2000 LEXUS GS400 cooling

I03741
2 1
3
4
AC0XN±01
Z13470
Magnetic Clutch Control
Low Pressure Side
ON (Continuity)
181 kpa
(1.85 kgf´cm
2, 28 psi)
OFF (No Continuity)High Pressure Side
3,140 kpa
(32.0 kgf´cm2, 455 psi)
OFF (No Continuity)
Z13471
Cooling Fan Control
ON1,520 kpa
(15.5 kgf´cm
2, 220 psi)
(No Continuity) (Continuity)
OFF
1,230 kpa
(12.5 kgf´cm
2, 178 psi) AC±76
± AIR CONDITIONINGPRESSURE SWITCH
2761 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
PRESSURE SWITCH
ON±VEHICLE INSPECTION
1. SET ON MANIFOLD GAUGE SET
(See page AC±17)
2. DISCONNECT CONNECTOR FROM PRESSURE
SWITCH
3. RUN ENGINE AT APPROX. 1,500 RPM
4. Magnetic Clutch Control:
INSPECT PRESSURE SWITCH OPERATION
(a) Connect the positive (+) lead from the ohmmeter to termi-
nal 4 and the negative (±) lead to terminal 1.
(b) Check continuity between terminals when refrigerant
pressure is changed, as shown in the illustration.
If operation is not as specified, replace the pressure switch.
5. Cooling Fan Control:
INSPECT PRESSURE SWITCH OPERATION
(a) Connect the positive (+) lead from the ohmmeter to termi-
nal 2 and the negative (±) lead to terminal 3.
(b) Check continuity between terminals when refrigerant
pressure is changed, as shown in the illustration.
If operation is not as specified, replace the pressure switch.
6. STOP ENGINE AND SET OFF MANIFOLD GAUGE SET
7. CONNECT CONNECTOR TO PRESSURE SWITCH

Z19533
32 1
541
43 2
5AC0XQ±01
I050271 2
5
1235
3
N23635
3
2
15
4
± AIR CONDITIONINGRELAY
AC±79
2764 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
RELAY
INSPECTION
1. INSPECT HEATER MAIN RELAY
(Marking: HTR) CONTINUITY
ConditionTester connectionSpecified condition
Constant2 ± 4
1 ± 3Continuity
Apply B+ between
terminals 1 and 3.5 ± 4Continuity
If continuity is not as specified, replace the relay.
2. INSPECT MAGNETIC CLUTCH RELAY
(Marking: A/C COMP) CONTINUITY
ConditionTester connectionSpecified condition
Constant1 ± 2Continuity
Apply B+ between
terminals 1 and 2.3 ± 5Continuity
If continuity is not as specified, replace the relay.
3. INSPECT No.2 COOLING FAN RELAY
(Marking: FAN NO.2) CONTINUITY
ConditionTester connectionSpecified condition
Constant1 ± 2
3 ± 4Continuity
Apply B+ between
terminals 1 and 2.3 ± 5Continuity
If continuity is not as specified, replace the relay.
4. INSPECT No.3 COOLING FAN RELAY
(Marking: FAN NO.3) CONTINUITY
Check the relay in the same way as for ºMAGNETIC CLUTCH
RELAYº.

AC0Y2±01
I03743
1 2 AC±80
± AIR CONDITIONINGCONDENSER FAN
2765 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
CONDENSER FAN
ON±VEHICLE INSPECTION
1. INSPECT CONDENSER FAN OPERATION
Inspect the fan operation, as shown in the chart below.
Test conditions:

Ignition switch ON

Blower speed control switch position ºHIº

Temperature control dial at ºMAX. COOLº

Install manifold gauge setº

A/C switch ON
ConditionFan operation (Fan speed)
Engine coolant temperature
91°C (196 °F) or belowRotate (Low speed)
Engine coolant temperature
100°C (212 °F) or aboveRotate (High speed)
Refrigerant pressure is less than
1,520 kPa (15.5 kgf´cm2, 220 psi)Rotate (Low speed)
Refrigerant pressure is 1,520 kPa
(15.5 kgf´cm2, 220 psi) or aboveRotate (High speed)
If operation is not as specified, proceed to the next inspection.
2. INSPECT CONDENSER FAN MOTOR OPERATION
(a) Disconnect the fan connector.
(b) Connect the positive (+) lead from the battery to terminal
2 and negative (±) lead to terminal 1 then check that motor
operations smoothly.

If operation is not as specified, replace the fan mo-
tor.

If operation is as specified, check the pressure
switch, cooling fan relays and engine coolant temp.
switch.

AC0Y3±01
I04719
Air Cleaner AssemblyRadiator Reservoir
Tank Cap
Cooling Fan Assembly
Air Cleaner
DuctUpper Radiator Hose
Reservoir Hose
Fan Motor
Fan Motor
Fan Shroud
Fan
Fan
± AIR CONDITIONINGCONDENSER FAN
AC±81
2766 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
COMPONENTS

AC0Y4±01
AC±82
± AIR CONDITIONINGCONDENSER FAN
2767 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
REMOVAL
1. DRAIN ENGINE COOLANT FROM RADIATOR
HINT:
It is not necessary to drain out all coolant.
2. REMOVE THESE PARTS:
(a) Air cleaner duct
(b) Air cleaner assembly
(c) Radiator reservoir tank cap
3. DISCONNECT THESE PARTS:
(a) Upper radiator hose
(b) Reservoir hose
4. REMOVE COOLING FAN
(a) Disconnect the connectors.
(b) Remove the 6 bolts cooling fan.

AC0Y5±01
± AIR CONDITIONINGCONDENSER FAN
AC±83
2768 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
DISASSEMBLY
1. REMOVE COOLING FANS
Remove the 2 nuts and both fans.
2. REMOVE COOLING FAN MOTORS
(a) Disconnect wire harness clamps.
(b) Remove the 6 screws and both motors.

D01047
Q03721
D01048
Q06925
AT±30
± AUTOMATIC TRANSMISSIONAUTOMATIC TRANSMISSION UNIT (2JZ±GE)
1978 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
12. REMOVE TORQUE CONVERTER CLUTCH MOUNT-
ING BOLT
(a) Remove the hole plug.
(b) Turn the crankshaft to gain access to each bolt.
(c) Hold the crankshaft pulley nut with a wrench and remove
the 6 bolts.
Torque: 48 N´m (490 kgf´cm, 35 ft´lbf)
HINT:
At the time of installation, please refer to the following item.
First install black colored bolt and then the 5 other bolts.
13. SUPPORT TRANSMISSION WITH JACK
14. REMOVE 4 ENGINE REAR MOUNTING SET BOLTS
Torque: 26 N´m (270 kgf´cm, 20 ft´lbf)
15. DISCONNECT CONNECTORS AND WIRE HARNESS
(a) Tilt down the transmission.
NOTICE:
Take care so that the cooling fan does not come in contact
with the fan shroud.
(b) Disconnect the following connectors:
(1) O/D direct clutch speed sensor connector
(2) Vehicle speed sensor connector
(3) Park/neutral position switch connector
(4) Solenoid connector
(c) Disconnect the wire harness from the clamp on the trans-
mission.

D01005
Q03721
D01048
Q06925
AT±36
± AUTOMATIC TRANSMISSIONAUTOMATIC TRANSMISSION UNIT (1UZ±FE)
1984 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
(b) Turn the crankshaft to gain access to each bolt.
(c) Hold the crankshaft pulley nut with a wrench and remove
the 6 bolts.
Torque: 48 N´m (490 kgf´cm, 35 ft´lbf)
HINT:
At the time of installation, please refer to the following item.
First install the black colored bolt and then the 5 other bolts.
12. SUPPORT TRANSMISSION WITH JACK
13. REMOVE 4 ENGINE REAR MOUNTING SET BOLTS
Torque: 26 N´m (270 kgf´cm, 20 ft´lbf)
14. DISCONNECT CONNECTORS AND WIRE HARNESS
(a) Tilt down the transmission.
NOTICE:
Take care so that the cooling fan does not come in contact
with the fan shroud.
(b) Disconnect the following connectors:
(1) O/D direct clutch speed sensor connector
(2) Vehicle speed sensor connector
(3) Park/neutral position switch connector
(4) Solenoid connector
(c) Disconnect the wire harness from the clamp on the trans-
mission.