Page 1742 of 6000

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
012RW115
012RW062
For Europe1
2
050R200001
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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: 5-8840-0203-0Legend
(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.
012RW112
012RW078
1
012RW111
012RW080
Page 1747 of 6000
6A – 14 ENGINE MECHANICAL
TIGHTENING TORQUE
Timing Gear Case, Timing Gear
Nꞏm (kgꞏm/lbꞏft)
75(7.6/55)
Apply engine oil to
thread and seat 8(0.8/6)
20(2.0/14.5)
51(5.2/38)
25(2.5/18)
020RW00001
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6A – 42 ENGINE MECHANICAL
2. Cylinder head for cracks, especially between valve
seats and in the exhaust ports.
3. Cylinder head deck for corrosion, sand particles in
head and porosity.
CAUTION: Do not attempt to weld the cylinder
head. Replace it.
4. Cylinder head lower surface for flatness.
Use a straight edge and a feeler gauge to measure
the cylinder head lower surface warpage.
If the measured values exceed the specified limit,
the cylinder head must be replaced.
Cylinder Head Lower Face Warpage:
Standard: 0.075 mm (0.0029 in) or less
Limit: 0.2 mm (0.0079 in)
Cylinder Head Height:
Standard: 95 mm (3.740 in)
5. Water jacket sealing plugs seating surfaces.
6. Use a straight edge and a feeler gauge to measure
the manifold cylinder head fitting face warpage.
If the measured values exceed the specified limit,
the manifold must be replaced.
Exhaust Manifold Warpage:
Standard: 0.05 mm (0.0020 in) or less
Limit: 0.20 mm (0.0079 in)
CAUTION: Do not attempt to weld the cylinder
head. Replace it.
REASSEMBLY
1. Cylinder Head
Refer to “Cylinder Head Gasket”.
2. Glow Plug and Glow Plug Connector
Tighten glow plugs.
Torque: 15 Nꞏm (1.5 kgꞏm/11 lb ft)
011RW006
012RW053
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6A – 60 ENGINE MECHANICAL
VALVE STEM SEAL, VALVE SPRING AND ADJUSTER
REMOVAL
1. Disconnect battery ground cable.
2. Drain engine coolant.
3. Remove the air duct from between air cleaner and
turbocharger.
4. Remove intercooler assembly.
Refer to “Intercooler” in this manual.
5. Remove oil level gauge guide assembly.
6. Disconnect PCV hose.
7. Disconnect EGR vacuum hose.
8. Disconnect harness connectors around the cylinder
head such as the injector, CMP sensor, MAP
sensor, EGR sensor, EVRV, IAT sensor, A/C
compressor, TP stepping motor, TP sensor and fuel
temperature sensor etc.
9. Remove A/C compressor assembly.
10. Remove A/C compressor bracket.
11. Remove generator assembly and take out drivebelt.
12. Remove heat protector, remove exhaust valve
assembly.
13. Remove water cooling hose and lubrication pipe for
turbocharger.
14. Remove turbocharger assembly.
15. Remove hose between thermostat and radiator.
16. Remove noise insulator cover of cylinder head.
NOTE: Do not damage injector harness.
17. Remove high pressure oil pipe.
18. Remove timing belt cover.
19. Remove CMP sensor bracket.
20. Remove timing belt tensioner then remove timing
belt.
21. Remove camshaft pulley.
22. Remove front plate.
23. Remove engine coolant pipe between cylinder
head and water pump.
1
2
3
4
5
6
9
10
7
8
011RW031
Legend
(1) Adjuster
(2) Tappet
(3) Split Collar
(4) Spring Seat Upper
(5) Valve Spring(6) Spring Seat Lower
(7) Valve Stem Seal
(8) Valve Guide
(9) Valve Seat
(10) Valve
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6A – 62 ENGINE MECHANICAL
3. Spring tension
1) Use a spring tester to compress the springs to
the installed height. Measure the compressed
spring tension.
2) Replace the springs if the measured tension is
below the specified limit.
Standard: 236.0 N (24 kg/53 lb)
Limit: 205.0 N (21 kg/46 lb)Va l v e G u i d e
CAUTION: Taking care not to damage the valve seat
contact surface, when removing carbon adhering to
the valve head.
Carefully inspect the valve stem for scratching or
abnormal wear. If these conditions are present, the
valve and the valve guide must be replaced as a set.
1. Valve Guide Clearance
1) Measure the valve stem diameter with a
micrometer.
If the valve stem diameter is less than the
specified limit, the valve and the valve guide
must be replaced as a set.
Diameter of Valve stem:Inlet
Standard: 6.959 – 6.977 mm (0.2740 – 0.2747 in)
Limit: 6.92 mm (0.2724 in)
Diameter of Valve stem:Exhaust
Standard: 6.952 – 6.97 mm (0.2737 – 0.2744 in)
Limit: 6.90 mm (0.2717 in)
2) Measure the inside diameter of the valve guide
with a micrometer.
3) Subtract the measured outer diameter of the
valve stem from the measured inner diameter of
the valve guide.
If the valve exceeds the specified limit, the valve
and the valve guide must be replaced as a set.
Inlet clearance
Standard: 0.023 – 0.053 mm (0.0009 – 0.0021 in)
Limit: 0.19 mm (0.0075 in)
Exhaust clearance
Standard: 0.03 – 0.063 mm (0.0012 – 0.0025 in)
Limit: 0.20 mm (0.0079 in)
014RS006
014RS007
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ENGINE MECHANICAL 6A – 63
Valve Guide Replacement
1. Using the special tool, drive out the valve guide
from the combustion chamber side.
Valve guide replacer: 9-8523-1212-0
2. Apply engine oil to the outside of the valve guide.
Using the special tool, drive in a new valve guide
from cylinder head upper face side, and check the
valve guide height.
Valve guide replacer: 9-8523-1212-0
Height: 8.0 mm (0.315 in)
NOTE: If the valve guide has been removed, both the
valve and the valve guide must be replaced as a set.
Va l v e T h i c k n e s s
1. Measure the valve thickness.
2. If the measured value is less than the specified
limit, the valve and the valve guide must be
replaced as a set.
Inlet
Standard: 1.2 mm (0.0472 in)
Limit: 1.1 mm (0.0433 in)
Exhaust
Standard: 1.2 mm (0.0472 in)
Limit: 1.1 mm (0.0433 in)
Contact surface angle on valve seat on
valve
1. Measure contact surface angle on valve seat.
2. If the measured value exceeds the limit, replace
valve, valve guide and valve seat as a set.
Standard: 68°
011RW001
012RW052
012RW060
014RW018
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6A – 64 ENGINE MECHANICAL
Valve Depression
1. Measure the valve stem height from the upper
surface of the cylinder head as shown in the
illustration.
Standard:
Intake side 35.59 mm (1.4012 in)
Exhaust side 35.49 mm (1.3972 in)
Limit:
Intake side 35.74 mm (1.4071 in)
Exhaust side 35.64 mm (1.4031 in)
Legend
(1) Intake Side
(2) Exhaust Side
Valve Contact Width
1. Check the valve contact faces for roughness and
unevenness. Make the valve contact surfaces
smooth.
2. Measure the valve contact width.
If the measured value exceeds the specified limit,
the valve seat insert must be replaced.
Inlet
Standard: 2.1 mm (0.0827 in)
Limit: 2.6 mm (0.1024 in)
Exhaust
Standard: 2.0 mm (0.0787 in)
Limit: 2.5 mm (0.0984 in)
Valve Seat Insert Replacement
Valve Seat Insert Removal
1. Arc weld the entire inside circumference of the
valve seat insert.
2. Allow the valve seat insert to cool for a few minutes.
This will invite contraction and make removal of the
valve seat insert easier.
3. Use a screwdriver to pry the valve seat insert free.
Take care not to damage the cylinder head.
4. Carefully remove carbon and other foreign material
from the cylinder head insert bore.
12
011RW044
014RS015