Lexus SC300 / Lexus SC400. Manual — part 317

CHECK AND REPLACEMENT OF
ENGINE COOLANT

1.

CHECK ENGINE COOLANT LEVEL AT RESERVE TANK
The coolant level should be above the ”COLD LEVEL” at nor-
mal temperature (20

°

C (68

°

F)).

If low, check for leaks and add coolant up to the ”COLD LEV-
EL”.

2.

CHECK ENGINE COOLANT QUALITY
There should not be any excessive deposits of rust or scales
around the radiator cap or reservoir tank filler hole, and the
coolant should be free from oil.
If excessively dirty, clean the coolant passages and replace
the coolant.

3.

REPLACE ENGINE COOLANT
(a) Remove the radiator cap from the reservoir tank.
CAUTION: To avoid the danger of being burned, do not
remove the cap while the engine and radiator are still hot,
as fluid and steam can be blown out under pressure.

(b) Remove the filler plug from the water inlet housing.

(c) Loosen the three drain plugs on the radiator and

cylinder block, drain the coolant from the radiator and
engine.

(d) Clean the coolant passages.
(e) Close the three drain plugs.

Torque (Engine drain plug):

18 N

⋅

m (180 kgf

⋅

cm, 13 ft

⋅

lbf)

CO–6

–

COOLIING SYSTEM

Check and Replacement of Engine Coolant

(f) Slowly add coolant to water inlet housing until it is full.

•

Use a good brand of ethylene–glycol base coolant,
mixed according to the manufacturer’s directions.

•

Using coolant which includes more than 50%
ethylene–glycol (but not more 70%) than is
recommended.

NOTICE:

•

Do not use alcohol type coolant.

•

The coolant should be mixed with demineralized water or

distilled water.

Capacity (w/ Heater):

10.8 liters (11.4 US qts, 9.5 lmp. qts)

(g) Reinstall a new gasket and filler plug to the water inlet

housing.

Torque: 44 N

⋅

m (450 kgf

⋅

cm, 33 ft

⋅

lbf)

(h) Slowly add coolant to reservoir tank until it is full.

(i)

Reinstall the radiator cap.

(j)

Bleed the cooling system.

•

Start the engine, and open the heater water valve.

•

Maintain the engine speed at 2,000 rpm, and warm
up the engine.

(k) Check for leaks.
(l)

Recheck the coolant level and refill as necessary.

–

COOLIING SYSTEM

Check and Replacement of Engine Coolant

CO–7

WATER PUMP

COMPONENTS FOR REMOVAL AND
INSTALLATION

REMOVAL OF WATER PUMP

1.

REMOVE TIMING BELT
(See steps 1 to 35 on pages

EM–35

to 43)

2.

REMOVE RH IGNITION COIL
(a) Disconnect the ignition coil connector.
(b) Remove the two bolts and ignition coil.

3.

REMOVE WATER INLET AND INLET HOUSING
(a) Disconnect the water by–pass hose from the water inlet

housing.

CO–8

–

COOLIING SYSTEM

Water Pump

(b) Remove the two bolts holding the water inlet housing to

the water pump.

(c) Pull out the water inlet and inlet housing assembly.
(d) Remove the O–ring from the water inlet housing.

4. REMOVE

WATER

PUMP

(a) Remove the five mounting bolts, two stud bolts and nut.

(b) Remove the water pump by prying the portions between

the water pump and cylinder block with a screwdriver.

(c) Remove the O–ring from the water by–pass pipe.

INSPECTION OF WATER PUMP

INSPECT WATER PUMP

Turn the pulley and check that the water pump bearing
moves smoothly and quietly.

–

COOLIING SYSTEM

Water Pump

CO–9