Isuzu KB P190. Service manual — part 208

ENGINE MECHANICAL 6A – 27

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COOLING SYSTEM

Coolant Level

Check the coolant level and replenish the radiator reserve
tank as necessary.

If the coolant level falls below the “MIN” line, carefully
check the cooling system for leakage. Then add enough
coolant to bring the level up to the “MAX” line.

Engine coolant Filling up procedure

1. Make sure that the engine is cool.

Warning:

When the coolant is heated to a high temperature, be
sure not to loosen or remove the rediator cap.
Otherwise you might get scalded by hot vapor or
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.

2. Open rediator cap pour coolant up to filler neck

3. Pour coolant into reservoir tank up to “MAX” line

4. Tighten radiator cap and start the engine. After idling

for 2 to 3 minutes, stop the engine and reopen radiator
cap. If the water level is lower, replenish.

5. After replenish the coolant tighten 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.

6. Check to see the thermometer, continuously idling 5

minutes and stop the engine.

7. When the engine has been cooled, check filler neck

for water level and replenish if required. Should
extreme shortage of coolant is found, check the
coolant system and reservoir tank hose for leakage.

8. Pour coolant into the reservoir tank up to “MAX” line.

Engine Coolant Total Capacity

Lit (U.S / UK gal)

4JA1 / TC

9.4 (2.5 / 2.1)

4JH1TC

M/T: 10.1 (2.7 / 2.2)

A/T: 10.0 (2.6 / 2.2)

Mixing Ratio (Anti-Freeze Solution/Water)

50 %

6A – 28 ENGINE MECHANICAL

Cooling System Inspection

Install a radiator filler cap tester to the radiator. Apply
testing pressure to the cooling system to check for
leakage. The testing pressure must not exceed the
specified pressure.

Testing Pressure

kPa(kg/cm

2

/psi)

150 (1.5/21)

Radiator Cap Inspection

The radiator filler cap is designed to maintain coolant
pressure in the cooling system at 103 kPa(1.05 kg/cm

2

,

15psi).

Check the radiator filler cap with a radiator filler cap tester.
The radiator filler cap must be replaced if it fails to hold the
specified pressure during the test procedure.

Radiator Cap Valve Opening Pressure
kPa(kg/cm

2

/psi)

90 – 120 (0.9 – 1.2/13 – 17)

Negative Valve (Reference)

kPa(kg/cm

2

/psi)

1.9 – 4.9 (0.02 – 0.05/0.28 – 0.71)

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ENGINE MECHANICAL 6A – 29

Thermostat Operating Test

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)

82 (180)

Oil Cooler Thermo Valve

°C (°F)

76.5 (170)

EGR Cooler Thermo Valve

°C (°F)

40 (104)

4. Check the thermostat full opening temperature.

Thermostat Full Opening Temperature

°C (°F)

95 (203)

Oil Cooler Thermo Valve

°C (°F)

90 (194)

EGR Cooler Thermo Valve

°C (°F)

55 (131)

Valve Lift at Fully Open position

mm (in)

9.5 (0.37)

Oil Cooler Thermo Valve

mm (in)

4.5 (0.18)

EGR Cooler Thermo Valve

mm in)

3.5 (0.14)

Drive Belt Adjustment

Check drive belts for wear or damage, and replace with
new ones as necessary. Check belts for tension, and
adjust as necessary.

1 Crankshaft damper pulley

2 Generator pulley

3 Cooling fan pulley

4 Oil pump pulley or idler pulley

5 Compressor pulley or idler pulley

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6A – 30 ENGINE MECHANICAL

Cooling Fan Pulley Drive Belt

Fan belt tension is adjusted by moving the generator.

Depress the drive belt mid-portion with a 98N (10 kg/22 lb)
force.

Cooling Fan Drive Belt Deflection

mm (in)

New belt 4 - 7 (0.16 - 0.28)
Reuse belt 6 - 9 (0.24 - 0.35)

1 Crankshaft damper pulley

2 Generator pulley

3 Cooling fan pulley

A/C Compressor Drive Belt

Compressor belt tension is adjusted by moving the P/S
pumppulley.

Depress the drive belt mid-portion with a 98N (10 kg/22 Ib)

force.

A/C Compressor Drive Belt Deflection

mm (in)

New belt 9 - 10 (0.35 - 0.39)
Reuse belt 12 - 13 (0.47 - 0.51)

1 Crankshaft damper pulley

2 P/S pump pulley

2 A/C Compressor pulley

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