2000 LEXUS GS400 cooling

CO0AI±03
B02071
CO±30
± COOLING (2JZ±GE)ELECTRIC COOLING FAN
1568 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
INSTALLATION
1. INSTALL ELECTRIC COOLING FAN
(a) Install the electric cooling fan with the 6 bolts.
Torque: 5.0 N´m (50 kgf´cm, 44 in.´lbf)
(b) Connect the upper radiator hose to the radiator.
(c) Connect the ECM outlet duct to the ECM box.
(d) Connect the wire for electric cooling fan to clamp on the
electric cooling fan.
(e) Connect the 2 electric cooling fan connectors.
(f) Connect the radiator reservoir hose to the radiator.
2. INSTALL AIR CLEANER AND MAF METER AS-
SEMBLY
3. INSTALL AIR CLEANER INLET
4. FILL WITH ENGINE COOLANT
5. START ENGINE AND CHECK FOR COOLANT LEAKS

B02035
ECT Switch
Connector
ECT
Switch
O±Ring
CO0AJ±01
P05962
Ohmmeter
± COOLING (2JZ±GE)ENGINE COOLANT TEMPERATURE (ECT) SWITCH
CO±31
1569 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
ENGINE COOLANT
TEMPERATURE (ECT) SWITCH
INSPECTION
1. DRAIN ENGINE COOLANT
2. REMOVE ECT SWITCH
(a) Disconnect the connector.
(b) Remove the ECT switch.
(c) Remove the O±ring from the ECT switch.
3. INSPECT ECT SWITCH
(a) Using an ohmmeter, check that there is no continuity be-
tween the terminals when the coolant temperature is
above 93°C (199°F).
If there is continuity, replace the switch.
(b) Using an ohmmeter, check that there is continuity be-
tween the terminals when the coolant temperature is be-
low 83°C (181°F).
If there is no continuity, replace the switch.
4. REINSTALL ECT SWITCH
(a) Install a new O±ring to the ECT switch.
(b) Install the ECT switch.
(c) Connect the connector.
5. REFILL WITH ENGINE COOLANT
6. START ENGINE AND CHECK FOR COOLANT LEAKS

B01376
Radiator
Fan Main
RelayCO0AK±01
B00019
Ohmmeter
Continuity
OhmmeterOhmmeter
No Continuity
Continuity21
5
43
B00020
Ohmmeter Ohmmeter
No Continuity
Continuity 2
1
5
43
Battery
CO±32
± COOLING (2JZ±GE)RADIATOR FAN MAIN RELAY
1570 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
RADIATOR FAN MAIN RELAY
INSPECTION
1. REMOVE RELAY BOX COVER
2. REMOVE RADIATOR FAN MAIN RELAY (Marking:
RAD FAN MAIN)
3. INSPECT RADIATOR FAN MAIN RELAY
(a) Inspect the relay continuity.
(1) Using an ohmmeter, check that there is continuity
between terminals 3 and 5.
If there is no continuity, replace the relay.
(2) Check that there is continuity between terminals 2
and 4.
If there is no continuity, replace the relay.
(3) Check that there is no continuity between terminals
1 and 2.
If there is continuity, replace the relay.
(b) Inspect the relay operation.
(1) Apply battery positive voltage across terminals 3
and 5.
(2) Using an ohmmeter, check that there is no continu-
ity between terminals 2 and 4.
If there is continuity, replace the relay.
(3) Check that there is continuity between terminals 1
and 2.
If there is no continuity, replace the relay.
4. REINSTALL RADIATOR FAN MAIN RELAY
5. REINSTALL RELAY BOX COVER

B00924
No.1 Cooling
Fan RelayCO0AL±01
B00021
Ohmmeter
Continuity
OhmmeterContinuity
41
3
2
B00022
No Continuity Ohmmeter
41
3
2
Battery
B01373
No.2 Cooling
Fan Relay
A00970
Continuity
Ohmmeter
No Continuity Continuity4
1
32
Ohmmeter
5
Ohmmeter
± COOLING (2JZ±GE)COOLING FAN RELAY
CO±33
1571 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
COOLING FAN RELAY
INSPECTION
1. INSPECT NO.1 COOLING FAN RELAY
(a) Remove the relay box cover.
(b) Remove the No.1 cooling fan relay. (Marking: FAN NO.1)
(c) Inspect the No.1 cooling fan relay continuity.
(1) Using an ohmmeter, check that there is continuity
between terminals 1 and 2.
If there is no continuity, replace the relay.
(2) Check that there is continuity between terminals 3
and 4.
If there is no continuity, replace the relay.
(d) Inspect the No.1 cooling fan relay operation.
(1) Apply battery positive voltage across terminals 1
and 2.
(2) Using an ohmmeter, check that there is no continu-
ity between terminals 3 and 4.
If there is continuity, replace the relay.
(e) Reinstall the No.1 cooling fan relay.
(f) Reinstall the relay box cover.
2. INSPECT NO.2 COOLING FAN RELAY
(a) Remove the relay box cover.
(b) Remove the No.2 cooling fan relay. (Marking: FAN NO.2)
(c) Inspect the No.2 cooling fan relay continuity.
(1) Using an ohmmeter, check that there is continuity
between terminals 1 and 2.
If there is no continuity, replace the relay.
(2) Check that there is continuity between terminals 3
and 4.
If there is no continuity, replace the relay.
(3) Check that there is no continuity between terminals
3 and 5.
If there is continuity, replace the relay.

A00971
Ohmmeter
No ContinuityOhmmeter
Continuity 4
1
32
5
Battery
B01375
No.3 Cooling
Fan Relay
A00968No ContinuityContinuity 12 Ohmmeter
5Ohmmeter
3
A00969
Ohmmeter
Continuity1
32
5
Battery
CO±34
± COOLING (2JZ±GE)COOLING FAN RELAY
1572 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
(d) Inspect the No.2 cooling fan relay operation.
(1) Apply battery positive voltage across terminals 1
and 2.
(2) Using an ohmmeter, check that there is no continu-
ity between terminals 3 and 4.
If there is continuity, replace the relay.
(3) Using an ohmmeter, check that there is continuity
between terminals 3 and 5.
If there is no continuity, replace the relay.
(e) Reinstall the No.2 cooling fan relay.
(f) Reinstall the relay box cover.
3. INSPECT NO.3 COOLING FAN RELAY
(a) Remove the relay box cover.
(b) Remove the No.3 cooling fan relay. (Marking: FAN NO.3)
(c) Inspect the No.3 cooling fan relay continuity.
(1) Using an ohmmeter, check that there is continuity
between terminals 1 and 2.
If there is no continuity, replace the relay.
(2) Check that there is no continuity between terminals
3 and 5.
If there is continuity, replace the relay.
(d) Inspect the No.3 cooling fan relay operation.
(1) Apply battery positive voltage across terminals 1
and 2.
(2) Using an ohmmeter, check that there is continuity
between terminals 3 and 5.
If there is no continuity, replace the relay.
(e) Reinstall the No.3 cooling fan relay.
(f) Reinstall the relay box cover.

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.

B01941
Drain Hose
CO±6
± COOLING (2JZ±GE)WATER PUMP
1544 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
(e) Remove the 6 bolts, water pump and gasket.
(f) Remove the drain hose.
(g) Remove the O±ring from the cylinder block.

CO0A0±01
B01574
± COOLING (2JZ±GE)WATER PUMP
CO±7
1545 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
INSPECTION
INSPECT WATER PUMP
Turn the pulley seat, and check that the water pump bearing is
not rough or noisy.
If necessary, replace the water pump.