Toro Groundsmaster 4500-D Service Manual page 109

Procedure for Engine Cooling Fan Circuit Test
The engine cooling fan circuit test should be performed
to make sure that the engine cooling fan circuit has the
correct system pressure and fan speed.
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.
1. Make sure hydraulic oil is at normal operating tem-
perature by operating the machine for approximately ten
(10) minutes. Make sure the hydraulic reservoir 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.
3. Raise and support hood to gain access to fan control
manifold (Fig. 56). Connect a 5,000 PSI (345 bar) gauge
with hydraulic hose attached to test fitting in port G1 on
rear of manifold.
4. Start the engine and increase engine speed to high
idle speed.
5. While monitoring the pressure gauge and using a
phototac to identify the cooling fan speed, disconnect
the wire harness connector (white/violet and black
wires) from the proportional relief valve solenoid at fan
control manifold (port TS). Both fan speed and pressure
should increase and stabilize after the solenoid is dis-
connected.
PRESSURE GAUGE READING TO BE approxi-
mately 3000 PSI (207 bar)
PHOTOTAC (fan speed) READING TO BE approxi-
mately 2800 RPM
6. Stop engine and record test results.
Groundsmaster 4500--D/4700--D
7. If pressure rises to approximately 3000 PSI (207
bar) but fan speed is low, consider that the hydraulic fan
motor is worn or damaged. If pressure and fan speed
are both low, consider that final gear pump section is
worn or damaged (see Gear Pump Flow Test in this sec-
tion).
NOTE: If pressure and fan speed are both low and the
final gear pump section flow proves to be correct (see
Gear Pump Flow Test in this section), suspect that seals
in fan control manifold are leaking or faulty (see Fan
Control Manifold Service in the Service and Repairs
section of this chapter) or that fan motor is worn or dam-
aged.
8. When testing is complete, remove pressure gauge
from manifold fitting and reconnect wire harness to pro-
portional relief valve solenoid. Lower and secure hood.
1. Fan control manifold
2. Test fitting (port G1)
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3
2
Figure 56
3. PRV solenoid
Hydraulic System
1