2007 ISUZU KB P190 engine

6B-4 ENGINE COOLING

Antifreeze Solution
• Calculating mixing ratio
Mixing ratio

= Antifreeze solution (Lit/gal.)
Antifreeze solution (Lit/gal.) + W ater (Lit/gal.)

NOTE: Antifreeze solution + W ater = Total cooling system
capacity.
• Total Cooling System Capacity
8Lit


• Mixing ratio
Check the specific gravity of engine coolant in the cooling system temperature ranges from 0 °C to 50 °C using a
suction type hydrometer, then determine the density of the
engine coolant by referring to the table.

NOTE: The LLC is 50% at all environment in order to prevent
the corrosion of cooling system parts.


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ISUZU KB P190 2007

ENGINE COOLING 6B-5
Diagnosis
Engine Cooling Trouble
Condition Possible cause Correction
Engine overheating Low Engine Coolant level Replenish
Thermo mater 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

Damaged cylinder head gasket Replace
Loosen V-belt tension Adjust belt tension or replace.
Collapsed hoses Replace
Faulty Fan clutch Replace
Engine overcooling Faulty thermostat Replace
Engine slow to warm-up Faulty thermostat Replace
Thermo unit faulty Replace


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ISUZU KB P190 2007

6B-6 ENGINE COOLING

















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
level should be between the "MIN" and "MAX" lines of reserve
tank when the engine is cold. If low, check for leakage and add
engine coolant up to the "MAX" line. There should not be any
excessive deposit of rust or scales around the radiator cap or
radiator filler hole, and the engine coolant should also be free
from oil.
Replace the engine coolant if excessively dirty.
1. Completely drain the cooling system by opening the drain
plug at the bottom of the radiator.
2. 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.
3. Disconnect all hoses from the engine coolant 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.
4. Refill the cooling system with the engine coolant using a solution that is at least 50 percent antifreeze.
5. Fill the radiator to the base of the filler neck.
Fill the engine coolant reserve tank to "MAX" line when the engine is cold.
6. Block the drive wheels and firmly apply the parking brake and place the shift lever in the "NEUTRAL" position.
7. Remove the radiator cap. Start the engine and warm it up at 2,500 - 3,000 rpm for about 30 minutes.
8. W hen the air comes out from the radiator filler neck and the engine coolant level has gone down, replenish with the
engine coolant. Repeat this procedure until the engine
coolant level does not go down. Then stop the engine and
install the radiator cap. Let the engine cool down.
9. After the engine has cooled, replenish with engine coolant up to the "MAX" line of the reserve tank.
10. Start the engine. W ith the engine running at 3,000 rpm, make sure there is no running water sound from the heate
r
core (behind the center console).
11. If the running water sound is heard, repeat steps 8 to 10.


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ISUZU KB P190 2007

ENGINE COOLING 6B-7
Water Pump
Water Pump and Associated Parts








Legend
1 Water Pump Assembly 2 O-Ring
3 Bolt

2
3 1

















Removal
1. Disconnect battery ground cable.
2. Drain coolant.
3. Disconnect radiator hose (on inlet pipe side).
4. Remove timing belt, refer to "Timing Belt" in this manual.
5. Remove water pump assembly.
Inspection
Make necessary repair and parts replacement if extreme wear
or damage is found during inspection. Should any of the
following problems occur, the entire water pump assembly
must be replaced:

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6B-8 ENGINE COOLING










•
Crack in the water pump body
• EC leakage from the seal unit
• Play or abnormal noise in the bearing
• Cracks or corrosion in the impeller
Installation
1. Before installing water pump, coat sealing surface with
silicon grease.
2. Install water pump assembly and tighten bolts to the specified torque.
Torque: 25 N ⋅
⋅⋅
⋅
m (2.5 kgf ⋅
⋅⋅
⋅
m)
3. Timing belt • Install timing belt, refer to timing belt installation step in
"Timing Belt" in this manual.
4. Connect radiator hose and replenish EC.
5. Connect battery ground cable.


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ISUZU KB P190 2007

ENGINE COOLING 6B-9
Thermostat





























Removal
1. Disconnect battery ground cable.
2. Drain engine coolant from the radiator and engine.
3. Disconnect radiator hose from the inlet pipe.
4. Remove thermostat housing.
5. Remove thermostat from thermostat housing.
Inspection
Suspend the thermostat in a water-filled container using thin
wire. Place a thermometer next to the thermostat.
Do not directly heat the thermostat.
Gradually increase the water temperature. Stir the water so
that the entire water is same temperature.
Confirm the temperature when the valve first begins to open.
Valve opening temperature 92 °
°°
°
C (197.6 °
°°
°
F)
Confirm the temperature when the valve is fully opened.
Valve full open temperature 107 °
°°
°
C(224.6 °
°°
°
F)
Make necessary repair and parts replacement if extreme wear
or damage is found during inspection.
Installation
1. Before installing thermostat, coat sealing surface with
silicon grease.
2. Install O-ring.
3. Install thermostat housing and tighten bolts to the specified torque.
Torque: 15 N ⋅
⋅⋅
⋅
m (1.5 kgf ⋅
⋅⋅
⋅
m)
4. Installation rubber hose.
5. Replenish engine coolant (EC).
6. Start engine and check for EC leakage.













Fan Clutch with Cooling Fan
Inspection and Repair
Make necessary correction or parts replacement if wear,
damage or any other abnormal condition are found through
inspection.

Visually inspect for damage, leak (silicon grease) or other
abnormal conditions.
1. Inspection (on-vehicle)
1) Turn the fan clutch by hand when in a low temperature condition before starting the engine, and confirm that it
can be turned readily.
2) Start the engine to warm it up until the temperature at the fan clutch portion gets to around 80 °C. Then stop the
engine and confirm that the fan clutch can be turned with
considerable effort (clutch torque) when turned by hand.


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ISUZU KB P190 2007

6B-10 ENGINE COOLING
If the fan clutch rotates more readily, however, this indicates that the silicon grease is leaking internally.
Replace the fan clutch with a new one.

2. Inspection (in unit)
W arm up the bimetal of the fan clutch by using the heat gun until the temperature gets to about 80 °C when measured
with the thermistor. Then confirm that the fan clutch can be
turned with considerable effort (clutch torque).
If the fan clutch retates more readily at this time, this indicates that the silicon grease is leaking internally.
Replace the fan clutch with a new one.


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ISUZU KB P190 2007

ENGINE COOLING 6B-11
Radiator
Radiator and Associated Parts



Legend
1 Radiator Hose
2 Drain Plug
3 Fan Guide, Lower
4 Fan Guide
5 Bracket 6 Reserve Tank Hose
7 Reserve Tank
8 Radiator Cap
9 Radiator Assembly


Removal
1. Disconnect battery ground cable.
2. Loosen a drain plug to drain engine coolant (EC).
3. Disconnect radiator inlet hose and outlet hose.
4. Disconnect the reserve tank hose from radiator.
5. Lift out the radiator assembly, taking care not to damage the radiator core.


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ISUZU KB P190 2007