oil ISUZU TF SERIES 2004 Workshop Manual

6-12 ENGINE DIAGNOSIS (C24SE)
Engine Oil Consumption Excessive
Condition Possible cause Correction
Oil leaking Oil pan drain plug loose Retighten or replace gasket
Oil pan setting bolds loosened Retighten
Oil pan gasket broken Replace gasket
Front cover retaining bolts loose
or gasket broken Retighten or replace gasket
Head cover retaining bolts loose
or gasket broken Retighten or replace gasket
Oil filter adapter cracked Replace
Oil filter attaching bolt loose or
rubber gasket broken Retighten or replace oil filter
Crankshaft front or rear oil seal
defective Replace oil seal
Oil pressure unit loose or broken Retighten or replace
Blow-by gas hose broken Replace hose
Engine/Transmission coupling
area Replace oil seal
Oil leaking into combustion
chambers due to poor seal in
valve system Valve stem oil seal defective Replace
Valve stem or valve guide worn Replace valve and valve guide
Oil leaking into combustion
chambers due to poor seal in
cylinder parts Cylinders and pistons worn
excessively Rebore cylinder and replace
pistons and others
Piston ring gaps incorrectly
positioned Correct
Piston rings set with wrong side
up Correct
Piston rings sticking Rebore cylinder and replace
pistons and others
Piston ring and ring groove worn Replace pistons and others
Return ports in oil rings clogged Clean piston and replace rings
Crank case ventilation, Positive
Crankcase Ventilation System
malfunctioning Positive Crankcase Ventilation
Hose clogged Clean
Others Improper oil viscosity Use oil of recommended S.A.E.
viscosity
Continuous high speed driving
and or severe usage such as
trailer towing Continuous high speed operation
and or severe usage will normally
cause increased oil consumption

ENGINE DIAGNOSIS (C24SE) 6-13
Fuel Consumption Excessive
Condition Possible cause Correction
Trouble in fuel system Mixture too rich or too lean due to
trouble in fuel injection system Refer to "Abnormal Combustion"
Fuel cut function does not act Refer to "Abnormal Combustion"
Trouble in ignition system Misfiring or abnormal combustion
due to trouble in ignition system Refer to Hard Start or Abnormal
Combustion Troubleshooting
Guide
Others Engine idle speed too high Reset Idle Air Control Valve
Returning of accelerator control
sluggish Correct
Fuel system leakage Correct or replace
Clutch slipping Correct
Brake drag Correct
Selection of transmission gear
incorrect Caution operator of incorrect gear
selection
Oil Problems
Condition Possible cause Correction
Oil pressure too low Wrong oil in use Replace with correct engine oil
Relief valve sticking Replace
Oil pump not operating properly Correct or replace
Oil pump strainer clogged Clean or replace strainer
Oil pump worn Replace
Oil pressure gauge defective Correct or replace
Crankshaft bearing or connecting
rod bearing worn Replace
Oil contamination Wrong oil in use Replace with new engine oil
Oil filter clogged Replace oil filter
Cylinder head gasket damage Replace gasket
Burned gases leaking Replace piston and piston rings or
rebore cylinders
Oil not reaching valve system Oil passage in cylinder head or
cylinder body clogged Clean 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 "Maintenance and Lubrication"
section of this manual.
2. Check the engine oil level.
The level should fall somewhere between the
"ADD" and the "FULL" marks on the oil level
dipstick.
If the oil level does not reach the "ADD" 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:
150 kPa(21.8 psi) at idle speed.
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-2 ENGINE MECHANICAL (C24SE)
PAGE
Camshaft Housing, Check for Plance Surface ......................................................... 6A-39
Cylinder Head, Removal and Installation .................................................................. 6A-39
Cylinder Head, Disassemble and Assemble ............................................................. 6A-42
Valve, Grind ................................................................................................................. 6A-44
Valve Guide, Ream ..................................................................................................... 6A-44
Valve Seating, Mill ....................................................................................................... 6A-45
Cylinder Head, Overhaul............................................................................................. 6A-45
Flywheel ....................................................................................................................... 6A-46
Starter Ring Gear(Manual Transmission) ................................................................. 6A-47
Seal Ring, Crankshaft ................................................................................................. 6A-48
Seal Ring, Crankshaft Rear ........................................................................................ 6A-48
Oil Pan and Bearing Bridge........................................................................................ 6A-49
OPERATIONS ON CRANK DRIVE ................................................................................... 6A-51
Con-Rod Bearing......................................................................................................... 6A-51
Piston with Con-Rod ................................................................................................... 6A-51
Con-Rod ....................................................................................................................... 6A-52
Pistion Rings ............................................................................................................... 6A-53
OPERATIONS ON REMOVED ENGINE ........................................................................... 6A-55
Crankshaft ................................................................................................................... 6A-55
Bearing Free Play Measurement ................................................................................ 6A-57
Plastigage Method ...................................................................................................... 6A-57
Micrometer and gauge method .................................................................................. 6A-58
Bypass Valve ............................................................................................................... 6A-59
Oil Filter ....................................................................................................................... 6A-59
Oil Pump ...................................................................................................................... 6A-59
Oil Pump Safety Valve ................................................................................................ 6A-60
Oil Pump(Overhaul) .................................................................................................... 6A-60
OPERATIONS ON OIL CIRCULATION ............................................................................ 6A-61
Cylinder Head Safety Valve ........................................................................................ 6A-61
OPERATIONS ON COOLING SYSYTEM ......................................................................... 6A-63
Cooling System, Check for Leakes ........................................................................... 6A-63
Cooling System, Fill Up and Bleed ............................................................................ 6A-63
Refill Coolant ............................................................................................................... 6A-64
Ignition Timing, Check................................................................................................ 6A-64

ENGINE MECHANICAL (C24SE) 6A-3
PAGE
ENGINE EXTERNAL PARTS ............................................................................................ 6A-65
Radiator ....................................................................................................................... 6A-65
Thermostat................................................................................................................... 6A-66
Water Pump ................................................................................................................. 6A-66
Coating sealing surfaces with Silicone Grease ....................................................... 6A-67
Alternator ..................................................................................................................... 6A-67
Starter .......................................................................................................................... 6A-67
V-belt Tension of Alternator ....................................................................................... 6A-68
FUEL INJECTION SYSTEM.............................................................................................. 6A-69
Map Sensor.................................................................................................................. 6A-69
Pressure Regulator ..................................................................................................... 6A-69
ECM (Engine Control Module).................................................................................... 6A-69
ECT ............................................................................................................................... 6A-70
Idle Air Control(IAC) Valve.......................................................................................... 6A-70
Ignition Coil ................................................................................................................. 6A-70
Crank Position Sensor................................................................................................ 6A-71
FUEL INJECTOR .............................................................................................................. 6A-72
Knock Sensor .............................................................................................................. 6A-72
Oxygen Sensor ............................................................................................................ 6A-73
Throttle Valve Position Sensor .................................................................................. 6A-73
Acclelerator Pedal and Cable..................................................................................... 6A-73
Air Cleaner Filter ......................................................................................................... 6A-74
Spark Plug Thread ...................................................................................................... 6A-75
TECHNICAL DATA ........................................................................................................... 6A-76
Recommended Troque Values................................................................................... 6A-87
SPECIAL SERVICE TOOL................................................................................................ 6A-88

6A-4 ENGINE MECHANICAL (C24SE)
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 surfaced 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 four cylinders of this engine are identified by numbers; cylinders 1, 2, 3 and 4, as counted from crankshaft
pulley.
General Information on Engine Service
The following information on engine service should be noted carefully, as it is important in preventing damage and

ENGINE MECHANICAL (C24SE) 6A-5
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 possible 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 cast iron. The crankshaft is supported by five bearings. The bearing cap is made of
nodular cast iron.

Cylinder Head
The cylinder head is made of aluminum alloy casting with a spark plug in the center.

Valve Train
Valve system is a single over head camshaft.
The valves clearance adjustment are hydraulic.
Hydraulic valve lifter adjustment, no adjustment necessary.

Intake Manifold
The intake manifold is made of aluminum alloy.

Exhaust Manifold
The exhaust manifold is made of high Si-Mo nodular 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 cast hardened steel. The connecting rod bearings are
made of modular cast iron. The connecting rod bearings are made of steel backed with tri-metal babbitt metal.

Crankshaft and Bearings
The crank shaft is made of modular cast iron. Pins and journal are graded for correct size selection for their bearing.

6A-6 ENGINE MECHANICAL (C24SE)
ENGINE PICTORIAL
Front View
“4WD OIL PAN”

ENGINE MECHANICAL (C24SE) 6A-7
Inlet Side View
“4WD OIL PAN”

6A-8 ENGINE MECHANICAL (C24SE)
Rear View
“4WD OIL PAN”

ENGINE MECHANICAL (C24SE) 6A-9
Exhaust Side View
“4WD OIL PAN”