6-24 ENGINE GENERAL INFORMATION AND DIAGNOSIS (TBI FOR G10)
ConditionPossible CauseReferring Item
OverheatingInoperative thermostat
Poor water pump performance
Clogged or leaky radiator
Improper engine oil grade
Clogged oil filter or oil strainer
Poor oil pump performance
Faulty radiator fan control system
Dragging brakes
Slipping clutch
Blown cylinder head gasketThermostat in Section 6B
Water pump in Section 6B
Radiator in Section 6B
Engine oil and oil filter change in
Section 0B
Oil pressure check in Section 6A
Oil pressure check in Section 6A
Radiator fan control system in
Section 6E1
Trouble diagnosis in Section 5
Trouble diagnosis in Section 7C
Cylinder head in Section 6A
Poor gasoline
mileageIgnition system out of order
Leaks or loose connection of high-tension cord
Faulty spark plug (improper gap, heavy deposits
and burned electrodes, etc.)
Engine and emission control system out of
order
High idle speed
Poor performance of TP sensor, ECT sensor or
MAP sensor
Faulty fuel injector
Faulty fuel injector resistor
Faulty ECM (PCM)
Low compression
Others
Poor valve seating
Dragging brakes
Slipping clutch
Thermostat out of order
Improper tire pressure
High-tension cords in Section 6F
Spark plugs in Section 6F
Refer to item “Improper engine
idle speed” previously outlined
TP sensor, ECT sensor or MAP
sensor in Section 6E1
Diagnostic Flow Table B-1
Fuel injector resistor in Section 6E1
Previously outlined
Valves inspection in Section 6A
Trouble diagnosis in Section 5
Trouble diagnosis in Section 7C
Thermostat in Section 6B
Refer to Section 3F
Excessive engine
oil consumptionOil leakage
Blown cylinder head gasket
Leaky camshaft oil seals
Oil entering combustion chamber
Sticky piston ring
Worn piston and cylinder
Worn piston ring groove and ring
Improper location of piston ring gap
Worn or damaged valve stem seal
Worn valve stem
Cylinder head in Section 6A
Camshaft in Section 6A
Piston cleaning in Section 6A
Pistons and cylinders inspection
in Section 6A
Pistons inspection in Section 6A
Pistons assembly in Section 6A
Valves removal and installation in
Section 6A
Valves inspection in Section 6A
6-1-24 ENGINE GENERAL INFORMATION AND DIAGNOSIS (SFI FOR G13)
ConditionPossible CauseReferring Item
OverheatingInoperative thermostat
Poor water pump performance
Clogged or leaky radiator
Improper engine oil grade
Clogged oil filter or oil strainer
Poor oil pump performance
Faulty radiator fan control system
Dragging brakes
Slipping clutch
Blown cylinder head gasketThermostat in Section 6B
Water pump in Section 6B
Radiator in Section 6B
Engine oil and oil filter change in
Section 0B
Oil pressure check in Section 6A1
Oil pressure check in Section 6A1
Radiator fan control system in
Section 6E2
Trouble diagnosis in Section 5
Trouble diagnosis in Section 7C
Cylinder head in Section 6A1
Poor gasoline
mileageIgnition system out of order
Leaks or loose connection of high-tension cord
Faulty spark plug (improper gap, heavy deposits
and burned electrodes, etc.)
Engine and emission control system out of
order
Malfunctioning EGR valve
High idle speed
Poor performance of TP sensor, ECT sensor or
MAP sensor
Faulty EGR valve
Faulty fuel injector(s)
Faulty ECM (PCM)
Low compression
Others
Poor valve seating
Dragging brakes
Slipping clutch
Thermostat out of order
Improper tire pressure
High-tension cords in Section 6F1
Spark plugs in Section 6F1
EGR system in Section 6E2
Refer to item “Improper engine
idle speed” previously outlined
TP sensor, ECT sensor or MAP
sensor in Section 6E2
EGR system in Section 6E2
Diagnostic Flow Table B-1
Previously outlined
Valves inspection in Section 6A1
Trouble diagnosis in Section 5
Trouble diagnosis in Section 7C
Thermostat in Section 6B
Refer to Section 3F
Excessive engine
oil consumptionOil leakage
Blown cylinder head gasket
Leaky camshaft oil seals
Oil entering combustion chamber
Sticky piston ring
Worn piston and cylinder
Worn piston ring groove and ring
Improper location of piston ring gap
Worn or damaged valve stem seal
Worn valve stem
Cylinder head in Section 6A1
Camshaft in Section 6A1
Piston cleaning in Section 6A1
Pistons and cylinders inspection
in Section 6A1
Pistons inspection in Section 6A1
Pistons assembly in Section 6A1
Valves removal and installation in
Section 6A1
Valves inspection in Section 6A1
1
2
6A1-64 ENGINE MECHANICAL (G13B, 1-CAM 16-VALVES ENGINE)
UNIT REPAIR OVERHAUL
ENGINE ASSEMBLY
REMOVAL
1) Release fuel pressure in fuel feed line by referring to Section
6.
2) Remove battery.
3) Remove engine hood after disconnecting windshield washer
hose.
4) Drain cooling system.
WARNING:
To help avoid danger of being burned, do not remove
drain plug (2) and radiator cap while engine and radiator
(1) are still hot. Scalding fluid and steam can be blown
out under pressure if plug and cap are taken off too
soon.
5) Disconnect coupler of cooling fan motor.
6) Disconnect radiator inlet hose from thermostat case.
7) Disconnect A / T fluid hoses from A / T fluid pipes (for A / T mod-
el)
8) Remove outlet hose from water inlet pipe and radiator.
9) Remove radiator referring to Section 6B.
10) Remove air cleaner case and air cleaner outlet hose as pre-
viously outlined.
11) Disconnect the following cables.
Accelerator cable (1) from throttle body.
A / T throttle pressure control cable from A / T.
Clutch cable from transmission (M / T).
Gear select cable from transmission (A / T).
Speedometer cable
6B
ENGINE COOLING 6B-1
SECTION 6B
ENGINE COOLING
NOTE:
For the descriptions (items) not found in this section, refer to the same section of Service Manual men-
tioned in FOREWORD of this manual.
CONTENTS
GENERAL DESCRIPTION6B-2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
DIAGNOSIS6B-4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
MAINTENANCE6B-5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Coolant6B-5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Cooling System Flush and Refill 6B-6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
ON-VEHICLE SERVICE6B-7 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Coolant Water Pipes or Hoses6B-7 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Thermostat6B-7 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Water Pump6B-9 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
8. Heater inlet hose
9. Heater outlet hose
10. Radiator
11. Oil cooler (A / T only)
12. Engine
13. ECT sensor1. Radiator inlet hose
2. Radiator outlet hose
3. Water intake pipe
4. Thermostat
5. Water pump
6. IAC valve (throttle body)
7. Breather pipe (air cleaner
outlet hose)
6B-2 ENGINE COOLING
GENERAL DESCRIPTION
COOLING SYSTEM CIRCULATION
During engine warm-up (thermostat closed), the water pump discharges coolant into the water jacket chamber
adjacent to No.1 cylinder. Coolant then flows through the cylinder block and the cylinder heat. Coolant then returns
to the water pump through intake manifold, heater inlet hose, heater unit, heater outlet hose, and water intake pipe.
During normal temperatures (thermostat open), coolant takes the same basic route but is now allowed to flow past
the thermostat, the inlet hose and the radiator, and then back to the water pump through the outlet hose and the
water intake pipe.
1. Cooling fan motor
2. Radiator
ENGINE COOLING 6B-3
THERMOSTAT
A wax pellet type thermostat is used in the coolant outlet passage
to control the flow of engine coolant, to provide fast engine warm
up and to regulate coolant temperatures.
A wax pellet element is hermetically contained in a metal case, and
expands when heated and contracts when cooled.
When the pellet is heated and expands, the metal case pushes
down the valve to open it.
As the pellet is cooled, the contraction allows the spring to close the
valve.
Thus, the valve remains closed while the coolant is cold, preventing
circulation of coolant through the radiator.
At this point, coolant is allowed to circulate only throughout the en-
gine to warm it quickly and evenly.
As the engine warms, the pellet expands and the thermostat valve
opens, permitting coolant to flow through the radiator.
In the top portion of the thermostat, an air bleed valve (1) is pro-
vided; this valve is for venting out the gas or air, if any, that is accu-
mulated in the circuit.
Thermostat functional spec. ± 2.8C (5.0F)
Temp. at which valve
begins to open88C (190F)
Temp. at which valve
become fully open100C (212F)
COOLING FAN
The cooling fan is driven by electric motor, and the motor is acti-
vated by ECM / PCM (engine coolant temp.). For its details, refer to
Section 6E.
WARNING:
Keep hands, tools, and clothing away from engine cooling
fan to help prevent personal injury. This fan is electric and
can come on whether or not the engine is running. The fan
can start automatically in response to the ECM / PCM (en-
gine coolant temp.) with the ignition switch in the “ON”
position.
6B-4 ENGINE COOLING
COOLANT (WATER) TEMP. GAUGE
The coolant temp. gauge is included in engine coolant temp. (ECT)
sensor (1). This gauge activates a temp. meter in the instrument
cluster.
DIAGNOSIS
ConditionPossible CauseCorrection
Engine overheatsLoose or broken water pump belt
Not enough coolant
Faulty thermostat
Faulty water pump
Dirty or bent radiator fins
Coolant leakage on cooling system
Defective cooling fan motor
Plugged radiator
Faulty radiator cap
Maladjusted ignition timing
Dragging brakes
Slipping clutchAdjust or replace.
Check coolant level and add as
necessary.
Replace.
Replace.
Clean or remedy.
Repair.
Check and replace as
necessary.
Check and replace radiator as
necessary.
Replace.
Adjust.
Adjust brake.
Adjust or replace.
2. Outlet hose
6B-6 ENGINE COOLING
COOLING SYSTEM FLUSH AND REFILL
WARNING:
To help avoid danger of being burned, do not remove radia-
tor cap while engine and radiator cap while engine and ra-
diator are still hot. Scalding fluid and steam can be blown
out under pressure if cap is taken off too soon.
1) Remove radiator cap when engine is cool:
Turn cap counterclockwise slowly until it reaches a “stop”.
(Do not press down while turning it.)
Wait until pressure is relieved (indicated by a hissing sound)
then press down on cap and continue to turn it counterclock-
wise.
2) With radiator cap removed, run engine until upper radiator
hose is hot (this shows that thermostat is open and coolant is
flowing through system).
3) Stop engine and open radiator drain plug (1) to drain coolant.
4) Close drain plug. Add water until system is filled and run engine
until upper radiator hose is hot again.
5) Repeat Steps 3) and 4) several times until drained liquid is
nearly colorless.
6) Drain system and then close radiator drain plug tightly.
7) Disconnect reservoir tank hose from radiator. Remove reser-
voir tank and pour out any fluid. Scrub and clean inside of tank
with soap and water.
Flush it well with clean water and drain. Reinstall tank and
hose.
8) add 50 / 50 mixture of GOLDEN CRUISER 1200 (Good quality
ethylene glycol anti-freeze) and water to radiator and tank.
Fill radiator to the base of radiator filler neck and reservoir tank
to “FULL” level mark. Reinstall reservoir tank cap.
9) Run engine, with radiator cap removed, until radiator upper
hose is hot.
10) With engine idling, add coolant to radiator until level reaches
the bottom of filler neck. Install radiator cap, making sure that
the ear of cap lines up with reservoir tank hose.