1998 ISUZU TROOPER Cylinder head

SUPPLEMENTAL RESTRAINT SYSTEM STEERING WHEEL & COLUMN 2A – 85
5. Steering column cover
6. Combination switch
Disconnect the wiring harness connectors.
7. Snap ring
8. Cushion rubber
9. Shift lock cable (for A/T)
10. Lock cylinder assembly
Disconnect the starter switch harness connector
located under the steering column.
11. Steering column assembly
Apply a setting mark across the universal joint and
steering shaft to reassembly the parts in their original
position.
NOTE:
A setting mark can be easily made if the shaft is
withdrawn a little by loosening the steering shaft
universal joint. 3. Steering lower cover
Remove the engine hood opening lever.
4. Steering wheel
Apply a setting mark across the steering wheel and
shaft so parts can be reassembled in their original
position.
Use special tool. Remove the steering wheel.
Move the tires to the straight ahead positions before
removing the steering wheel.
Steering wheel remover:5-8840-0016-0(J-29752)

6A±1
ENGINE MECHANICAL
ENGINE
CONTENTS
Engine Mechanical 6A. . . . . . . . . . . . . . . . . . . . . .
Engine Cooling 6B. . . . . . . . . . . . . . . . . . . . . . . . .
Engine Fuel 6C. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Engine Electrical 6D1. . . . . . . . . . . . . . . . . . . . . . . .
Ignition System 6D2. . . . . . . . . . . . . . . . . . . . . . . . .
Starting and Charging System 6D3. . . . . . . . . . . . Driveability and Emissions 6E. . . . . . . . . . . . . . . .
Engine Exhaust 6F. . . . . . . . . . . . . . . . . . . . . . . . .
Engine Lubrication 6G. . . . . . . . . . . . . . . . . . . . . .
Engine Speed Control System 6H. . . . . . . . . . . .
Inducton 6J. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
ENGINE MECHANICAL
CONTENTS
Service Precaution 6A±2. . . . . . . . . . . . . . . . . . . . . .
General Description 6A±3. . . . . . . . . . . . . . . . . . . . .
Engine Diagnosis 6A±4. . . . . . . . . . . . . . . . . . . . . . .
Cylinder Head Cover LH 6A±18. . . . . . . . . . . . . . . . .
Removal 6A±18. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Installation 6A±19. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Cylinder Head Cover RH 6A±21. . . . . . . . . . . . . . . . .
Removal 6A±21. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Installation 6A±22. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Common Chamber 6A±24. . . . . . . . . . . . . . . . . . . . . .
Removal 6A±24. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Installation 6A±24. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Exhaust Manifold LH 6A±26. . . . . . . . . . . . . . . . . . . . .
Removal 6A±26. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Installation 6A±26. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Exhaust Manifold RH 6A±27. . . . . . . . . . . . . . . . . . . .
Removal 6A±27. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Installation 6A±27. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Crankshaft Pulley 6A±28. . . . . . . . . . . . . . . . . . . . . . .
Removal 6A±28. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Installation 6A±28. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Timing Belt 6A±29. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Removal 6A±29. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Installation 6A±30. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Camshaft 6A±33. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Removal 6A±33. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Installation 6A±33. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Cylinder Head 6A±37. . . . . . . . . . . . . . . . . . . . . . . . . .
Removal 6A±37. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Installation 6A±37. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Valve Stem Oil Controller , Valve Spring and
Valve Guide 6A±39. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Removal 6A±39. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Installation 6A±39. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Piston, Piston Ring and Connecting Rod 6A±40. . . Removal 6A±40. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Installation 6A±41. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Crankshaft and Main Bearings 6A±42. . . . . . . . . . . .
Removal 6A±42. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Installation 6A±43. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Rear Oil Seal 6A±47. . . . . . . . . . . . . . . . . . . . . . . . . . .
Removal 6A±47. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Installation 6A±47. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Engine Assembly 6A±48. . . . . . . . . . . . . . . . . . . . . . . .
Removal 6A±48. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Installation 6A±48. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Cylinder Head 6A±52. . . . . . . . . . . . . . . . . . . . . . . . . .
Cylinder Head and Associated Parts 6A±52. . . . .
Disassembly 6A±52. . . . . . . . . . . . . . . . . . . . . . . . . .
Clean 6A±53. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Inspection and Repair 6A±53. . . . . . . . . . . . . . . . . .
Reassembly 6A±53. . . . . . . . . . . . . . . . . . . . . . . . . .
Valve Spring, Oil Controller, Valve,
Valve Guide 6A±56. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Valve Spring, Oil Controller, Valve,
Valve Guide and Associated Parts 6A±56. . . . . . .
Disassembly 6A±56. . . . . . . . . . . . . . . . . . . . . . . . . .
Inspection and Repair 6A±57. . . . . . . . . . . . . . . . . .
Reassembly 6A±60. . . . . . . . . . . . . . . . . . . . . . . . . .
Valve Clearance Adjustments 6A±61. . . . . . . . . . . . .
Camshaft 6A±63. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Camshaft and Associated Parts 6A±63. . . . . . . . .
Disassembly 6A±63. . . . . . . . . . . . . . . . . . . . . . . . . .
Inspection and Repair 6A±64. . . . . . . . . . . . . . . . . .
Reassembly 6A±66. . . . . . . . . . . . . . . . . . . . . . . . . .
Crankshaft 6A±69. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Crankshaft and Associated Parts 6A±69. . . . . . . .
Disassembly 6A±69. . . . . . . . . . . . . . . . . . . . . . . . . .
Inspection and Repair 6A±70. . . . . . . . . . . . . . . . . .
Inspection and Repair 6A±71. . . . . . . . . . . . . . . . . .
Reassembly 6A±73. . . . . . . . . . . . . . . . . . . . . . . . . .

6A±3
ENGINE MECHANICAL
General Description
Engine Cleanliness And Care
An automobile engine is a combination of many
machined, honed, polished and lapped surfaces with
tolerances that are measured in the thousandths of a
millimeter (ten thousandths of an inch). Accordingly,
when any internal engine parts are serviced, care and
cleanliness are important. Throughout this section, it
should be understood that proper cleaning and protection
of machined surfaces and friction areas is part of the
repair procedure. This is considered standard shop
practice even if not specifically stated.

A liberal coating of engine oil should be applied to all
friction areas during assembly to protect and lubricate
the surfaces on initial operation.

Whenever valve train components, pistons, piston
rings, connecting rods, rod bearings, and crankshaft
journal bearings are removed for service, they should
be retained in order.

At the time of installation, they should be installed in
the same locations and with the same mating
surfaces as when removed.

Battery cables should be disconnected before any
major work is performed on the engine. Failure to
disconnect cables may result in damage to wire
harness or other electrical parts.

The six cylinders of this engine are identified by
numbers; Right side cylinders 1, 3 and 5, Left side
cylinders 2, 4 and 6, as counted from crankshaft
pulley side to flywheel side.
General Information on Engine Service
The following information on engine service should be
noted carefully, as it is important in preventing damage
and contributing to reliable engine performance:

When raising or supporting the engine for any reason,
do not use a jack under the oil pan. Due to the small
clearance between the oil pan and the oil pump
strainer, jacking against the oil pan may cause
damage to the oil pick±up unit.

The 12±volt electrical system is capable of damaging
circuits. When performing any work where electrical
terminals could possibly be grounded, the ground
cable of the battery should be disconnected at the
battery.

Any time the intake air duct or air cleaner is removed,
the intake opening should be covered. This will
protect against accidental entrance of foreign
material into the cylinder which could cause extensive
damage when the engine is started.
Cylinder Block
The cylinder block is made of aluminum die±cast casting
for 75
V±type six cylinders. It has a rear plate integrated
structure and employs a deep skint. The cylinder liner is
cast and the liner inner diameter and crankshaft journal
diameter are classified into grades. The crankshaft is
supported by four bearings of which width of No.3 bearing
on the body side is different in order to support the thrust
bearing. The bearing cap is made of nodular cast iron and
each bearing cap uses four bolts and two side bolts.
Cylinder Head
The cylinder head, made of aluminum alloy casting
employs a pent±roof type combustion chamber with a
spark plug in the center. The intake and exhaust valves
are placed in V±type design. The ports are cross±flow
type.
Valve Train
Intake and exhaust camshaft on the both side of banks
are driven through an camshaft drive gear by timing belt.
The valves are operated by the camshaft and the valve
clearance is adjusted to select suitable thickness shim.
Intake Manifold
The intake manifold system is composed of the aluminum
cast common chamber and intake manifold attached with
six fuel injectors.
Exhaust Manifold
The exhaust manifold is made of nodular cast iron.
Pistons and Connecting Rods
Aluminum pistons are used after selecting the grade that
meets the cylinder bore diameter. Each piston has two
compression rings and one oil ring. The piston pin is made
of chromium steel is offset 1mm toward the thrust side,
and the thrust pressure of piston to the cylinder wall varies
gradually as the piston travels. The connecting rods are
made of forged steel. The connecting rod bearings are
graded for correct seze selection.
Crankshaft and Bearings
The crankshaft is made of Ductile cast±iron. Pins and
journals are graded for correct size selection for their
bearing.
Engine Lubrication
The oil discharged by a trochoid±type oil pump driven by
the crankshaft is fed through full±flow oil filter and to the oil
gallery provided under the crankshaft bearing cap. The oil
is then led to the crankshaft journals and cylinder head.
The crank pins are lubricated with oil from crankshaft
journals through oil holes. Also, an oil jet is fed to each
cylinder from crankshaft juornals on the connecting rod
for piston cleaning. The oil pan flange is dealed with liquid
packing only; do not deform or damage the flange surface
during removal or installation.

6A±5
ENGINE MECHANICAL
4. Engine Lacks Compression
Condition
Possible causeCorrection
Engine lacks compressionSpark plug loosely fitted or spark
plug gasket defectiveTighten to specified torque or replace
gasket
Valve timing incorrectAdjust
Cylinder head gasket defectiveReplace gasket
Valve incorrectly seatedLap valve
Valve stem seizedReplace valve and valve guide
Valve spring weakened or brokenReplace
Cylinder or piston rings wornOverhaul engine
Piston ring seizedOverhaul engine.
Engine Compression Test Procedure
1. Start and run the engine until the engine reaches
normal operating temperature.
2. Turn the engine off.
3. Remove all the spark plugs.
4. Remove ignition coil fuse (15A) and disable the
ignition system.
5. Remove the fuel pump relay from the relay and fuse
box.
6. Engage the starter and check that the cranking speed
is approximately 300 rpm.7. Install cylinder compression gauge into spark plug
hole.
8. With the throttle valve opened fully, keep the starter
engaged until the compression gage needle reaches
the maximum level. Note the reading.
9. Repeat the test with each cylinder.
If the compression pressure obtained falls below the
limit, engine overhaul is necessary.
Limit; 1000 kPa (145 psi)

6A±11
ENGINE MECHANICAL
Condition CorrectionPossible cause
Engine overheatingLevel of Engine Coolant too lowReplenish
Fan clutch defectiveReplace
Incorrect fan installedReplace
Thermostat defectiveReplace
Engine Coolant pump defectiveCorrect or replace
Radiator cloggedClean or replace
Radiator filler cap defectiveReplace
Level of oil in engine crankcase too
low or wrong engine oilChange or replenish
Resistance in exhaust system
increasedClean exhaust system or replace
defective parts
Throttle Position Sensor adjustment
incorrectReplace with Throttle Valve ASM
Throttle Position Sensor circuit open
or shortedCorrect or replace
Cylinder head gasket damagedReplace
Engine overcoolingThermostat defectiveReplace (Use a thermostat set to
open at 82
C (180
F))
Engine lacks compressionÐÐÐÐRefer to Hard Start
OthersTire inflation pressure abnormalAdjust to recommended pressures
Brake dragAdjust
Clutch slippingAdjust or replace
Level of oil in engine crankcase too
highCorrect level of engine oil
Exhaust Gas Recirculation Valve
defectiveReplace
Engine Noisy
Abnormal engine noise often consists of various noises
originating in rotating parts, sliding parts and othermoving parts of the engine. It is, therefore, advisable to
locate the source of noise systematically.
Condition
Possible causeCorrection
Noise from crank journals or from
crank bearings
(Faulty crank journals and crankOil clearance increased due to worn
crank journals or crank bearingsReplace crank bearings and
crankshaft or regrind crankshaft and
install the undersize bearing
yj
bearings usually make dull noise that
becomes more evident when
accelerating)Crankshaft out of roundReplace crank bearings and
crankshaft or regrind crankshaft and
install the undersize bearing
Crank bearing seizedCrank bearing seized. Replace crank
bearings and crankshaft or regrind
crankshaft and install the undersize
bearing
Troubleshooting Procedure
Short out each spark plug in sequence using insulated
spark plug wire removers. Locate cylinder with defectivebearing by listening for abnormal noise that stops when
spark plug is shorted out.

6A±14
ENGINE MECHANICAL
Condition CorrectionPossible cause
Trouble in emission control systemHeated Oxygen Sensor circuit openCorrect or replace
Heated Oxygen Sensor defectiveReplace
Signal vacuum hose loosely fitted or
defectiveCorrect or replace
EGR Valve circuit open or shortedCorrect or replace
Exhaust Gas Recirculation Valve
defectiveReplace
ECT Sensor circuit open or shortedCorrect or replace
Canister Purge Valve circuit open or
shortedCorrect or replace
Canister Purge Valve defectiveReplace
ECT Sensor defectiveReplace
Positive Crankcase Ventilation
(PCV) valve and hose cloggedCorrect or replace
Evaporator systemRefer to Section 6E
Trouble in ignition systemÐÐÐÐRefer to ªEngine Lacks Powerº
Trouble in cylinder head partsCarbon deposits in combustion
chamberRemove carbon
Carbon deposit on valve, valve seat
and valve guideRemove carbon
Engine Oil Consumption Excessive
ConditionPossible causeCorrection
Oil leakingOil pan drain plug looseRetighten or replace gasket
Crankcase fixing bolts loosenedRetighten
Oil pan setting bolts loosenedRetighten
Oil pan gasket brokenReplace gasket
Front cover retaining bolts loose or
gasket brokenRetighten or replace gasket
Head cover fixing bolts loose or
gasket brokenRetighten or replace gasket
Oil cooler adapter crackedReplace
Oil cooler center bolt looseRetighten
Oil cooler O±ring brokenReplace
Oil cooler piping loose or brokenRetighten or replace
Oil filter adapter crackedReplace
Oil filter attaching bolt loose or rubber
gasket brokenRetighten or replace oil filter
Oil cooler brokenReplace
Crankshaft front or rear oil seal
defectiveReplace oil seal
Oil pressure unit loose or brokenRetighten or replace
Blow±by gas hose brokenReplace hose
Positive Crankcase Ventilation Valve
cloggedClean
Engine/Transmission coupling failedReplace oil seal

6A±16
ENGINE MECHANICAL
Lubrication Problems
ConditionPossible causeCorrection
Oil pressure too lowWrong oil in useReplace with correct engine oil
Relief valve stickingReplace
Oil pump not operating properlyCorrect or replace
Oil pump strainer cloggedClean or replace strainer
Oil pump wornReplace
Oil pressure gauge defectiveCorrect or replace
Crankshaft bearing or connecting
rod bearing wornReplace
Oil contaminationWrong oil in useReplace with correct engine oil
Oil filter cloggedReplace oil filter
Cylinder head gasket damageReplace gasket
Burned gases leakingReplace piston and piston rings or
cylinder body assembly
Oil not reaching valve systemOil passage in cylinder head or
cylinder body cloggedClean or correct
Engine Oil Pressure Check
1. Check for dirt, gasoline or water in the engine oil.
a. Check the viscosity of the oil.
b. Change the oil if the viscosity is outside the
specified standard.
c. Refer to the ªMaintenance and Lubricationº section
of this manual.
2. Check the engine oil level.
The level should fall somewhere between the ªADDº
and the ªFULLº marks on the oil level dipstick.
If the oil level does not reach the ªADDº mark on the
oil level dipstick, engine oil must be added.3. Remove the oil pressure unit.
4. Install an oil pressure gauge.
5. Start the engine and allow the engine to reach normal
operating temperature (About 80
C).
6. Measure the oil pressure.
Oil pressure should be:
392±550 kPa (56.9±80.4 psi) at 3000 rpm.
7. Stop the engine.
8. Remove the oil pressure gauge.
9. Install the oil pressure unit.
10. Start the engine and check for leaks.

6A±18
ENGINE MECHANICAL
Cylinder Head Cover LH
Removal
1. Disconnect battery ground cable.
2. Drain engine coolant from faucet bottom of radiator.
3. Remove engine cover from the dowels on the
common chamber.
F06RW018
4. Remove air cleaner duct assembly (3) and air cleaner
element (4).
130RW001
Legend
(1) Positive Crankcase Ventilation Hose Connector
(2) Intake Air Temperature Sensor
(3) Air Cleaner Duct Assembly
(4) Air Cleaner Element
(5) Mass Air Flow Sensor
NOTE: Disconnect the mass air flow (MAF) sensor
connector, intake air temperature (IAT) sensor connector,
and positive crankcase ventilation (PCV) hose before
hand the air cleaner duct assembly is removed.5. Disconnect following wiring connectors and bonding
cable:

Manifold Absolute Pressure (MAP) sensor

Vacuum Switching Valve (VSV) for Induction Air
Control Valve (IACV) actuator

Ignition coils for left bank

Fuel injectors for left bank

Idle air control (IAC) valve

Throttle position sensor (TPS)

Bonding cable

Others as necessitated
6. Disconnect following vacuum hoses:

Brake master VAC

Canister

VSV for IACV actuator

Duty solenoid valve

PCV
7. Disconnect radiator upper and lower hoses
8. Remove engine harness from the cylinder head
cover.
9. Remove the upper fan guide.
10. Remove cooling fan and clutch assembly.
11. Remove drive belt by pushing down the auto
tensioner using spanner as illustrated.
F06RW019