thermostat TOYOTA CELICA 1987 Service Repair Manual

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co-2 COOLING SYSTEM - Description
,- I . . .
DESCRlqTlON
This engine utilizes a pressurized water forced circulation cooling system which includes a thermostat equip-
ped mounted on the outlet side.
5 7M-GE
Throttle Body
ISC Valve
/
To Radiator
RHD
/
From Heater
rM-GTE
/
To Heater From Heat: ISC Valve
To Radiator
COGS
COOF

. COOLING SYSTEM - Description
co;3
RESERVOIR TANK
The reservoir tank is used to catch coolant
which overflows the cooling systein 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 rep-
lenished.
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
V-ribbed belt,
THERMOSTAT I The cooling system is composed of the water
jacket (inside the cylinder block and cylinder head),
radiator, water pump, thermostat, cooling fan,
hoses and other components.
Coolant which is heated in the water
jacket is
pumped to the radiator, through which a cooling
fan blows air to cool the coolant as it passes
through. Coolant which has been cooled is then
sent back to the engine by the water pump, where
it cools the engine.
The water jacket is a network of channels in the
shell of the cylinder block and cylinder head
through which coolant passes. It is designed to
provide adequate cooling of the cylinders are com-
bustion chambers which become the hottest dur-
ing engine operation.
F(/ “ IATOR
The radiator performs the function of cooling
the coolant which has passed through the water
jacket and become hot, and 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 filter inlet. It
also has a hose attached through which excess
coolant or steam can flow. The lower tank contains
the outlet for coolant and the drain cock. The core
contains many tubes through which coolant flows
from the upper tank to the lower tank as well as
cooling fins which radiate heat away from the coo-
lant in the tubes. The air sucked through the radia-
tor by cooling fan, as well as the wind generated
by the vehicle’s travel, passes through the radia-
tor, cooling it. Models with automatic transmission
incrl*-le an automatic transmission fluid cooler built
in:.
.le lower tank of the radiator.
RADIATOR CAP
The radiator cap is a pressure type can which
seals the radiator, resulting in pressurization of the
radiator as the coolant expands. The pressuriza-
tion prevents the coolant from boiling even when
the coolant temperature exceeds 100°C. A relief
valve (pressurization valve) and a vacuum valve
(negative pressure valve) are built into the radiator
zap. The relief valve opens and lets steam escape
:hrough the overflow pipe when the pressure
3enerated inside the cooling system exceeds the
imit (coolant temperature:
110 - 1 20°C, (230
- 248”F), pressure; 0.3 - 1 .O kg/cmz, (4.3 - 14.2
)si, 29.4 - 98.1 kPa). The vacuum valve opens to
3ljeviate the vacuum which develops in the coolant
system after the engine is stopped and the coolant
emperature drops. The valve’s opening allows the
)ressure in the cooling system to return to the
Qclant in the reservoir tank. The thermostat has a wax type and is mounted
in the. water outlet housing. The thermostat
includes a type of automatic valve operated by
fluctuations in the coolant temperature. This valve
closes when the coolant temperature drops, pre-
venting the circulation of coolant through the
engine and thus permitting the engine to warm up
rapidly. The valve opens when the coolant tem-
perature has risen, allowing the circulation of coo-
lant. 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 causes the force of the
spring to take effect once more, closing the valve.
The thermostat in this engine operates at a tem-
perature of 88”C(19O”F).
I
I

co-4 CQOLING SYSTEM - Troubleshootmg
TROUBLESHOOTING
, Problem
Engine overheats Possible cause
Alternator drive belt loose or missing
Dirt, leaves or insects in radiator or
condenser
Hoses, water pump, water outlet
housing, radiator, heater, core plugs
or head gasket leakage
Thermostat faulty
Ignition timing
retarded
Fluid coupling faulty
Radiator hose plugged or rotted
Water pump faulty
Radiator plugged or cap faulty
Cylinder head or block cracked or
phwd Remedy
Adjust or replace belt
Clean radiator or condenser
Repair as necessary
Check thermostat
Set timing
Replace fluid coupling
Replace hose
Replace water pump
Check radiator
Repair as necessary Page
CH-4
CO-8
EM-l 7
CO-6
CO-6
co-9

CO-8 -. COOLING SYSTEM L Thermostat
._
Valve Lift
i
t-
THERMOSTAT
REMOVAL OF THERMOSTAT
REMOVE WATER OUTLET AND THERMOSTAT
(a) Remove two bolts, water outlet and thermostat with
gasket from the water outlet, housing.
(b) Remove the gasket from the thermostat.
INSPECTION OF THERMOSTAT
NOTE: Thermostat is numbered according to the valve
opening temperature.
(a)
Immerse the thermostat in water and heat the water
gradually.
(b)
Check the valve opening temperature.
Valve opening temperature:
86 - 90°C (187
- 194°F)
If the valve opening temperature is not within specifica-
tion, replace the thermostat.
(c) Check the vatve lift.
Valve lift:
8 mm (0.31 in.) or more at
100°C (212°F)
If the valve lift is less than specification, replace the ther-
mostat.
(d) Check that the valve spring is tight when the ther-
mostat is fully closed.
If necessary, replace the thermostat.
INSTALLATION OF THERMOSTAT
INSTALL THERMOSTAT AND WATER OUTLET
(a) Place a new gasket to the thermostat.
(b) Install the thermostat with the jiggle valve facin
upward as shown in the illustration, and water outlc
with the two bolts.
,

EM-28
ENGINE MECliANICAL - Titiingj Belt.
TIMING B’ELT
-.
COMPONENTS
No. 3 Timing Belt Cover Camshaft Timing Pulley
I I ImIng oen
I
Crankshaft Pulley
kg-cm (ft-lb, N-ml : Specified torque
EM30f 31
REMOVAL OF TIMING BELT
1.
REMOVE SPARK PLUGS
2. REMOVE WATER OUTLET
Remove the two bolts, water outlet and thermostat with
. gasket.
3. .(with A/C)
REMOVE A/C BELT
4. REMOVE FAN AND ALTERNATOR DRIVE BELT
5.
REMOVE PS BELT

EM-36 ENGINE MECHANICAL - Timinn Belt
EM302
EM301
,
A
Alternator
1
EM3000
CORRECT WRONG
WRONG 14. INSTALL ALTERNATOR DRIVE BELT AND FAN
Torque: Fan 55 kg-cm (48 in.-lb, 6.4 N-m)
Adjusting bolt 130 kg-cm (9 ft-lb, 13 N*m)
15. (with A/C)
INSTALL A/C BELT
16. INSTALL WATER OUTLET
install the thermostat with a new gasket and water outlet
with the two bolts.
17. INSTALL SPARK PLUGS
(See page 10-7)
16. ADJUST DRIVE BELTS
Install and adjust the drive belts.
Drive belt deflection with 10 kg or 22 lb:
New belt
A 10 - 12 mm IO.39 - 0.47 in.)
B 7 - 8 mm (0.28 7 0.31 in.)
C MA 7 - 9.5 mm (0.28 - 0.374 in.)
MS 7.5 - 9.5 mm (0.296 - 0.374 in.1
Used belt
A 15 - 17 mm (0.59 - 0.67 in.1 ,
B 9 - 11 mm (0.35 - 0.43 in.)
C MA 10.5 - 12 mm (0.413 - 0.47 in.)
MS 10 - 13 mm (0.39 - 0.51 in.)
(Reference)
Using SST, check the drive belt tension.
SST A 09216-00020
SST B 09216-00030
Drive belt tension:
New belt A 70 - 80 kg
B 65 - 65 kg
C 53 - 77 kg
Used belt A 30 - 45 kg
B 25 - 40 kg
C 30 - 40 kg
NOTE:
0 “New belt” refers to a belt which has been used less
than 5 minutes on a running engine.
0 “Used belt” refers to a belt which has been used on a
running engine for 5 minutes or more.
0 After installing the drive belt, check that it fits properly
in the ribbed grooves. l Check by hand to confirm that the belt has not slipped
out of the groove on the bottom of the crank pulley.
l After installing the belt, run the engine for approx. 5
minutes and then recheck the deflection.