Page 269 of 4770
3. INSPECT ECT SENSOR RESISTANCE
Using an ohmmeter, measure the resistance between
the terminals.
Resistance:
Refer to the graph above
If the resistance is not as specified, replace the
sensor.
4. REINSTALL ECT SENSOR
5. FILL WITH ENGINE COOLANT
ENGINE COOLANT TEMPERATURE
(ECT) SENSOR
ECT SENSOR INSPECTION
1. DRAIN ENGINE COOLANT
2. REMOVE ECT SENSOR
± 5S±FE ENGINEMFI/SFI SYSTEMEG1±219
Page 289 of 4770

RADIATOR
The radiator performs the function of cooling the coolant which has passed through the water
jacket and become hot, and it is mounted in the front of the vehicle. The radiator consists of an
upper tank and lower tank, and a core which connects the two tanks. The upper tank contains the
inlet for coolant from the water jacket and the filler inlet. It also has a hose attached through
which excess coolant or steam can flow. The lower tank has an outlet and drain cock for the
coolant. The core contains many tubes through which coolant flows from the upper tank to the
lower tank as well as to cooling fins which radiate heat away from the coolant in the tubes. The
air sucked through the radiator by the electric fan, as well as the wind generated by the vehicle's
travel, passes through the radiator, cooling the coolant. Models with automatic transmission
include an automatic transmission fluid cooler built into the lower tank of the radiator. A fan with
an electric motor is mounted behind the radiator to assist the flow of air through the radiator. The
fan operates when the engine coolant temperature becomes high in order to prevent it from be-
coming too high.
RADIATOR CAP
The radiator cap is a pressure type cap which seals the radiator, resulting in pressurization of the
radiator as the coolant expands. The pressurization prevents the coolant from boiling even when
the engine coolant temperature exceeds 100°C (212°F). A relief valve (pressurization valve) and a
vacuum valve (negative pressure valve) are built into the radiator cap. The relief valve opens and
lets steam escape through the overflow pipe when the pressure generated inside the cooling sys-
tem exceeds the limit (coolant temperature: 110±120°C (230±248°F), pressure; 58.8103.0 kpa
(0.6±1.05 kgf/cm
2, 8.5±14.9 psi). The vacuum valve opens to alleviate the vacuum which develops
in the cooling system after the engine is stopped and the engine coolant temperature drops. The
valve's opening allows the coolant in the reservoir tank to return to the cooling system.
RESERVOIR TANK
The reservoir tank is used to catch coolant which overflows from the cooling system as a result
of volumetric expansion when the coolant is heated. The coolant in the reservoir tank returns to
the radiator when the coolant temperature drops, thus keeping the radiator full at all times and
avoiding needless coolant loss.
Check the reservoir tank level to learn if the coolant needs to be replenished.
WATER PUMP
The water pump is used for forced circulation of coolant through the cooling system. It is
mounted on the front of the cylinder block and driven by a timing belt.
THERMOSTAT
The thermostat has a wax type bypass valve and is mounted in the water inlet housing. The
thermostat includes a type of automatic valve operated by fluctuations in the engine coolant
temperature. This valve closes when the engine coolant temperature drops, preventing the
circulation of coolant through the engine and thus permitting the engine to warm up rapidly. The
valve opens when the engine coolant temperature has risen, allowing the circulation of coolant.
Wax inside the thermostat expands when heated and contracts when cooled. Heating the wax
thus generates pressure which overpowers the force of the spring which keeps the valve closed,
thus opening the valve. When the wax cools, its contraction allows the force of the spring to take
effect once more, closing the valve. The thermostat in this engine operates at a temperature of
82C (180F).
± 5S±FE ENGINECOOLING SYSTEMEG1±239
Page 290 of 4770
PREPARATION
SST (SPECIAL SERVICE TOOLS)
RECOMMENDED TOOLS
09082±00050 TOYOTA Electrical Tester Set09230±01010 Radiator Service Tool Set
6.3 liters (6.7 US qts, 5.5 Imp. qts)Engine coolant temperature switch
Engine coolant temperature switch 09228±06500 Oil Filter Wrench
Engine coolant (w/ Heater)
EQUIPMENT
Radiator cap tester
Ethylene±glycol base
COOLANT
Torque wrenchThermometer
Classification Capacity Heater
Item
± 5S±FE ENGINECOOLING SYSTEMEG1±240
Page 302 of 4770
2. DRAIN ENGINE COOLANT (See page EG1±241)
3. w/ CRUISE CONTROL SYSTEM:
REMOVE CRUISE CONTROL ACTUATOR COVER
4. DISCONNECT ENGINE COOLANT TEMPERATURE
SWITCH CONNECTOR FROM FAN SHROUD
5. DISCONNECT ELECTRIC COOLING FAN
CONNECTORS
9. REMOVE RADIATOR AND ELECTRIC COOLING
FANS
(a) Remove the 2 bolts and 2 upper supports.
(b) Lift out the radiator.
(c) Remove the 2 lower radiator supports. 6. DISCONNECT RADIATOR HOSES
(a) Disconnect the upper hose from the radiator side.
(b) Disconnect the lower from the water inlet pipe.
7. DISCONNECT ENGINE COOLANT RESERVOIR
HOSE
10. REMOVE RADIATOR LOWER HOSE
11. A/T:
REMOVE A/T OIL COOLER HOSES 8. A/T:
DISCONNECT OIL COOLER HOSES
± 5S±FE ENGINECOOLING SYSTEMEG1±252
Page 303 of 4770
14. REMOVE ENGINE COOLANT TEMPERATURE
SWITCH
(a) Remove the engine coolant temperature switch.
(b) Remove the 0±ring. 13. REMOVE ELECTRIC COOLING FANS FROM
RADIATOR
Remove the 8 bolts and cooling fans.12. REMOVE ENGINE COOLANT TEMPERATURE
SWITCH WIRE
± 5S±FE ENGINECOOLING SYSTEMEG1±253
Page 308 of 4770
(d) Inspect for water leaks.
HINT: On radiators with resin tanks, there is a clear±
ance between the tank and lock plate where a minute
amount of air will remain, giving the appearance of an
air leak when the radiator is submerged in water.
Therefore, before performing the water leak test, first
switch the radiator around in the water until all air
bubbles disappear.
7. PAINT LOCK PLATES
HINT: If the water leak test checks out okay, allow the
radiator to completely dry and then paint the lock
plates.
RADIATOR INSTALLATION
(See Components for Removal and installation)
1. INSTALL ENGINE COOLANT TEMPERATURE
SWITCH
(a) Install a new O±ring to the engine coolant tempera±
ture switch.
(b) Install the engine coolant temperature switch.
2. INSTALL ELECTRIC COOLING FANS TO RADIATOR
Install the cooling fans with the 8 bolts.
3. INSTALL ENGINE COOLANT TEMPERATURE
SWITCH WIRE
± 5S±FE ENGINECOOLING SYSTEMEG1±258
Page 310 of 4770
10. CONNECT ELECTRIC COOLING FAN CONNECTORS
11. CONNECT ENGINE COOLANT TEMPERATURE
SWITCH CONNECTOR TO FAN SHROUD
12. w/ CRUISE CONTROL SYSTEM:
INSTALL CRUISE CONTROL ACTUATOR COVER
13. FILL WITH ENGINE COOLANT
(See page EG1±241)
14. CONNECT NEGATIVE (±) TERMINAL CABLE TO
BATTERY
15. START ENGINE AND CHECK FOR LEAKS
16. A/T:
CHECK AUTOMATIC TRANSMISSION (A/T) FLUID
LEVEL
NOTICE: Do not overfill.
± 5S±FE ENGINECOOLING SYSTEMEG1±260
Page 312 of 4770

9=4 ±01
ELECTRIC COOLING FAN COMPONENTS
INSPECTION
1. INSPECT ENGINE COOLANT TEMPERATURE
SWITCH
(a) Using an ohmmeter, check that there is no continuity
between the terminals when the engine coolant tem±
perature is above 93C (199F).
(b) Using an ohmmeter, check that there is continuity
between the terminals when the engine coolant tem±
perature is below 83C (181 F).
If continuity is not as specified, replace the switch. 2. DISCONNECT ENGINE COOLANT TEMPERATURE
SWITCH CONNECTOR
Check that the cooling fan rotates.
If not, check the cooling fan relay, cooling fan, engine
main relay and fuse, and check for a short circuit
between the cooling fan relay and engine coolant
temperature switch.
3. CONNECT ENGINE COOLANT TEMPERATURE
SWITCH CONNECTOR
ON±VEHICLE INSPECTION
Low Temperature (Below 83
C (181F))
1. TURN IGNITION SWITCH ªONº
Check that the cooling fan stops.
If not, check the cooling fan relay and engine coolant
temperature switch, and check for a separated con±
nector or severed wire between the cooling fan relay
and engine coolant temperature switch.
High Temperature (Above 93C (199F))
4. START ENGINE
(a) Raise engine coolant temperature to above 93C
(199F).
(b) Check that the cooling fan rotates.
If not, replace the engine coolant temperature switch.
± 5S±FE ENGINECOOLING SYSTEMEG1±262