Lexus RX300 (MCU15). Manual — part 186

CO083–03

B04153

Stud Bolt

Jiggle Valve

15

° 15°

–

COOLING

THERMOSTAT

CO–13

LEXUS RX300 (RM785E)

INSTALLATION

1.

PLACE THERMOSTAT IN WATER PUMP

(a)

Install a new gasket on to the thermostat.

(b)

Align the thermostat jiggle valve with the upper stud bolt,
and insert the thermostat in the water inlet housing.

HINT:
The jiggle valve may be set within 15

° of either side of the pre-

scribed position.
2.

INSTALL WATER INLET

Install the water inlet with the 3 nuts.

Torque: 8 N·m (80 kgf·cm, 69 in.·lbf)

3.

INSTALL WATER INLET PIPE

(a)

Install a new O–ring to the water inlet pipe.

(b)

Apply soapy water to the O–ring.

(c)

Connect the water inlet pipe to the water inlet.

(d)

Install the bolt holding the water inlet pipe to the cylinder
head.
Torque: 19.5 N·m (200 kgf·cm, 14 ft·lbf)

4.

INSTALL ENGINE WIRE PROTECTOR

5.

CONNECT WATER TEMPERATURE SWITCH CON-
NECTOR

6.

REINSTALL AIR CLEANER CAP AND AIR CLEANER
CASE

7.

FILL WITH ENGINE COOLANT

8.

START ENGINE AND CHECK FOR LEAKS

9.

RECHECK ENGINE COOLANT LEVEL

CO06G–01

CO–14

–

COOLING

RADIATOR

LEXUS RX300 (RM785E)

RADIATOR

ON–VEHICLE CLEANING

Using water or a steam cleaner, remove any mud or dirt from the radiator core.
NOTICE:
If using a high pressure type cleaner, be careful not to deform the fins of the radiator core. (i.e. Main-
tain a distance between the cleaner nozzle and radiator core.)

CO06H–08

Z00570

Radiator Cap Tester

30

° or More

Radiator Cap

B04154

Radiator Cap
Tester

–

COOLING

RADIATOR

CO–15

LEXUS RX300 (RM785E)

ON–VEHICLE INSPECTION

1.

REMOVE 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.
2.

INSPECT RADIATOR CAP

NOTICE:

S

If the radiator cap has contaminations, always rinse
it with water.

S

When performing steps (a) and (b) below, keep the ra-
diator cap tester at an angle of over 30

° above the hor-

izontal.

S

Before using a radiator cap tester, wet the relief valve
and pressure valve with engine coolant or water.

(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 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 – 122 kPa (0.95 – 1.25 kgf/cm

2

, 13.4 – 17.6 psi)

Minimum opening pressure:
78 kPa (0.8 kgf/cm

2

, 11.2 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

CO0IH–03

B12314

A/C Condenser

Radiator Side Air Seal

Radiator Lower Grille

Discharge Hose

Front Bumper
Energy Absorber

Front Bumper Cover

Engine Under Cover

Discharge Tube

x 5

CO–16

–

COOLING

RADIATOR

LEXUS RX300 (RM785E)

COMPONENTS