Page 15 of 1111
AC0WJ±01
I02365
Instrument Panel
Reinforcement
No.2 Brace
No.1 Brace
Water Hose
Bracket
Blower Unit Liquid Tube
Suction Hose
10 (100, 7)
Defroster Nozzle
Heater to Register
Center Duct
Air Duct
Air Duct RH
Center Air Duct
Air Duct LH
O±Ring
A/C Unit
N´m (kgf´cm, ft´lbf) : Specified torque
Non±reusable part
AC±22
± AIR CONDITIONINGAIR CONDITIONING UNIT
2707 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
AIR CONDITIONING UNIT
COMPONENTS
Page 16 of 1111
I02366
Wire Harness
Packing
Packing
Tube Connector
Evaporator Temperature
Sensor
Bracket Plate
Wire Harness
O±Ring O±Ring
Tube and Accessory
4.1 (42, 36)
4.1 (42, 36)
Expansion Valve
O±Ring
Evaporator
Plate
Insulator Air Mix Servomotor
(Driver Side)
Air Outlet Servomotor
Air Duct
Cover
Drain PipeDrain Hose Air Mix Servomotor
(Passenger Side)
Heater Radiator
Blower Motor
Control Relay
N´m (kgf´cm, in.´lbf) : Specified torque
Non±reusable part
Packing
Air Duct
± AIR CONDITIONINGAIR CONDITIONING UNIT
AC±23
2708 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
Page 17 of 1111

AC0WK±01
I02360
I02361
AC±24
± AIR CONDITIONINGAIR CONDITIONING UNIT
2709 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
REMOVAL
1. DISCHARGE REFRIGERANT FROM REFRIGERATION
SYSTEM
HINT:
At the time of installation, please refer to the following item.
Evacuate air from refrigeration system.
Charge system with refrigerant and inspect for leakage of refrig-
erant.
Specified amount: 600 ± 50 g (21.16 ± 1.76 oz.)
2. DRAIN ENGINE COOLANT FROM RADIATOR
HINT:
It is not necessary to drain out all coolant.
3. DISCONNECT LIQUID TUBE AND SUCTION HOSE
FROM A/C UNIT
Remove the bolt and slide the plate, then disconnect the both
tubes.
Torque: 10 N´m (100 kgf´cm, 7 ft´lbf)
NOTICE:
Cap the open fittings immediately to keep moisture or dirt
out of the system.
HINT:
At the time of installation, please refer to the following item.
Lubricate 2 new O±rings with compressor oil and install them
to the tubes.
4. DISCONNECT WATER HOSES FROM HEATER RA-
DIATOR PIPES
(a) Grips the claws of the hose clip and slide the hose clip
along the hose.
(b) Disconnect the water hose.
Page 18 of 1111
I02362
I02363
± AIR CONDITIONINGAIR CONDITIONING UNIT
AC±25
2710 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
5. REMOVE THESE PARTS:
(a) Cooler No.1 grommet
(b) Heater pipe grommet
(c) Drain hose grommet
(d) Instrument panel and reinforcement
(See page BO±91)
(e) Blower unit
(See page AC±30)
6. REMOVE 3 AIR DUCTS
(a) Remove the 2 screws and center air duct.
(b) Slide the floor carpet backward.
(c) Disconnect the wire harness clamps.
(d) Remove the 2 bolts and air ducts LH, RH.
7. REMOVE A/C UNIT
(a) Disconnect the connector.
(b) Remove the wire harness set nut.
(c) Disconnect the wire harness clamps.
(d) Remove the 2 nuts, bolt and A/C unit.
Page 19 of 1111

AC0WL±01
AC±26
± AIR CONDITIONINGAIR CONDITIONING UNIT
2711 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
DISASSEMBLY
1. REMOVE THESE PARTS:
(a) Wire harness
(b) Drain hose
2. REMOVE HEATER RADIATOR
(a) Remove the screw and clamp.
(b) Pull out the heater radiator.
3. REMOVE BLOWER MOTOR CONTROL RELAY
Remove the screw and blower motor control relay.
4. REMOVE AIR MIX SERVOMOTORS
Remove the 6 screws and both servomotors.
5. REMOVE AIR OUTLET SERVOMOTOR
Remove the 2 screws and servomotor.
6. REMOVE EXPANSION VALVE
(a) Pry out the packing.
HINT:
At the time of reassembly, please refer to the following item.
Do not reuse the packing.
(b) Using SST, remove the 2 bolts, then separate the expansion valve, tube connector and tube and ac-
cessory.
SST 07110±61050
Torque: 4.1N´m (42 kgf´cm, 36 in.´lbf)
HINT:
At the time of reassembly, please refer to the following item.
Lubricate 4 new O±rings with compressor oil and install them to the valve.
7. REMOVE EVAPORATOR TEMPERATURE SENSOR
(a) Disconnect the wire harness clamp.
(b) Using a screwdriver, pull out the sensor with bracket plate.
HINT:
Tape the screwdriver tip before use.
(c) Release the 2 claws and sensor from bracket plate.
8. REMOVE EVAPORATOR
(a) Using SST, remove the 2 bolts and tube and accessory.
SST 07110±61050
Torque: 4.1N´m (42 kgf´cm, 36 in.´lbf)
HINT:
At the time of reassembly, please refer to the following item.
Lubricate 2 new O±rings with compressor oil and install them to the tube.
(b) Remove the 4 screws and cover.
(c) Pull out the evaporator.
(d) Remove the plate from evaporator.
HINT:
At the time of reassembly, please refer to the following item.
If evaporator is replaced, add compressor oil to evaporator.
Add 40 cc (1.4fl.oz.)
Compressor oil: ND±OIL 8 or equivalent
9. REMOVE INSULATOR FROM HEATER CASE
10. REMOVE AIR DUCT
Remove the 4 screws and duct.
Page 433 of 1111

BR0K9±04
F06046
SST
F01655
SST
F06047
BR±50
± BRAKEHYDRAULIC BRAKE BOOSTER
2158 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
REMOVAL
NOTICE:
Before starting the work, make sure that the ignition
switch is OFF and depress the brake pedal more than
40 times.
As high pressure is applied to the brake actuator tube
No. 1, never deform it.
Until the work is over, do not turn the ignition switch
ON.
1. DRAW OUT FLUID WITH SYRINGE
NOTICE:
Do not let brake fluid remain on a painted surface. Wash it
off immediately.
2. REMOVE NO. 1 UNDER COVER (See page BO±88)
3. REMOVE END PAD AND NO. 1 SAFETY PAD
4. REMOVE NO. 7 HEATER TO REGISTER DUCT
5. DISCONNECT BRAKE LINES
Using SST, disconnect the 4 brake lines.
SST 09023±00100
Torque: 15 N´m (155 kgf´cm, 11 ft´lbf)
6. DISCONNECT LEFT FRONT WHEEL BRAKE LINE
Using SST, disconnect the left front wheel brake line from the
flexible hose.
SST 09023±00100
Torque: 15 N´m (155 kgf´cm, 11 ft´lbf)
7. REMOVE 2 BRAKE LINE CLAMPS
8. DISCONNECT LEVEL WARNING SWITCH CONNEC-
TOR
9. DISCONNECT 4 CONNECTORS
10. REMOVE PEDAL RETURN SPRING, CLIP AND CLE-
VIS PIN
11. REMOVE HYDRAULIC BRAKE BOOSTER ASSEMBLY
(a) Loosen the lock nut, then remove the clevis and lock nut.
Torque: 25 N´m (260 kgf´cm, 19 ft´lbf)
(b) Remove the 4 booster installation nuts.
Torque: 13 N´m (130 kgf´cm, 9 ft´lbf)
(c) Remove the booster assembly and gasket.
Page 470 of 1111

CO0A7±01
CO1242
Radiator Cap Tester
Radiator Cap
30° or More
B01882
Radiator Cap Tester
± COOLING (2JZ±GE)RADIATOR
CO±15
1553 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
ON±VEHICLE INSPECTION
1. REMOVE RADIATOR CAP
Remove the radiator cap from the radiator.
CAUTION:
To avoid the danger of being burned, do not remove the ra-
diator cap while the engine and radiator are still hot, as fluid
and steam can be blown out under pressure.
2. INSPECT RADIATOR CAP
NOTICE:
If the radiator cap has contaminations, always rinse
it with water.
Before using a radiator cap tester, wet the relief valve
and pressure valve with engine coolant or water.
When performing steps (a) and (b) below, keep the
tester at an angle of over 30° above the horizontal.
(a) Using a radiator cap tester, slowly pump the tester and
check that air is coming from the vacuum valve.
Pump speed: 1 push/(3 seconds or more)
NOTICE:
Push the pump at a constant speed.
If air is not coming from the vacuum valve, replace the radiator
cap.
(b) Pump the radiator cap tester, and measure the relief valve
opening pressure.
Pump speed: 1 push within 1 second
NOTICE:
This pump speed is for the first pump only (in order to close
the vacuum valve). After this, the pump speed can be re-
duced.
Standard opening pressure:
93 ± 123 kPa (0.95 ± 1.25 kgf/cm
2, 13.5 ± 17.8 psi)
Minimum opening pressure:
78 kPa (0.8 kgf/cm
2, 11.4 psi)
HINT:
Use the tester's maximum reading as the opening pressure.
If the opening pressure is less than minimum, replace the radia-
tor cap.
3. INSPECT COOLING SYSTEM FOR LEAKS
(a) Fill the radiator with coolant and attach a radiator cap tes-
ter.
(b) Warm up the engine.
(c) Pump it to 118 kPa (1.2 kgf/cm
2, 17.1 psi), and check that
the pressure does not drop.
If the pressure drops, check the hoses, radiator or water pump
for leaks. If no external leaks are found, check the heater core,
cylinder block and head.
4. REINSTALL RADIATOR CAP
Page 475 of 1111

CO09X±03
Z07402
Drain Plug
Drain Plug
B01611
Drain Plug
Rubber
HoseConnect
CO±2
± COOLING (2JZ±GE)COOLANT
1540 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
REPLACEMENT
1. DRAIN ENGINE COOLANT
(a) Remove the radiator cap.
CAUTION:
To avoid the danger of being burned, do not remove the ra-
diator cap while the engine and radiator are still hot, as fluid
and steam can be blown out under pressure.
(b) Loosen the 2 drain plugs (for the engine and radiator),
and drain the coolant.
HINT:
To prevent the coolant from spraying over the cylinder block,
connect the rubber hose (inside diameter 6 ± 8 mm) in the mar-
ket to the union pipe under the drain plug.
(c) Close the drain plugs.
Torque: 30 N´m (300 kgf´cm, 22 ft´lbf) for engine
2. FILL ENGINE COOLANT
(a) Slowly fill the system with coolant.
Use of improper coolants may damage engine cool-
ing system.
Use ºToyota Long Life Coolantº or equivalent and
mix it with plain water according to the manufac-
ture's directions.
Use of the coolant which includes more than 50%
[freezing protection down to ±35°C (±31°F)] or 60%
[freezing protection down to ±50°C (±58°F)] of eth-
ylene ±glycol is recommended, but not more than
70%.
NOTICE:
Do not use an alcohol type coolant or plain water
alone.
The coolant should be mixed with plain water (prefer-
able demineralized water or distilled water).
Capacity (w/ Heater):
7.7 liters (8.1 US qts, 6.8 lmp. qts)
(b) Install the radiator cap.
(c) Start the engine, and bleed the cooling system.
(d) Refill the reservoir with coolant until it reaches the ºFULLº
line.
3. CHECK ENGINE COOLANT FOR LEAKS
4. CHECK ENGINE COOLANT SPECIFIC GRAVITY COR-
RECTLY