2007 ISUZU KB P190 ECO mode

Engine Mechanical – V6 Page 6A1–48
Page 6A1–48
2.18 Engine Oil Leak Diagnosis
Introduction
It is important to correctly identify the source of an engine oil leak. For example, a power steering fluid leak or spillage
during servicing can travel across the va lley area of the engine and run-out the weep hole, which is located at the back of
the cylinder block. Failure to correctly identify the source of an engine oil leak can lead to unnecessary replacement of
engine components.
Most fluid leaks can be repaired by repairi ng or replacing the faulty component or resealing the gasket surface. However,
once a leak is identified it is im portant to determine and repair the c ause as well as the leak itself.
Locating and Identifying the Leak
Inspect the leaking fluid and determine whet her it is engine oil, transmission fluid, power steering fluid, brake fluid or
some other fluid. If unsure of the source of the leaking lubricant, a quick check of fluid levels should indicate where the
fluid is coming from, as one or more fluid level should be low.
Visual Inspection
Once the type of leaking fluid has been determined, a visual inspection of the affected system should be performed.
When performing the visual inspection:
1 Bring the vehicle to the normal operating temperature.
2 Park the vehicle over a large s heet of paper or other clean surface.
3 Leave the vehicle idling for 2-3 minut es, then check for dripping fluid.
4 If required, identify the type of fluid leak ing and the approximate location of the leak.
5 Visually inspect the suspected area. A small mirror may assist viewing areas that are difficult to see normally.
6 Check for leaks at all sealing surfaces and fittings.
7 Check for any cracked or damaged components.
8 If the leak cannot be located, completely clean the entire engine and surrounding components, drive the vehicle at
normal operating temperature for several k ilometres and then repeat Steps 3 to 8.
9 If the leak still cannot be located, proceed with either the Powder Method or Black Light and Dye Method as
outlined below.
Powder Method
1 Completely clean the entir e engine and surrounding components.
2 Apply an aerosol type powder (e.g. f oot powder) to the suspected area.
3 Operate the vehicle at normal operating temperature and at varying speeds for several kilometres.
4 Identify the source of the leak from the discoloration of the powder around the suspect components.
5 If required, use a small mirror to assist in vi ewing areas that are difficult to see normally.
6 Refer to Possible Causes for Engine Oil Leaks in this Section, and repair or replace components as required.
Black Light and Dye Method
A black light and die kit Tool No. J28428-E or a commercially av ailable equivalent is available to technicians to aid in
engine oil leak diagnosis. When using a black light and die kit fo r the first time, it is recommended the technician read the
manufacturers instructions prior to using the kit.
1 Add the specified amount of dye, as per manufacturers instructions, into the engine or suspected source of the oil
leak.
2 Operate the vehicle at normal operating temperature and at varying speeds for several kilometres.
3 With the vehicle parked on a flat leve l surface, aim the black light at the suspected component/s. The dyed fluid will
appear as a yellow path leading to the oil leak source
4 Refer to Possible Causes for Engine Oil Leaks in this Section, and repair or replace components as required.

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ISUZU KB P190 2007

Engine Mechanical – V6 Page 6A1–49
Page 6A1–49
Possible Causes for Engine Oil Leaks
Common possible causes for engine oil leaks are:
• higher than recommended fluid levels,
• higher than recommended fluid pressures,
• blocked or faulty fluid filters or pressure relief valve,
• blocked or faulty engine ventilation system,
• incorrectly tightened or damaged fasteners,
• cracked or porous components,
• incorrect gaskets or sealants used,
• incorrect gaskets or sealant installation,
• damaged or worn gaskets or seals, and
• damaged or worn sealing surfaces.

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ISUZU KB P190 2007

Engine Mechanical – V6 Page 6A1–54
Page 6A1–54
Diagnostic Table
Step Action Yes No
1
Did you review the information provided in 2.2 Symptoms, and
perform the required inspections. Go to Step 2 Go to
2.2 Symptoms
2 Confirm the customer compla int. Is there a chirping noise?
Go to Step 3 Refer to Diagnostic
Aids in this Section
3 1 Remove the drive belt, refer to 3.5 Accessory Drive Belt.
2 Operate the engine for no more than 40 seconds.
Does the chirping noise still exist? Accessory drive
system OK.
Go to 2.2
Symptoms, and
restart the diagnosis
of the noise Go to Step 4
4
Inspect for severe pilling, i.e. in excess of 33% of the belt groove
depth.
Do the belt grooves have pilling? Go to Step 5 Go to Step 6
5 Clean the drive belt pulleys with a wire brush.
Are the belt pulleys clean? Go to Step 15 Go to Step 6
6 Inspect for misalignment of the pulleys.
Are the pulleys misaligned? Go to Step 7 Go to Step 8
7 Replace or repair misaligned pulleys.
Did you complete the repair? Go to Step 15 —
8
Inspect for any bent or damaged accessory drive component
mounting brackets.
Did you find any bent or damaged brackets? Go to Step 9 Go to Step 10
9 Replace or repair any bent or damaged Brackets. Did you complete the repairs? Go to Step 15 —
10 Inspect for missing, loose or incorrect fasteners.
Did you find any missing, loose or incorrect fasteners? Go to Step 11 Go to Step 12
11
Tighten any loose fasteners to the to rque specification as provided in
provided in 6. Torque Wrench Specifications.
Replace any incorrect or missing fasteners.
Did you complete the repairs? Go to Step 15 —
12 Inspect for a bent pulley.
Did you find any bent pulleys? Go to Step 13 Go to Step 14
13 Replace bent pulleys as required.
Did you complete the repair? Go to Step 15 —
14 Replace the accessory drive belt, re
fer to 3.5 Accessory Drive Belt.
Did you complete the repair? Go to Step 15 —
15
Reinstall the accessory drive belt and operate the system to confirm
the repair.
Did you correct the chirp noise? Accessory drive
system OK Go to 2.2
Symptoms, and
restart the diagnosis

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ISUZU KB P190 2007

Engine Mechanical – V6 Page 6A1–56
Page 6A1–56
Step Action Yes No
3 1 Remove the drive belt, refer to 3.5 Accessory Drive Belt.
2 Operate the engine for no more than 40 seconds.
Does the squealing noise still exist? Accessory drive
system OK.
Go to 2.2
Symptoms, and
restart the diagnosis
of the noise Go to Step 4
4
Inspect the accessory drive components for a seized bearing and
general malfunctions.
Did you find and correct any seized bearings or general malfunctions
in the accessory drive system? Go to Step 9 Go to Step 5
5
Test the accessory drive belt tensi oner for correct operation, refer to
Accessory Drive Belt Tensioner Diagnosis.
Did you find and repair any problems with t he tensioner? Go to Step 9 Go to Step 6
6
Inspect the accessory drive belt is the correct length, refer to 3.5
Accessory Drive Belt.
Did you find and repair any problems with the drive belt length? Go to Step 9 Go to Step 7
7 Inspect the accessory drive pulleys for misalignment.
Did you find and correct any misaligned accessory drive pulleys? Go to Step 9 Go to Step 8
8 Check the accessory drive pulleys are the correct size.
Did you find and replace any incorrect pulleys? Go to Step 9 Refer to Diagnostic
Aids in this Section
9 Reinstall the accessory drive belt and operate the system to confirm
the repair.
Did you correct the squeal noise? Accessory drive
system OK Go to 2.2
Symptoms, and
restart the diagnosis

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ISUZU KB P190 2007

Engine Mechanical – V6 Page 6A1–57
Page 6A1–57
Drive Belt Whine
Definition
Accessory drive belt whine can be defined as a high-pitched continuous noise that is most likely to be caused by a failed
bearing in one of the acce ssory drive components.
Diagnostic Aids
The drive belts themselves will not caus e a whine. If the noise is intermittent, confirm the accessory drive components by
varying their loads, making sure they are operated to their maximum capacity. An overcharged A/C system, restrictions
in the power steering pressure circuit or a faulty generator or coolant pump ar e likely causes of accessory drive belt
whine.
Test Description
The numbers below refer to steps in the diagnostic table.
3 The noise may be an internal engine noise. Removing the drive belt and operating the engine briefly will confirm
whether or not the noise is related to the drive belt.
CAUTION
When running the engine with the accessory
drive belt removed, the coolant pump will not
be operating and the engine may overheat if
left unsupervised even for a short period.
NOTE
There may also be a number of DTCs set when
running the engine with the accessory drive belt
removed.
4 The inspection of bearings should include the following accessory drive components:
• drive belt tensioners,
• drive belt idlers,
• generator,
• power steering pump,
• coolant pump, and
• A/C compressor.
The drive belt may need to be installed and the accessory drive components operated separ ately, at varying loads
to confirm the location of the faulty bearing, refer to the relevant Sections for component inspection and repair
procedures.
Diagnostic Table
Step Action Yes No
1
Did you review the information provided in 2.2 Symptoms, and
perform the required inspections. Go to Step 2 Go to
2.2 Symptoms
2 Confirm the customer compla int. Is there a whining noise?
Go to Step 3 Refer to Diagnostic
Aids in this Section
3 1 Remove the drive belt, refer to 3.5 Accessory Drive Belt.
2 Operate the engine for no more than 40 seconds.
Does the whining noise still exist? Accessory drive
system OK
Go to 2.2
Symptoms, and
restart the diagnosis Go to Step 4
4 Inspect the accessory drive components for a faulty or seized
bearings and general malfunctions.
Did you find and correct any faulty/seized bearings or general
malfunctions in the accessory drive system? Go to Step 5 Refer to Diagnostic
Aids in this Section
5 Reinstall the accessory drive belt and operate the system to confirm
the repair.
Did you correct the whine? Accessory drive
system OK Go to 2.2
Symptoms, and
restart the diagnosis

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ISUZU KB P190 2007

Engine Mechanical – V6 Page 6A1–58
Page 6A1–58
Drive Belt Rumble
Definition
Accessory drive belt rumble can be defined as a low pitch tapping, knocking or thumping noise heard at or just above
idle, once per rotation of the drive belt or a specific co mponent. Drive belt rumble is generally caused by one of the
following:
• pilling or strings in the drive belt grooves,
• separation of the drive belt, or
• a damaged or faulty drive belt.
NOTE
Pilling is the small balls (p ills) or strings of rubber
in the belt grooves caused by the accumulation of
rubber dust.
Diagnostic Aids
Vibration from the engine may cause a body component or other parts to emit a rumbling noise.
The drive belt may have a condition that cannot be seen or felt. Sometimes the replacement of the belt may be the only
way to confirm the belt is faulty.
If the drive belt has been replaced and the di agnostic table completed, but the rumble is still present only when the drive
belt is installed, an accessory drive component such as t he A/C compressor may be the cause. Varying the load to each
accessory drive component in turn, should help isolate which component is causing the noise.
Test Description
The numbers below refer to steps in the diagnostic table.
2 Confirms the symptom exists at the time of di agnosis. Other vehicle components may be causing the noise.
3 Confirms the accessory drive belt is the cause of the noise. Drive belt rumbling is often confused with an internal
engine noise due to the similarity in the description. Removing the drive belt and operating the engine briefly will
confirm whether or not the noise is related to the drive belt.
CAUTION
When running the engine with the accessory
drive belt removed, the coolant pump will not
be operating and the engine may overheat if
left unsupervised even for a short period.
NOTE
There may also be a number of DTCs set when
running the engine with the accessory drive belt
removed.
4 Inspecting the drive belt is to ensure t hat it is not causing the noise. Small cracks across the ribs of the drive belt
will not cause the noise and are not just ification alone to replace the belt. Belt separation can be identified by the
ply of the belt separating and may be seen at the edge of the belt or felt as lumps under the belt.
5 Small amounts of pilling is a normal condition and is deemed acceptable. When the pilling is severe (33% of the
belt groove depth), the belt does not have a smoot h surface to run on and should be replaced.
Diagnostic Table
Step Action Yes No
1
Did you review the information provided in 2.2 Symptoms, and
perform the required inspections. Go to Step 2 Go to
2.2 Symptoms
2 Confirm the customer compla int. Is there a rumbling noise?
Go to Step 3 Refer to Diagnostic
Aids in this Section
3 1 Remove the drive belt, refer to 3.5 Accessory Drive Belt.
2 Operate the engine for no more than 40 seconds.
Does the rumbling noise still exist? Accessory drive
system OK
Go to 2.2
Symptoms, and
restart the diagnosis Go to Step 4

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ISUZU KB P190 2007

Engine Mechanical – V6 Page 6A1–60
Page 6A1–60
Drive Belt Vibration
Definition
Accessory drive belt vibration can be defined as a drive belt that jumps, shakes or rattles. Accessory drive belt vibration
is usually indicated by one of the following:
• the vibration is engine speed related, or
• the vibration is sensitive to accessory drive system load.
Diagnostic Aids
The accessory drive components such as the A/C compre ssor or generator can have an affect on engine vibration.
To aid in locating which component is causing the vibration, vary the load to each accessory drive component in turn and
note the effect it has on the vibration if any.
Test Description
The numbers below refer to steps in the diagnostic table.
2 Confirms the symptom exists at the time of di agnosis. Other vehicle components may be causing the noise.
3 Confirms the accessory drive belt is the cause of the noise. Drive belt rumbling is often confused with an internal
engine noise due to the similarity in the description. Removing the drive belt and operating the engine briefly will
confirm whether or not the noise is related to the drive belt.
CAUTION
When running the engine with the accessory
drive belt removed, the coolant pump will not
be operating and the engine may overheat if
left unsupervised even for a short period.
NOTE
There may also be a number of DTCs set when
running the engine with the accessory drive belt
removed.
4 The drive belt may cause a vibration. Inspecting the drive belt is considerably easier while the drive belt is
removed.
6 Inspecting the fasteners can eliminate the possibility that an inco rrect fastener has been installed.
8 This step should only be performed if t he coolant pump is driven by the drive belt. Inspect the coolant pump for a
bent shaft. Also inspect the coolant pump bearings for smooth operation and excessive play. Compare the coolant
pump with a known good pump.
9 Accessory drive component brackets that are bent, cra cked or loose may put extra strain on the accessory
component causing it to vibrate.
Diagnostic Table
Step Action Yes No
1
Did you review the information provided in 2.2 Symptoms, and
perform the required inspections. Go to Step 2 Go to
2.2 Symptoms
2 Confirm the customer compla int. Is there a rumbling noise?
Go to Step 3 Refer to Diagnostic
Aids in this Section
3 1 Remove the drive belt, refer to 3.5 Accessory Drive Belt.
2 Operate the engine for no more than 40 seconds.
Does the vibration noise still exist? Accessory drive
system OK.
Go to 4.2
Symptoms, and
restart the diagnosis Go to Step 4
4 Inspect the accessory drive belt for damage, wear, debris build-up or
sections of missing ribs.
Did you find any damage, wear, debris build-up or missing ribs? Go to Step 5 Go to Step 6
5 Install a new accessory drive belt, refer to 3.5 Accessory Drive Belt.
Did you replace the accessory drive belt? Go to Step 10 —

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ISUZU KB P190 2007

Engine Mechanical – V6 Page 6A1–65
Page 6A1–65
Accessory Drive Belt Tensioner Diagnosis
Diagnostic Table
Step Action Yes No
1 1 Remove the accessory drive belt.
2 Inspect the drive belt tensioner pulley.
Is the drive belt tensioner pulley loose or misaligned? Go to Step 4 Go to Step 2
2 Rotate the drive belt tensioner.
Does the drive belt tensioner ro tate freely, without any unusual
resistance or binding? Go to Step 3 Go to Step 4
3 1 Using a suitable torque wrench, measure the torque required to
lift the drive belt tensioner off the stop.
2 Using a known good tensioner, m easure the torque required to
lift the drive belt tensioner off the stop.
Is the first torque reading within 10% of the second reading? Accessory drive belt
tensioner OK Go to Step 4
4 Replace the drive belt tensioner, refer to
3.7 Accessory Drive Belt Tensioner Assembly.
Is the repair complete? Accessory drive belt
tensioner OK —

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ISUZU KB P190 2007