1991 LEXUS SC300 cooling system

ASSEMBLY OF HYDRAULIC MOTOR
(See Components on page CO±50)
HINT:
w Thoroughly clean all parts to be assembled.
w Before installing the parts, apply new fluid to all sliding
and rotating surfaces.
1. MOUNT MOTOR HOUSING Slightly mount the motor housing in a vise.
NOTICE: Be careful not to damage the motor housing.
2. INSTALL FRONT THRUST WASHER
3. INSTALL DRIVEN AND DRIVE ROTORS Install the d rive and driven rotors with the dot mark facing up-
ward.
4. INSTALL DRIVE SHAFT
5. INSTALL REAR THRUST WASHER
6. INSTALL MOTOR COVER (a) Install a new O±ring to the motor housing groove.
(b) Install the motor cover with the four bolts.
Torque: 28 N Vm (290 kgf Vcm, 21 ft Vlbf)
CO±54±
COOLIING SYSTEM Electronically Controlled Hydraulic Cooling Fan
(Hydraulic Motor)
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7. INSTALL DRIVE SHAFT PRELOAD(a) Check that the drive shaft rotates smoothly withoutabnormal noise.
(b) Temporarily install the pulley nut, and check the rotating
torque.
Rotating torque:
0.3 N Vm (3.0 kgf Vcm, 2.6 in. Vlbf)
INSTALLATION OF HYDRAULIC MOTOR
(See Components on page CO±47)
1. INSTALL HYDRAULIC MOTOR TO FAN SHROULD Install the hydraulic motor with the three bolts.
Torque: 4.9 N Vm (50 kgf Vcm, 43 in. Vlbf)
2. INSTALL COOLING FAN TO HYDRAULIC MOTOR
Install the fan with the plate washer bolt.
Tighten the nut by turning it counterclockwise.
Torque: 15 N Vm (150 kgf Vcm, 11 ft Vlbf)
3. INSTALL RADIATOR FAN SHROULD
(a) Place the fan shrould on the radiator.
(b) Slightly lift the fan shrould, and connect the two oil cooler
hoses (for cooling fan) to the hose clamp on the fan
shrould.
(c) Install the fan shrould with the four bolts.
Torque: 4.9 N Vm (50 kgf Vcm, 43 in. Vlbf)
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COOLIING SYSTEM Electronically Controlled Hydraulic Cooling Fan
(Hydraulic Motor)CO±55
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(d) Install the wire clamp to the fan shrould.
4. INSTALL COOLING FAN RESERVOIR TANK TO FAN SHROULD
(a) Install the reservoir tank with the four bolts.
Torque: 4.9 N Vm (50 kgf Vcm, 43 in. Vlbf)
(b) Install the suction hose to the clamp on the fan shrould.
5. INSTALL COOLING FAN INLET PIPE TO FAN SHROULD Install the inlet pipe with the two bushings, brackets and
bolts.
Torque: 4.9 N Vm (50 kgf Vcm, 43 in. Vlbf)
6. CONNECT HOSES
Connect the following hoses:(1) Pressure hose to hydraulic motor C onnect the
pressure hose with a new gasket and union bolt.
Torque: 64 N Vm (650 kgf Vcm, 47 ft Vlbf)
(2) Return hose to hydraulic motor.
(3) Upper radiator hose to radiator.
CO±56
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COOLIING SYSTEM Electronically Controlled Hydraulic Cooling Fan
(Hydraulic Motor)
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7. INSTALL RADIATOR RESERVOIR TANK(a) Install the reservoir tank to the reservoir tank bracket.
(b) Install the reservoir tank bracket with two bolts.
Torque: 4.9 N Vm (50 kgf Vcm, 43 in. Vlbf)
(c) Connect the following hoses:
(1) Reservoir hose to water inlet housing
(2) Reservoir hose to radiator
(d) Connect the coolant level sensor connector.
8. INSTALL BATTERY
9. FILL ENGINE WITH COOLANT (See page CO±7)
10. FILL COOLING FAN RESERVOIR TANK WITH FLUID
(See pages CO±23 and 24)
11. START ENGINE AND CHECK FOR LEAKS
12. INSTALL ENGINE UNDER COVER
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COOLIING SYSTEM Electronically Controlled Hydraulic Cooling Fan
(Hydraulic Motor)CO±57
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Oil Cooler
COMPONENTS FOR REMOVAL AND
INSTALLATION
REMOVAL OF OIL COOLER
1. REMOVE FENDER LINER
2. DISCONNECT PS OIL COOLERRemove the two bolts, and disconnect the PS oil cooler from
cooling fan oil cooler.
3. DISCONNECT HOSES FROM OIL COOLER Disconnect the following hoses:(1) Inlet hose (from reservoir tank)
(2) Outlet hose (from hydraulic motor)
CO±58
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COOLIING SYSTEM Electronically Controlled Hydraulic
Cooling Fan (Oil Cooler)
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4. REMOVE OIL COOLERRemove the three bolts and oil cooler.
INSPECTION OF OIL COOLER
INSPECT OIL COOLER
Check the oil cooler for damage or clogging.
If necessary, replace the oil cooler.
INSTALLATION OF OIL COOLER
(See Components on page CO±58)
1. INSTALL OIL COOLER Install the oil cooler with the three bolts.
Torque: 18 N Vm (180 kgf Vcm, 13 ft Vlbf)
2. CONNECT HOSES FROM OIL COOLER
Connect the following hoses:(1) Inlet hose (from reservoir tank)
(2) Outlet hose (from hydraulic motor)
3. INSTALL PS OIL COOLER Install the oil cooler with the two bolts.
4. REMOVE FENDER LINER
5. FILL COOLING FAN RESERVOIR TANK WITH FLUID
(See pages CO±23 and 24)
6. START ENGINE AND CHECK FOR LEAKS
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COOLIING SYSTEM Electronically Controlled Hydraulic
Cooling Fan (Oil Cooler)CO±59
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Electronic Control Parts
(System Circuit)
(Cooling Fan ECU)
COMPONENTS FOR REMOVAL AND
INSTALLATION
CO±60±
COOLIING SYSTEM Electronically Controlled Hydraulic Cooling Fan
(Electronic Control Parts)
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INSPECTION OF COOLING FAN ECU
1. DISCONNECT CABLE FROM NEGATIVE TERMINAL OFBATTERY
CAUTION: Work must be started after 20 seconds or longer
from the time the ignition switch is turned to the ºLOCKº posi-
tion and the negative (±) terminal cable is disconnected from
the battery.
2. DISCONNECT COOLING FAN ECU CONNECTOR (See Components on page CO±60)
(a) Remove the instrument panel under cover.
(b) Remove the lower instrument panel finish panel and glove compartment door assembly.
(c) Disconnect the cooling fan ECU connector.
3. INSPECT COOLING FAN ECU (a) Connect the cable to the negative (±) terminal of thebattery.
(b) Check the connector on the wiring harness side as shown in the chart.
Check forTester connectionConditionSpecified value
Voltage1±GroundIgnition switch ONBattery voltage
Resistance2±3Solenoid valve at cold (20 5C (68 5F))7.5±8.5

Continuity4±Ground±Continuity
Continuity5±GroundThrottle valve openNo continuityContinuity5±GroundThrottle valve closedContinuity
Resistance9±10Coolant temp. at 80 5C (176 5F)1.48±1.58 k

(c) Disconnect the cable from the negative (±) terminal of
the battery.
4. RECONNECT COOLING FAN ECU CONNECTOR
5. RECONNECT CABLE TO NEGATIVE TERMINAL OF BATTERY
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COOLIING SYSTEM Electronically Controlled Hydraulic
Cooling Fan (Electronic Control Parts)CO±61
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