2000 LEXUS GS400 engine

CO09Z±03
A02725Turn
Loosen
B01614
Water Bypass Outlet
No.1 Water Bypass Hose
B01638
Clamp Bracket
Connector Bracket
B01572No.2 Water Bypass Pipe
± COOLING (2JZ±GE)WATER PUMP
CO±5
1543 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
REMOVAL
1. REMOVE RADIATOR ASSEMBLY
(See page CO±18)
2. REMOVE DRIVE BELT AND WATER PUMP PULLEY
(a) Loosen the 4 nuts holding the water pump pulley to the
water pump.
(b) Loosen the drive belt tension by turning the drive belt ten-
sioner clockwise, and remove the drive belt.
(c) Remove the 4 nuts and water pump pulley.
3. REMOVE TIMING BELT AND IDLER PULLEY
(See page EM±16)
4. REMOVE WATER BYPASS OUTLET AND NO.1
WATER BYPASS PIPE
(a) Remove the 2 bolts, water bypass outlet and No.1 water
bypass pipe.
(b) Remove the 3 O±rings from the water bypass outlet and
No.1 water bypass pipe.
5. REMOVE WATER INLET AND THERMOSTAT
(See page CO±11)
6. REMOVE WATER PUMP
(a) Loosen the nut and remove the bolt, slide the generator
away from the water pump.
(b) Remove the bolt, and disconnect the clamp bracket (for
engine wire).
(c) Remove the bolt, and disconnect the connector bracket
(for crankshaft position sensor connector).
(d) Remove the 2 nuts, and disconnect the No.2 water by-
pass pipe from the water pump.

CO0A1±03
P03945
New
O±Ring
P02574
New Gasket
A02801
AB A
B
A
B
B
B
B01614
New O±Ring
CO±8
± COOLING (2JZ±GE)WATER PUMP
1546 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
INSTALLATION
1. INSTALL WATER PUMP
(a) Install a new O±ring to the cylinder block.
(b) Install the drain hose.
(c) Install a new gasket to the water pump.
(d) Connect the water pump to the water bypass pipe. Do not
install the nut yet.
(e) Install the water pump with the 2 bolts (A) and 4 bolts (B).
Torque: 21 N´m (210 kgf´cm, 15 ft´lbf)
HINT:
Hand tighten the (A) bolts first.
(f) Install the 2 nuts holding the No.2 water bypass pipe to
the water pump.
Torque: 21 N´m (210 kgf´cm, 15 ft´lbf)
(g) Install the connector bracket (for crankshaft position sen-
sor connector) with the bolt.
(h) Install the clamp bracket (for engine wire) with the bolt.
(i) Install the generator with the bolt and nut.
Torque: 40 N´m (400 kgf´cm, 30 ft´lbf)
2. INSTALL THERMOSTAT AND WATER INLET
(See page CO±13)
3. INSTALL NO.1 WATER BYPASS PIPE AND WATER
BYPASS OUTLET
(a) Install 2 new O±rings to the No.1 water bypass pipe.
(b) Install a new O±ring and the water bypass outlet with the
2 bolts.
Torque: 9.0 N´m (90 kgf´cm, 80 in.´lbf)
4. INSTALL IDLER PULLEY AND TIMING BELT
(See page EM±23)
5. INSTALL WATER PUMP PULLEY AND DRIVE BELT
Torque: 14 N´m (140 kgf´cm, 10 ft´lbf)

EC00B±05
± EMISSION CONTROL (2JZ±GE)EMISSION CONTROL SYSTEM
EC±1
1452 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
EMISSION CONTROL SYSTEM
PURPOSE
The emission control systems are installed to reduce the amount of CO, HC and NOx exhausted from the
engine (3) and (4)), to prevent the atmospheric release of blow±by gas±containing HC (1) and evaporated
fuel containing HC being released from the fuel tank (2).
The function of each system is shown in these table.
SystemAbbreviationFunction
(1) Positive Crankcase Ventilation
(2) Evaporative Emission Control
(3) Three±Way Catalytic Converter
(4) Sequential Multiport Fuel Injection *PCV
EVAP
TWC
SFIReduces blow±by gas (HC)
Reduces evaporated HC
Reduces CO, HC and NOx
Injects a precisely timed, optimum amount of fuel for reduced exhaust
emissions
Remark: * For inspection and repair of the SFI system, refer to the SF section this manual.

EC0DF±01
B01589
Air Cleaner, MAF Meter
and Intake Air Resonator
AssemblyPCV Hose
PS Air Hose
Air Cleaner Inlet MAF Meter Connector
Heated Oxygen Sensor
(Bank 1 Sensor 1)EVAP Hose

Gasket
Exhaust Manifold (with Front TWC)
Pipe Support Bracket
N´m (kgf´cm, ft´lbf)

Non±reusable partWire Grommet
Front Exhaust Pipe
: Specified torque
Heated Oxygen Sensor
(Bank 2 Sensor 1)
Heated Oxygen Sensor
(Bank 1 Sensor 2)

Gasket
40 (408, 30)
x 8
45 (450, 32)
44 (440, 32)
Engine Wire Clamp
Case Clamp

Clamp
44 (440, 32)
EC±12± EMISSION CONTROL (2JZ±GE)THREE±WAY CATALYTIC CONVERTER (TWC)
SYSTEM
1463 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
THREE±WAY CATALYTIC CONVERTER (TWC) SYSTEM
COMPONENTS

EC050±04
B09011
± EMISSION CONTROL (2JZ±GE)THREE±WAY CATALYTIC CONVERTER (TWC)
SYSTEMEC±15
1466 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
REPLACEMENT
1. REMOVE ENGINE COVER
2. REMOVE AIR CLEANER INLET
3. REMOVE AIR CLEANER, MAF METER AND INTAKE
AIR RESONATOR ASSEMBLY (See page EM±62)
4. DISCONNECT HEATED OXYGEN SENSORS FROM
EXHAUST MANIFOLD
(a) Disconnect the 3 oxygen sensor connectors.
(b) Disconnect the 2 oxygen sensors (bank 1 sensor 1, 2)
from the exhaust manifold.
5. REMOVE FRONT EXHAUST PIPE (WITH REAR TWC)
(a) Take out the front side of the floor carpet.
(b) Disconnect the oxygen sensor connector.
(c) Remove the 2 bolts and pipe support bracket.
(d) Remove the 5 bolts, front exhaust pipe and 3 gaskets.
6. REMOVE EXHAUST MANIFOLD (WITH FRONT TWC)
(a) Using a 14 mm deep socket wrench, remove the 8 nuts,
the exhaust manifold and 2 gaskets.
(b) Remove the heated oxygen sensor (bank 2 sensor 1)
form the exhaust manifold.
7. REINSTALL NEX EXHAUST MANIFOLD (WITH FRONT
TWC)
(a) Install the heated oxygen sensor (bank 2 sensor 1) to the
exhaust manifold.
Torque: 45 N´m (450 kgf´cm, 33 ft´lbf)
(b) Install 2 new gaskets to the cylinder head.
(c) Using a 14 mm deep socket wrench, install new exhaust
manifold with 8 new nuts. Uniformly tighten the nuts in
several passes.
Torque: 40 N´m (408 kgf´cm, 30 ft´lbf)
8. REINSTALL FRONT EXHAUST PIPE (WITH REAR
TWC)
(a) Reinstall new 3 gaskets, and front exhaust pipe with 5
bolts and support bracket.
(b) Reinstall the pipe support bracket with 2 bolts.
9. RECONNECT HEATED OXYGEN SENSORS TO EX-
HAUST MANIFOLD
(a) Install the 2 oxygen sensors (bank 1 sensor 1, 2) to the
exhaust manifold.
Torque: 45 N´m (450 kgf´cm, 33 ft´lbf)
(b) Connect the 3 oxygen sensor connectors.
10. REINSTALL AIR CLEANER, MAF MATER AND INTAKE
AIR RESONATOR ASSEMBLY (See page EM±68)
11. REINSTALL AIR CLEANER INLET
12. REINSTALL ENGINE COVER

EC04X±05
B02023
PCV Valve
P02006Cylinder Head SideClean Hose
P02477
Intake Air
Connector Side
B02817
Side
Line
55° EC±4
± EMISSION CONTROL (2JZ±GE)POSITIVE CRANKCASE VENTILATION (PCV)
SYSTEM
1455 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
POSITIVE CRANKCASE
VENTILATION (PCV) SYSTEM
INSPECTION
1. REMOVE ENGINE COVER
Remove 4 nuts and engine cover.
2. REMOVE PCV VALVE
(a) Disconnect the PCV hose from the PCV valve.
(b) Remove the PCV valve.
3. INSTALL CLEAN HOSE TO PCV VALVE
4. INSPECT PCV VALVE OPERATION
(a) Blow air into the cylinder head side, and check that air
passes through easily.
CAUTION:

Do not suck air through the valve.

Petroleum substances inside the valve are harmful.
(b) Blow air into the intake air connector side, and check that
air passes through with difficulty.
If operation is not as specified, replace the PCV valve.
5. REMOVE CLEAN HOSE FROM PCV VALVE
6. REINSTALL PCV VALVE
The port faces in the direction indicated in the illustration.

S00601
± EMISSION CONTROL (2JZ±GE)POSITIVE CRANKCASE VENTILATION (PCV)
SYSTEMEC±5
1456 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
7. VISUALLY INSPECT HOSES, CONNECTIONS
AND GASKETS
Check for cracks, leaks or damage.
8. REINSTALL ENGINE COVER
Install the engine cover with the 4 nuts.

EC0BD±02
B02709
Gasket
Vacuum
Valve Pressure
Valve
B06544
Vacuum
Gauge
B01982
LEXUS Hand±Held Tester
DLC 3
B06548Battery
± EMISSION CONTROL (2JZ±GE)EVAPORATIVE EMISSION (EVAP) CONTROL SYSTEM
EC±7
1458 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
INSPECTION
1. INSPECT LINES AND CONNECTORS
Visually check for loose connections, sharp bends or damage.
2. INSPECT FUEL TANK FILLER PIPE
Visually check for deformation, cracks or fuel leakage.
3. VISUALLY INSPECT FUEL TANK CAP
Check if the cap and/or gasket are deformed or damaged.
If necessary, repair or replace the cap.
4. INSPECT EVAP SYSTEM LINE
(a) Warm up the engine and stop the engine.
Allow the engine to warm up to normal operating tempera-
ture.
(b) Install a vacuum gauge (EVAP control system test equip-
ment vacuum gauge) to the EVAP service port on the
purge line.
(c) LEXUS Hand±Held Tester:
Forced driving of the VSV for the EVAP.
(1) Connect a LEXUS hand±held tester to the DLC3.
(2) Start the engine.
(3) Push the LEXUS hand±held tester main switch ON.
(4) Use the ACTIVE TEST mode on the LEXUS hand±
held tester to operate the VSV for the EVAP.
(d) If you have no LEXUS Hand±Held Tester:
Forced driving of the VSV for the EVAP.
(1) Disconnect the VSV connector for the EVAP.
(2) Connect the positive (+) and negative (±) leads from
the battery to the VSV terminals for the EVAP.
(3) Start the engine.