engine ISUZU KB P190 2007 Workshop Repair Manual

ENGINE COOLING (4JK1/4JJ1) 6B-3
General Description
Coolant Flow








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The engine cooling system consists of the radiator, the
water pump, the cooling fan, and the thermostat.
To quickly increase cold engine coolant temperature fo
r
smooth engine operation, the coolant is circulated by
the water pump and thermostat through the bypass pipe
and back to the cylinder body.
The coolant does not circulate through the radiator.
W hen the coolant temperature reaches the specified
value, the thermostat will begin to open and a graduall
y
increasing amount of coolant will circulate through the
radiator.
The thermostat will be fully open when the coolant
temperature reaches the specified value. All of the
coolant is now circulating through the radiator fo
r
effective engine cooling.


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6B-4 ENGINE COOLING (4JK1/4JJ1)
Water Pump




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A centrifugal type water pump forcefully circulates the
coolant through the cooling system.

The water pump is not a disassembled type.
Thermostat





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A wax pellet type thermostat is used.


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ENGINE COOLING (4JK1/4JJ1) 6B-5
Radiator
The radiator is a tube type with corrugated fins. In order
to raise the boiling point of the coolant, the radiator is
fitted with a cap in which the valve is operated at 93.3 -
122.7 kPa (0.95 - 1.25 kg / cm
2 / 13.5 - 17.8 psi)
pressure. (No oil cooler provided for M/T)




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Antifreeze Solution
NOTE:
Antifreeze solution + W ater = Total cooling system
capacity.
Total Cooling System Capacity Lit
(US / UK gal) (US pint)
M/T 8.7 (2.3/1.9) (18.4)
A/T 8.6 (2.3/1.9) (18.2)
See section 0B MAINTENANCE AND LUBRICATION .







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NOTE:
To maintain the corrosion resistance of the aluminum
radiator, water and antifreeze must be combined in a
1:1 solution (50% antifreeze and 50% water).



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6B-6 ENGINE COOLING (4JK1/4JJ1)
Diagnosis
Engine Cooling Trouble
Condition Possible Cause Correction
Low Engine Coolant level Replenish
Thermo meter unit faulty Replace
Faulty thermostat Replace
Faulty Engine Coolant temperature
sensor Repair or replace
Clogged radiator
Clean or replace
Faulty radiator cap Replace
Low engine oil level or use of
improper engine oil Replenish or change oil
Clogged exhaust system
Clean exhaust system or replace
faulty parts
Faulty Throttle Position sensor Replace throttle valve assembly
Open or shorted Throttle Position
sensor circuit Repair or replace
Engine overheating
Damaged cylinder head gasket Replace
Engine overcooling Faulty thermostat Replace
Faulty thermostat Replace Engine slow to warm–up
Thermo unit faulty Replace


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ENGINE COOLING (4JK1/4JJ1) 6B-7
Draining and Refilling Cooling System
Before draining the cooling system, inspect the system
and perform any necessary service to ensure that it is
clean, does not leak and is in proper working order.
The engine coolant (EC) level should be between the
“MIN" and “MAX" lines of the reserve tank when the
engine is cold. If low, check for leakage and add EC up
to the “MAX" line.
There should not be any excessive deposit of rust o
r
scales around the radiator cap or radiator filler hole, and
the EC should also be free from oil.
Replace the EC if excessively dirty.

1. Remove the radiator skid plate.
2. Completely drain the cooling system by opening the drain plug at the bottom of the radiator.




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3. Remove the radiator cap.
WARNING:
To avoid the danger of being burned, do not
remove the cap while the engine and radiator are
still hot. Scalding fluid and steam can be blown out
under pressure.
4. Disconnect all hoses from the EC reserve tank.
Scrub and clean the inside of the reserve tank with soap and water. Flush it well with clean water,
then drain it. Install the reserve tank and hoses.

5. Refill the cooling system with the EC using a
solution that is at least 50 percent antifreeze.

Procedure for filling with coolant (in case of full change).
• Make sure that the engine is cool.
• Open radiator cap and pour coolant up to fille
r
neck.
• Pour coolant into reservoir tank up to “MAX" line.
• Tighten radiator cap and start the engine. Afte
r
idling for 2 to 3 minutes, stop the engine and
reopen the radiator cap. If the water level is lower,
replenish.
WARNING:
When the coolant is heated to a high temperature,
be sure not to loosen or remove the radiator cap.
Otherwise you might get scalded by hot vapor o
r
boiling water. To open the radiator cap, put a piece
of thick cloth on the cap and loosen the cap slowly
to reduce the pressure when the coolant has
become cooler.
• After tightening the radiator cap, warm up the
engine at about 2000 rpm. Set heater adjustment
to the highest temperature position, and let the
coolant circulate also into heater water system.
• Check to see the thermostat has opened through
the needle position of the water thermometer,
conduct a 5–minute idling again and stop the
engine.
• W hen the engine has been cooled, check fille
r
neck for water level and replenish if required.
Should extreme shortage of coolant be found,
check the cooling system and reservoir tank hose
for leakage.
• Pour coolant into the reservoir tank up to “MAX"
line.

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6B-8 ENGINE COOLING (4JK1/4JJ1)
Water Pump
Read this Section carefully before performing any
removal and installation procedure. This Section gives
you important points as well as the order of operation.
Be sure that you understand everything in this Section
before you begin.

Removal
1. Remove the engine cover.
2. Radiator Upper Hose a. Partially drain the engine coolant.
b. Remove the radiator upper hose.






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3. W ater Outlet Pipe
a. Disconnect the turbocharger-cooling pipe from the outlet pipe.
b. Loosen the fixing bolt and remove the wate
r
outlet bolt.
4. Upper Fan Shroud
5. Fan and Fan Clutch a. Loosen the fan clutch nuts.
b. Remove the fan together with the fan clutch. Take care not to damage the radiator core.
6. Fan Drive Belt and Pulley a. Loosen the tension adjust bolt on the generator.
b. Remove the fan drive belt with the fan pulley.






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7. W ater Pump
a. Remove the water pump bolts and nuts.
b. Remove the water pump.





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ENGINE COOLING (4JK1/4JJ1) 6B-9
Inspection and Repair
The water pump is not disassembled type.
Make necessary parts replacement if extreme wear o
r
damage is found during inspection. Should any of the
following problems occur, the entire water pump
assembly must be replaced.
• Cracks in the water pump body.
• Coolant leakage from the sealed unit.
• Excessive radial play or abnormal noise in the fan
center when rotated by hand.
• Excessive thrust play in the fan center (Standard
play: less than 0.2 mm (0.0078 in)).
• Cracks or corrosion in the impeller.
Installation
1. W ater Pump





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a. Install the water pump with a new gasket.
b. Tighten bolts and nuts to specified torque.
Water Pump Nut/Bolt Torque: 25 N·m (2.5 kg·m /18 lb ft)

2. Fan Drive Belt and Pulley and Fan and Fan Clutch.






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a. Install the fan drive belt and fan pulley and fan
and fan clutch.
b. Tighten the nuts to specified torque.
Fan Clutch Nut Torque: 8 N·m (0.8 kg·m /69 lb in) c. Apply tension to the fan drive belt by moving the generator.
d. Apply a force of 98 N (10 kg/22 lb) to the drive belt mid-portion to check the drive belt
deflection.
Fan Drive Belt Deflection mm (in)
New belt 5 - 6 (0.20 – 0.24)
Reuse belt 7 - 8 (0.28 – 0.32)
3. Upper Fan Shroud
4. W ater Outlet Pipe.
a. Install the water outlet pipe to the thermostat housing.
b. Tighten the outlet pipe bolt to specified torque.
Outlet Pipe Bolt Torque: 25 N·m (2.5 kg·m /18 lb ft)
c. Connect the turbocharger-cooling pipe to outlet pipe.

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6B-10 ENGINE COOLING (4JK1/4JJ1)
5. Radiator Upper Hose.






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a. Connect the radiator upper hose to the water
outlet pipe.
b. The knob of clamp shall be directed to horizontal.
c. Replenish the engine coolant.
6. Install the engine cover.


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ENGINE COOLING (4JK1/4JJ1) 6B-11
Thermostat
Read this Section carefully before performing any
removal and installation procedure. This Section gives
you important points as well as the order of operation.
Be sure that you understand everything in this Section
before you begin.

Removal
1. Remove the engine cover.
2. Radiator Upper Hose a. Partially drain the engine coolant.
b. Remove the radiator upper hose.
c. Remove the engine harness clip.






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3. W ater Outlet Pipe
a. Disconnect the turbocharger-cooling pipe from outlet pipe.
b. Loosen the fixing bolt and remove the wate
r
outlet bolt.
4. Thermostat
Remove the thermostat from the thermostat housing.
Take care not to damage the thermostat.




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Legend
1. Front
2. Thermostat
3. Jiggle Valve

Inspection and Repair
Make the necessary adjustments, repairs, and part
replacements if excessive wear or damage is
discovered during inspection.
Operating Test of Thermostat
1. Completely submerge the thermostat in water.
2. Heat the water.Stir the water constantly to avoid direct heat being applied to the thermostat.
3. Check the thermostat initial opening temperature.
Thermostat Initial Opening Temperature °C (°F)
85 (185)
4. Check the thermostat full opening temperature.
Thermostat Full Opening Temperature °C (°F)
100 (212)
Valve Lift At Fully Open Position mm (in)
10 (0.39)


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6B-12 ENGINE COOLING (4JK1/4JJ1)







MFW 41CSH001401
Legend
1. W ooden Piece
2. Agitating Rod

Installation
1. Thermostat
Install the thermostat.
Mount the jiggle valve with the valve facing engine front.




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Legend
1. Front
2. Thermostat
3. Jiggle Valve


2. W ater Outlet Pipe.
a. Install the water outlet pipe with new gasket to the thermostat housing.
b. Tighten the outlet pipe bolt to specified torque.
Outlet Pipe Bolt Torque: 25 N·m (2.5 kg·m /18 lb ft)
c. Connect the turbocharger-cooling pipe to outlet pipe.
d. Install the engine harness clip.
3. Radiator Upper Hose.






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a. Connect the radiator upper hose to the water
outlet pipe.
b. The knob of the clamp should be directed to the horizontal side.
c. Replenish the engine coolant.
4. Install the engine cover.

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