Isuzu Trooper (1998-2002 year). Manual - part 550

6A – 8 ENGINE MECHANICAL

Parts

Items

Service standard

Service limit

Remarks

Cylinder 
Block

—

95.421 – 95.450
(3.7567 – 3.7579)

0.20 (0.0079)

Warpage
(Upper surface of the cylinder block)

Cylinder bore diameter

Parts

Items

Service standard

Service limit

Remarks

Thermostat

Radiator cap

83 – 87°C 
(181 – 189°F)

More than 9.5 (0.374)
at 100°C (212°F)

88.2 – 117.6 kPa
(12.8 –17.0 psi)

Valve opening temperature

Valve full open temperature and lift

Valve opening pressure

Engine Cooling

mm (in)

mm (in)

ENGINE MECHANICAL 6A – 9

SERVICING

Servicing refers to general maintenance procedures to
be performed by qualified service personnel.

MODEL IDENTIFICATION

Engine Serial Number

The engine number is stamped on the rear left hand
side of the cylinder body.

AIR CLEANER

Oil Wetted (Viscous) Type Paper Element.

The air cleaner has an oil wetted paper element. No
servicing is required until the replacement interval is
reached.
Never attempt to clean the element, no matter how dirty
it may appear. The element is designed to provide
normal filtering efficiency until it becomes due for
replacement.
Refer to the Item “Service and Maintenance” in the
Owner’s and Driver’s Manual for general service
information.

LUBRICATING SYSTEM

Main Oil Filter (Cartridge Type Paper Element)

Replacement Procedure

1. Loosen the drain plug to drain the engine oil.
2. Wait a few minutes and then retighten the drain

plug.

3. Loosen the used oil filter (2) by turning it counter-

clockwise with the filter wrench.

4. Clean the oil filer gasket fitting face.

This will allow the new oil filter to seat properly.

5. Apply a light coat of engine oil to the O-ring.
6. Turn the new oil filter until the filter O-ring is fitted

against the sealing face.

7. Use the filter wrench to turn the filter additional one

and 1/4 turns.
Filter Wrench: 5-5540-0203-0

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6A – 10 ENGINE MECHANICAL

8. Check the engine oil level and replenish to the

specified level if required.

9. Start the engine and check for oil leakage from the

main oil filter.

FUEL SYSTEM

Fuel filter

Replacement Procedure

1. Loosen the used fuel filter by turning it

counterclockwise with the filter wrench.
Filter Wrench : 5-8840-0203-0

2. Clean the filter cover fitting faces.

This will allow the new fuel filter to seat properly.

3. Apply a light coat of engine oil to the O-ring.
4. Turn the fuel filter until the sealing face comes in

contact with the O-ring.

5. Turn the fuel filter with a filter wrench 2/3 of a turn

until sealed.
Filter Wrench: 5-8840-0203-0

Legend

(1) Priming pump

6. Operate the priming pump until the air is discharged

completely from fuel system.

NOTE: The use of an Isuzu genuine fuel filter is
strongly recommended.

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.

NOTE: Do not overfill the reserve tank.

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ENGINE MECHANICAL 6A – 11

Remove the radiator filler cap only when absolutely
necessary.
Always check the coolant level when the engine is cold.
Always refer to the chart at the left to determine the
correct cooling water to antifreeze solution mixing ratio.

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: 196 kPa (2 kg/cm

2

/28.45 psi)

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

/15 psi).

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 Filler Cap Pressure Valve: 88.2 – 117.6 kPa 
(0.899 – 1.199 kg/cm

2

/12.8 – 17.1 psi)

Negative Valve (Reference): 1.0 – 3.9 kPa 
(0.01 – 0.04 kg/cm

2

/0.14 – 0.57 psi)

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: 

83 – 87°C (181 – 189°F)

4. Check the thermostat full opening temperature.

Thermostat Full Opening Temperature: 

100°C (212°F)

Valve Lift at Fully Open Position: 9.5 mm (0.374
in)

0

-10

-20

-30

-40

-50

-60

10

20

30

Mixing ratio (%)

F

reezing point  ( 

°

C)

40

50

60

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