2007 ISUZU KB P190 low oil pressure

6G-2 ENGINE LUBRICATION
General Description
Legend
1 Oil Strainer
2 Oil Pump
3 Relief Valve
4 Oil Filter
5 Safety Valve
6 Oil Gallery
7 Crankshaft Bearing
8 Crankshaft 9 Connecting Rod Bearing
10 Connecting Rod
11 Piston
12 Oil Gallery; Cylinder Head
13 Camshaft
14 Camshaft Journal
15 HLV
16 Check relief valve
17 Oil Pan




A gear-type oil pump is directly driven by the crankshaft and
draws oil from the oil pan, via the suction pipe. If then passes
the pressured oil through a full-flow disposable oil filter, to the
main oil gallery in the cylinder Block. An oil pump pressure
relief valve and oil filter bypass valve are incorporated in the
system.
From the main oil gallery in the cylinder block, the cylinder
head and crankshaft main bearings are supplied with oil.
The camshaft bearings and hydraulic tappets are supplied
through the main feed galleries in the cylinder head. Vent
valves allow air to be expelled from the oil galleries in the
cylinder head. The balance shaft journals are directly fed from
the crankshaft main bearings. The connecting rod bearings are
fed via passages in the crankshaft. The oil returns to the oil
pan via passages in the cylinder block.



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ISUZU KB P190 2007

ENGINE LUBRICATION 6G-5

Inspection and Repair
CAUTION: Make necessary correction or parts
replacement if wear, damage or any other abnormal
conditions are found through inspection.
Body and Gears
The pump assembly must be replaced if one or more of the
conditions below is discovered during inspection:
Indentation of gear pair - Use feeler strip and straight edge.
Dimension: 0.03 mm to 0.10 mm
(0.0012 to 0.0039 in)


Oil Strainer
Check the oil strainer for cracking and scoring. If cracking and
scoring are found, the oil strainer must be replaced.




Reassembly
1. Install oil pressure switch to the oil pump.
Torque: 40 N ⋅
⋅⋅
⋅
m (4.1 kgf ⋅
⋅⋅
⋅
m)
2. Install the oil pump with the sleeve and the gasket.
Torque: 6 N ⋅
⋅⋅
⋅
m (0.6 kgf ⋅
⋅⋅
⋅
m)
3. Install oil strainer.
Torque: 8 N ⋅
⋅⋅
⋅
m (0.8 kgf ⋅
⋅⋅
⋅
m)
4. Install the oil pan.
Tighten the bolts:
15 N ⋅
⋅⋅
⋅
m (1.5 kgf ⋅
⋅⋅
⋅
m)
5. Install crankshaft timing pulley.
Tighten the bolts:
20 N ⋅
⋅⋅
⋅
m (2.0 kgf ⋅
⋅⋅
⋅
m)


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ISUZU KB P190 2007

Engine Mechanical – V6 Page 6A1–2

Visual / Physical Inspection ................................................................................................................................ 28
Intermittent ........................................................................................................................................................... 28
2.3 Engine Misfire without Internal Engine Noises .................................................................................. ............... 29
2.4 Engine Misfire with Abnormal Internal Lower Engine Noises...................................................................... .... 30
2.5 Engine Misfire with Abnormal Valve Train Noise .............................................................................................. 31
2.6 Engine Misfire with Coolant Consumption ........................................................................................................ 31
2.7 Engine Misfire with Excessive Oil Consumption .................................................................................. ............ 31
2.8 Engine Noise on Start-up, but only Lasting a Few Seconds ....................................................................... ..... 31
2.9 Upper Engine Noise, Regardless of Engine Speed........................................................................................... 33
2.10 Lower Engine Noise, Regardless of Engine Speed ................................................................................. ......... 34
2.11 Engine Noise Under Load ................................................................................................................................... 35
2.12 Engine Will Not Crank – Crankshaft Will Not Rotate ............................................................................. ........... 35
2.13 Coolant in Combustion Chamber ....................................................................................................................... 37
Definition .............................................................................................................................................................. 37
2.14 Coolant in Engine Oil.......................................................................................................... ................................. 37
Definition .............................................................................................................................................................. 37
2.15 Engine Compression Test ........................................................................................................ ........................... 38
Preliminary Steps................................................................................................................................................. 38
Engine Cylinder Compression Test ............................................................................................... .................... 38
Test Result Evaluation......................................................................................................................................... 38
2.16 Cylinder Leakage Test .......................................................................................................... ............................... 39
2.17 Engine Oil Consumption Diagnosis ............................................................................................... .................... 39
Definition .............................................................................................................................................................. 39
2.18 Engine Oil Leak Diagnosis ...................................................................................................... ............................ 40
Introduction .......................................................................................................................................................... 40
Locating and Identifying the Leak .............................................................................................. ........................ 40
Visual Inspection ................................................................................................................................................. 40
Powder Method .................................................................................................................. .................................. 40
Black Light and Dye Method ..................................................................................................... .......................... 40
Possible Causes for Engine Oil Leaks ........................................................................................... .................... 41
2.19 Engine Oil Pressure Diagnosis ........................................................................................................................... 42
2.20 Accessory Drive Belt Diagnosis ................................................................................................. ........................ 42
Tension Check ..................................................................................................................................................... 42
Inspect .................................................................................................................................................................. 42
Drive Belt Chirp .................................................................................................................................................... 43
Definition .......................................................................................................................................................... 43
Diagnostic Aids................................................................................................................................................. 43
Test Description ............................................................................................................... ................................ 43
Diagnostic Table............................................................................................................................................... 44
Drive Belt Squeal .............................................................................................................. ................................... 45
Definition .......................................................................................................................................................... 45
Diagnostic Aids................................................................................................................................................. 45
Test Description ............................................................................................................... ................................ 45
Diagnostic Table............................................................................................................................................... 46
Drive Belt Whine ............................................................................................................... ................................... 46
Definition .......................................................................................................................................................... 46
Diagnostic Aids................................................................................................................................................. 46
Test Description ............................................................................................................... ................................ 46
Diagnostic Table............................................................................................................................................... 47
Drive Belt Rumble .............................................................................................................. .................................. 47
Definition .......................................................................................................................................................... 47
Diagnostic Aids................................................................................................................................................. 48
Test Description ............................................................................................................... ................................ 48
Diagnostic Table............................................................................................................................................... 48
Drive Belt Vibration........................................................................................................... ................................... 49
Definition .......................................................................................................................................................... 49
Diagnostic Aids................................................................................................................................................. 49
Test Description ............................................................................................................... ................................ 49
Diagnostic Table............................................................................................................................................... 50
Drive Belt Falls Off ........................................................................................................... .................................... 50

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ISUZU KB P190 2007

Engine Mechanical – V6 Page 6A1–16

Oil Pump

Figure 6A1 – 8
Legend
1 Lower Primary Timing Chain Guide
2 Lower Primary Timing Chain Guide Bolt
3 Oil Pump Housing
4 Oil Pump Cover
5 Oil Pump Gerotor Outer Ring
6 Oil Pump Gerotor Inner Ring 7 Oil Pump Cover Bolt
8 Oil Pressure Relief Valve Bore Plug
9 Oil Pressure Relief Valve Spring
10 Oil Pressure Relief Valve
11 Oil Pressure Relief Valve Bore Plug Retainer Clip
12 Oil Pump Bolt
NOTE
Oil pump components are not serviced
individually.

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ISUZU KB P190 2007

Engine Mechanical – V6 Page 6A1–22

Crankshaft
The crankshaft is a forged steel design with four main bearings. The number three main bearing controls crankshaft
thrust. A crankshaft position reluctor wheel is pressed onto the rear of the crankshaft, in front of the rear main journal.
The crankshaft is internally balanced with an integral oil pump drive machined into the nose in front of the front main
journal.
Pistons, Pins and Connecting Rods
The piston assembly (1) is fitted with two low tension
compression rings and one multi-piece oil control ring. The
top compression ring is plasma sprayed, while the second
compression ring is cast iron Napier.
The oil control ring incorporates a steel expander and two
chrome plated steel rails.
The connecting rods are sinter forged steel and have full
floating piston pins. The piston pins are a slip-fit type, into
the bronze bushed connecting rods. Round wire retainers
are used to retain the piston pin into the piston.
The cast aluminium pistons incorporate a polymer coated
skirt to reduce friction.
Figure 6A1 – 17
Camshaft Drive System
Three timing chains are fitted:
• primary (1),
• right-hand secondary (2), and
• left-hand secondary (3), refer to Figure 6A1 – 18 for the HFV6 engine.
The primary timing chain connects the crankshaft sprocket (4) with the left-hand and right-hand intermediate drive shaft
sprockets (5).
Each oil pressure fed intermediate sprocket drives the secondary timing chains, which subsequently drive the respective
cylinder head camshaft position actuators (6).
Two stationary timing chain guides (7) and movable timing chain shoes (8) control secondary timing chain backlash.
Each secondary timing chain shoe is under tension from an oil pressure hydraulically operated tensioner (9). To control
backlash on the primary chain, two stationary timing chain guides (10) and an oil pressure hydraulically actuated
tensioner with built in shoe (11) are fitted.
The tensioners minimise timing chain noise and provide accurate valve action by keeping slack out of the timing chains,
while continuously adjusting for timing chain wear. The tensioners incorporate a plunger that adjusts outward with wear,
minimising backlash. The tensioners are equipped with oiling jets to spray oil onto the timing components during engine
operation. Each tensioner is sealed to the head or block using a rubber coated steel gasket. The gasket traps an
adequate oil reserve to ensure quiet start-up.

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ISUZU KB P190 2007

Engine Mechanical – V6 Page 6A1–24

1.5 Engine Lubrication System
Lubrication Description
A structural diecast aluminium oil pan is fitted that incorporates an oil suction pipe, an oil deflector and an oil level sensor.
The oil suction pipe is bolted into the oil pan and seals to the bottom of the cylinder block with a gasket. The oil deflector
is bolted to the upper portion of the oil pan and ensures oil supply is maintained under all conditions. The oil level sensor
is mounted through the bottom of the oil pan.
A crankshaft driven gerotor oil pump is mounted to the front of the cylinder block. The pump, which incorporates an
internal pressure-relief valve, draws oil from the oil suction tube through the lower passage in the cylinder block. Oil is
then directed through an upper passage to the left-hand side of the cylinder block where the oil filter adapter is mounted.
The oil filter adapter incorporates a top-access, cartridge style oil filter. The filter is accessed through a screw-on cap tha t
incorporates an oil bypass valve. The oil filter adapter housing incorporates a drain back control valve and a threaded oil
pressure sender. Oil flows through a lower passage within the oil filter adapter and through the oil filter cartridge. Filtered
oil travels back through the upper passage of the adapter and into the engine block.
Oil is then directed up and across the front of the cylinder block, through several drilled passages. These front passages
feed oil to each cylinder head, the passage for the main bearings and piston oil jets, the right-hand and left-hand
secondary idler sprockets and to the primary timing chain tensioner.
Each cylinder head passage directs oil into oiling circuits for the stationary hydraulic lash adjusters (SHLAs) and the
camshaft bearing journals. An additional passage in the cylinder head also directs oil to the secondary timing chain
tensioner.
The oil passage that supplies oil to the main bearings also supplies oil to pressure actuated piston cooling oil jets. Each
oil jet is mounted between opposing cylinder bores and directs oil to the two bores to provide extra cooling and control
piston temperatures.
From the front passages, oil is directed to the front of the block where the right-hand and left-hand intermediate drive
shaft sprockets and the primary timing chain tensioner are mounted. Each camshaft timing chain tensioner relies on a
gasket to maintain an oil reserve after the engine is turned off. All camshaft timing chain tensioners incorporate a small
oil jet to supply an oil spray onto the camshaft timing chain components.
Oil returns to the oil pan, either through the camshaft timing chain area or through the drain back passages on the
outboard walls of the cylinder heads and cylinder block.
1.6 Service Notes
Cleanliness and Care
Throughout this Section, correct cleaning and protection of machined surfaces and friction areas is a part of the repair
procedure. This is considered standard workshop practice, even if not specifically stated.
W hen any internal engine part is serviced, care and cleanliness is extremely important.
W hen components are removed for service, they should be marked, organised or retained in a specific order for
reassembly.
At the time of installation, components should be installed in the same location and with the same mating surface as
when removed.
Any engine is a combination of many machined, honed, polished and lapped surfaces with tolerances that are measured
in thousandths of a millimetre. These surfaces should be covered or protected to avoid component damage.
A liberal coating of clean engine oil should be applied to friction areas during assembly, as the lubrication will protect and
lubricate friction surfaces during the initial engine start-up.
Replacing Engine Gaskets
Re-Using Gaskets and Applying Sealants
• do not reuse any gasket unless specified,
• gaskets that can be reused will be identified in the service procedure, and
• do not apply sealant to any gasket or sealing surface unless specified in the service information.
Separating Components
• Use a rubber mallet to separate components.
• Bump the part sideways to loosen the components.
• Bumping should be done at bends or reinforced areas to prevent distortion of parts.
Cleaning Gasket Surfaces
• W here required, remove all gasket and sealing material from the part using a plastic or wood scraper.
• Care must be used to avoid gouging or scraping the sealing surfaces.

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ISUZU KB P190 2007

Engine Mechanical – V6 Page 6A1–29

2.3 Engine Misfire without Internal Engine
Noises
Cause Correction
Abnormalities, severe cracking, bumps or missing areas in
the accessory drive belt.
Abnormalities in the accessory drive system and/or
components may cause engine speed variations that result
in a misfire diagnostic trouble code (DTC). A misfire code
may be present without an actual misfire condition. Replace the accessory drive belt, refer to 3.5
Accessory
Drive Belt.
Refer to 6C1-2 Engine Management – V6 – Diagnostics to
check for DTCs.
W orn, damaged or misaligned accessory drive components
and excessive pulley run-out may lead to a misfire DTC.
A misfire code may be present without an actual misfire
condition. Inspect the components and repair or replace as required.
Refer to 6C1-2 Engine Management – V6 – Diagnostics to
check for DTCs.
Loose or incorrectly fitted flexplate or crankshaft balancer
assembly.
A misfire DTC may be present without an actual misfire
condition. Repair or replace the flexplate or crankshaft balancer as
required, refer to 3.13 Crankshaft Balancer Assembly
or 4.3 Flexplate Assembly.
Refer to 6C1-2 Engine Management – V6 – Diagnostics to
check for DTCs
Restricted exhaust system.
A severe restriction in the exhaust flow can cause
significant loss of engine performance and may set a DTC.
Possible causes of restrictions in the exhaust system
include collapsed/dented pipes and blocked mufflers and/or
catalytic converters. Repair or replace exhaust system components as required,
refer to 8B Exhaust System.
Refer to 6C1-2 Engine Management – V6 – Diagnostics to
check for DTCs
Incorrectly installed or damaged vacuum hoses. Repair or replace vacuum hoses as required.
Incorrect sealing between the intake manifold and cylinder
heads, upper intake manifold and lower intake manifold,
throttle body and intake manifold. Repair or replace the intake manifold, throttle body gaskets,
cylinder heads, throttle body as required.
Incorrectly installed or damaged barometric
pressure(BARO) sensor and/or seal. The seal should not
be torn or damaged. Repair or replace the BARO sensor and/or seal as
required, refer to 6C1-3 Engine Management – V6 –
Service Operations.
Incorrectly installed or damaged EVAP purge solenoid
and/or O-ring seal. Repair or replace the EVAP purge solenoid and/or seal as
required, refer to 6C1-3 Engine Management – V6 –
Service Operations
W orn or loose stationary hydraulic lash adjusters (SHLA)
and/or rocker arms.
The SHLAs, rocker arms and roller bearings should be
intact and in the correct position. Replace the SHLAs and/or rocker arms as required, refer to
3.21 Stationary Hydraulic Lash Adjuster or 3.20
Rocker Arm.
Stuck valves.
Carbon build up on the valve stems can result in the valves
not closing correctly. Repair or replace as required, refer to 3.22 Cylinder Head
Assembly.
Excessively worn or misaligned timing chain/s. Replace the timing chain/s and components as required,
refer to 3.16 Timing Chains, Tensioners, Shoes and
Guides.
W orn camshaft lobes. Replace the camshaft/s and SHLAs as required, refer to
3.19 Camshaft or 3.21 Stationary Hydraulic Lash
Adjuster.
Excessive oil pressure.
A lubrication system with excessive oil pressure may lead
to excessive lash adjuster pump-up and loss of
compression. 1 Perform an oil pressure test, refer to 3.1
Engine Oil.
2 Repair or replace the engine oil pump as required, refer to 3.17 Oil Pump Assembly.

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ISUZU KB P190 2007

Engine Mechanical – V6 Page 6A1–33

2.9 Upper Engine Noise, Regardless of
Engine Speed
NOTE
A cold piston knock, which disappears in
approximately 1.5 minutes from start up, should
be considered acceptable. A cold engine knock
usually disappears when the specific cylinder’s
secondary ignition circuit is grounded out during
diagnosis.
A light rattle/tapping noise may indicate a valve train/upper engine concern, while a low rumble/knocking may indicate a
crankshaft, piston or lower engine concern.
Cause Correction
Low oil pressure. 1 Perform an oil pressure test, refer to 2.19
Engine Oil Pressure Diagnosis.
2 Repair or replace the engine oil pump as required, refer to 3.17 Oil Pump Assembly.
W orn or loose stationary hydraulic lash adjusters (SHLA)
and/or valve rocker arms.
The SHLAs, rocker arm and roller bearings should be intact
and in the correct position. 1 Clean, inspect and replace the camshaft lash
adjusters as required, refer to 3.21 Stationary
Hydraulic Lash Adjuster.
2 Replace the SHLAs and/or rocker arms as required, refer to 3.21 Stationary Hydraulic Lash Adjuster or
3.20 Rocker Arm.
Incorrect lubrication to the stationary hydraulic lash
adjusters and valve rocker arm. Inspect the following components and repair or replace as
required:
• valve rocker arms, refer to 3.20 Rocker Arm.
• stationary hydraulic lash adjusters, refer to 3.21
Stationary Hydraulic Lash Adjuster.
• oil filter by-pass valve, refer to 3.3 Oil Filter
Adaptor.
• oil pump and suction pipe, refer to 3.17 Oil Pump
Assembly.
• cylinder head oil galleries, refer to 3.22 Cylinder Head
Assembly.
• cylinder block oil galleries, refer to 4.7 Cylinder
Block.
Broken Valve Spring. Replace the valve spring, refer to 3.22 Cylinder Head
Assembly.
Stretched or broken timing chain/s and/or damaged timing
chain sprocket teeth. Replace the timing chains or sprockets as required, refer to
3.16 Timing Chains, Tensioners, Shoes and Guides.
W orn or faulty timing chain tensioner or guide. Replace the timing chains or sprockets as required, refer to
3.16 Timing Chains, Tensioners, Shoes and Guides.
W orn camshaft lobes. Replace the camshaft/s and SHLAs as required, refer to
3.19 Camshaft or 3.21 Stationary Hydraulic Lash
Adjuster.
W orn valve guides and/or valve stems. Inspect and repair or replace valves and valve guides as
required, refer to 3.22 Cylinder Head Assembly.
Stuck valves.
Carbon on the valve stem or valve seat may cause the
valve to stay open. Inspect and repair or replace valves and valve guides as
required, refer to 3.22 Cylinder Head Assembly.

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ISUZU KB P190 2007