus whatever it is leaking internally. When it wears, the loss is direct and measurable.
Applicabilità e prove
Volvo EC290B excavator. Volvo’s parts catalogue lists the item name as Gear Pump, and dealer parts data describes its role as supplying the hydraulic cooling circuit that drives the fan. Volvo does not publish a displacement, pressure or flow figure for this number, so none is quoted here; confirm against the plate on your pump.
What a fan pump does on a Volvo excavator
Volvo’s published description of its loader cooling system applies to the principle behind this component: the fan is hydraulically driven, it regulates component temperature, and on current machines it can be automatically reversed to self-clean the cooling units. On an excavator the same idea appears as a fan pump feeding a fan motor, and the pair is the only thing standing between a hot day and a derated machine.
Three things kill these pumps, and none of them is the pump’s own design:
- Contamination. Gear tips and side plates score easily, and the fan circuit is usually the last place a workshop thinks to flush.
- Heat. A machine already running hot thins the oil, which increases internal leakage, which reduces airflow, which increases heat. It is a loop, and it accelerates.
- Starvation. A blocked suction strainer or a collapsed hose liner makes a healthy pump noise, wear, and then fail, and the replacement inherits the same restriction unless it is cleared.
Diagnosis order before you order a pump
- Clean the radiator and oil cooler cores, then re-measure temperatures at low and high idle.
- Confirm the fan motor turns freely with the hoses disconnected.
- Measure pump outlet flow and pressure at working temperature.
- Check the suction line, the tank filter and the oil level.
- Only then replace the pump, and change the filter element as part of the job.
The written procedures are in our guida alla diagnosi della pompa idraulica del ventilatore, e il lato motore è trattato in la guida alla diagnosi del motore del ventilatore.
Montaggio e ordinazione
Match shaft spline or taper, pilot diameter, flange bolt pattern, port positions and rotation direction against the removed pump; gear pumps are direction-sensitive and a reversed unit will destroy itself on first start. Prime with clean oil before cranking, change the return filter element, and target ISO 4406 18/16/13 for the piston components sharing the circuit. 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 EC330B and EC360 fan pumps are listed alongside this page under Volvo hydraulic fan motor.
