Procedure for Engine Cooling Fan Circuit Test
1.Make sure hydraulic oil is at normal operating tem- perature by operating the machine for approximately 10 minutes. Make sure the hydraulic tank is full.
2.Park machine on a level surface with the cutting decks lowered and off. Make sure engine is off and the parking brake is applied. Raise and support hood.
CAUTION
Prevent personal injury and/or damage to equip- ment. Read all WARNINGS, CAUTIONS and Pre- cautions for Hydraulic Testing at the beginning of this section.
3.Raise seat to gain access to cooling fan circuit test port at the fan drive manifold (Fig. 44). Connect a 5,000 PSI (345 bar) gauge with hydraulic hose attached to test port on top of manifold.
4.Start the engine. Move throttle to full speed (2870 RPM).
5.While monitoring the pressure gauge and using a phototac to identify the cooling fan speed, disconnect the wire harness connector (white/green and black wires) from the PRV solenoid on fan drive manifold. Both fan speed and pressure should increase and stabilize after the solenoid is disconnected.
PRESSURE GAUGE READING TO BE approxi- mately 3000 PSI (207 bar).
PHOTOTAC READING TO BE: fan speed approxi- mately 2800 RPM.
6.Stop engine and record test results.
7.If pressure rises to approximately 3000 PSI (207 bar) but fan speed is low, consider that the fan motor is worn or damaged. If pressure and fan speed are both low, consider that the gear pump is worn or damaged (see Engine Cooling Circuit Gear Pump Flow Test).
NOTE: If pressure and fan speed are both low and gear pump flow proves to be correct, suspect that seals in fan drive manifold are leaking or faulty (see Fan Drive Man- ifold Service in the Service and Repairs section of this chapter).
8.When testing is complete, remove pressure gauge and reconnect wire harness to PRV solenoid.
3 |
2 |
1 |
Figure 44
1. | Fan drive manifold | 3. Test port |
2. | PRV solenoid |
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System
Hydraulic
Groundsmaster | Page 4 | Hydraulic System |
