Engine Mechanical – V6 Page 6A1–39
2.16 Cylinder Leakage Test
A leakage test may be performed to measure cylinder/combustion chamber leakage. High cylinder leakage may indicate
one or more of the following:
• worn or burnt valves,
• broken valve springs,
• stuck valve lifters,
• incorrect valve lash/adjustment,
• damaged piston,
• worn piston rings,
• worn or scored cylinder bore,
• damaged cylinder head gasket,
• cracked or damaged cylinder head, or
• cracked or damaged engine block.
1 Disconnect the battery ground negative cable.
2 Remove the spark plugs from all cylinders, refer to 6C1-3 Engine Management – V6 – Service Operations.
3 Rotate the crankshaft to place the piston in the cylinder being tested at top dead centre (TDC) of the compression stroke.
4 Install a commercially available cylinder head leak down tester into the spark plug hole.
NOTE
If required, hold the crankshaft balancer bolt to
prevent the engine from rotating.
5 Apply shop air pressure to the cylinder head leak down tester and adjust according to the manufacturers instructions.
6 Record the cylinder leakage value. Cylinder leakage that exceeds 25 percent is considered excessive and may require component service. In excessive leakage situations, inspect for the following conditions:
• air leakage sounds at the throttle body or air inlet duct that may indicate a worn or burnt intake valve or a
broken valve spring,
• air leakage sounds at the exhaust system tailpipe that may indicate a worn or burnt exhaust valve or a broken
valve spring,
• air leakage sounds from the crankcase, oil level indicator tube, or oil fill tube that may indicate worn piston
rings, a damaged piston, a worn or scored cylinder bore, a damaged engine block or a damaged cylinder
head, or
• air bubbles in the cooling system may indicate a damaged cylinder head or a damaged cylinder head gasket.
7 Perform the leakage test on the remaining cylinders and record the values.
2.17 Engine Oil Consumption Diagnosis
Definition
Excessive oil consumption (not due to leaks) is the use of 3 litres or more of engine oil within 10,000 kilometres. Prior to
performing oil pressure testing, a preliminary inspection of the vehicle should be performed. During the preliminary visual
inspection, the following likely causes of excessive oil usage should be investigated.
Cause Correction
External oil leaks. Refer to 2.18 Engine Oil Leak Diagnosis.
Incorrect oil level or reading of the oil level indicator. Check for the correct oil level, refer to 3.1 Engine Oil.
Incorrect oil viscosity. Replace the engine oil, using the recommended SAE grade
of engine oil, refer to 3.1 Engine Oil.
Continuous high-speed driving or severe usage. Service vehicle more frequently, refer to 0B Lubrication and
Service.
Crankcase ventilation system restricted or malfunctioning. Repair or replace crankcase ventilation system components as required, refer to 6C1-3 Engine Management – V6 –
Service Operations.
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Engine Mechanical – V6 Page 6A1–40
Cause Correction
W orn valve guides and or valve stems. Inspect and repair valves and valve guides as required,
refer to 3.22 Cylinder Head Assembly.
W orn or damaged valve stem oil seal. Replace valve stem oil seals as required, refer to 3.22
Cylinder Head Assembly.
Piston rings broken, worn or not seated correctly. Allowing adequate time for the piston rings to seat correctly,
replace piston rings as required, refer to 4.5 Pistons, Pins,
Rings, Connecting Rods and Big-end Bearings.
Piston rings incorrectly installed or not matched to cylinder
bore oversize. Replace piston rings as required, refer to 4.5 Pistons, Pins,
Rings, Connecting Rods and Big-end Bearings.
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 valley 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 repairing or replacing the faulty component or resealing the gasket surface. However,
once a leak is identified it is important to determine and repair the cause as well as the leak itself.
Locating and Identifying the Leak
Inspect the leaking fluid and determine whether 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.
W hen performing the visual inspection:
1 Bring the vehicle to the normal operating temperature.
2 Park the vehicle over a large sheet of paper or other clean surface.
3 Leave the vehicle idling for 2-3 minutes, then check for dripping fluid.
4 If required, identify the type of fluid leaking 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 kilometres 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 entire engine and surrounding components.
2 Apply an aerosol type powder (e.g. foot 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 viewing 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 available equivalent is available to technicians to aid in
engine oil leak diagnosis. W hen using a black light and die kit for 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.
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ISUZU KB P190 2007
Engine Mechanical – V6 Page 6A1–41
3 W ith the vehicle parked on a flat level 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.
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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Engine Mechanical – V6 Page 6A1–42
2.19 Engine Oil Pressure Diagnosis
If the engine oil pressure is below the specified value, inspect the engine and components for the following:
• loose oil filter adaptor bolts,
• faulty oil filter adaptor seals,
• worn or faulty oil pump,
• loose oil pump bolts,
• loose, blocked or damaged oil pump suction pipe,
• faulty oil pump suction pipe seal,
• faulty oil pump pressure relief valve,
• faulty or incorrectly installed oil gallery plugs,
• excessive bearing clearance in one of the following:
• connecting rods big end/s,
• crankshaft main journal/s,
• camshaft/s,
• camshaft sprocket/s, and
• cracked, porous or restricted oil galleries, or broken lash adjuster/s.
2.20 Accessory Drive Belt Diagnosis
Tension Check
NOTE
An accessory drive belt that squeaks when the
engine is started or stopped is considered normal
and has no effect on drive belt durability.
1 Start the engine and switch off the air-conditioning system. Allow engine to run until normal operating temperature has been reached.
2 Turn the engine off and inspect the markings on the drive belt tensioner to confirm the drive belt tension is
within the operating limits.
3 If the markings on the drive belt tensioner were outside the acceptable operating limits, replace the
accessory drive belt, refer to 3.5 Accessory
Drive Belt.
NOTE
The operating limits for acceptable drive belt
tension are when the drive belt tensioner pointer
(1) is aligned between the outer edge of the
minimum and maximum tension marks (2).
Figure 6A1 – 21
Inspect
Figure 6A1 – 22 illustrates the various stages of belt wear to aid in belt replacement decisions. Condition of the belt ribs
is best judged where the belt is bent over one of the larger accessory drive system pulleys.
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ISUZU KB P190 2007
Engine Mechanical – V6 Page 6A1–53
3 Minor Service Operations
ATTENTION
The V6 engine is a combination of numerous components, containing machined, honed, polished and lapped
surfaces manufactured on the latest, high technology production equipment. Many of the components
contain tolerances measured in thousandths of a millimetre. Consequently, when any engine component is to
be serviced, care and cleanliness are extremely important.
Prior to re-assembly of the engine, all components must be cleaned and inspected in accordance with the
relevant clean and inspect procedures throughout this Section, and replaced or repaired where required.
In addition to cleaning and inspecting components, a liberal coating of engine oil should be applied to friction
surfaces during assembly to protect and lubricate the surfaces on initial operation.
When performing any service operation, it should be understood that correct cleaning and protection of
machined surfaces and friction areas is part of the repair procedure. This is considered standard workshop
practice, even if not specifically stated. Torque values must be used as specified during reassembly to
ensure correct retention of all components.
Through out this section, fastener torque wrench specifications may be accompanied with the following
identification marks:
■ Fasteners must be replaced after loosening.
Fasteners either have micro encapsulated sealant applied or incorporate a mechanical thread lock and
should only be re-used once. If in doubt, replacement is recommended.
If one of these identification marks is present alongside a fastener torque wrench specification, the
recommendation regarding that fastener must be adhered to.
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Engine Mechanical – V6 Page 6A1–54
3.1 Engine Oil
The procedure outlined below is typically the same for both rear wheel drive and all wheel drive vehicles.
Check
The following procedure is applicable to both rear wheel and all wheel drive vehicles
1 Run the engine to bring it to normal operating temperature.
2 Park the vehicle on a level surface. A vehicle that is not level will affect the accuracy of the level reading.
3 Stop the engine and wait 5 to 10 minutes to allow the oil to drain back into the oil pan.
4 Remove the oil level indicator (1) and wipe clean.
5 Insert the indicator, ensuring it is fully seated.
6 Slowly remove the indicator to avoid smearing. Hold it horizontally or with lower end slightly down to avoid
oil running along indicator.
7 Observe the oil level where it passes over the centre line of the indicator.
8 If the level is lower than the Add mark (2), add enough oil to the engine to reach the Upper mark (3).
Do not add too much oil as the reading should never
be above the Upper mark.
NOTE
When topping up the oil, allow approximately 5
to 10 minutes for the added oil to fully drain into
the oil pan.
Figure 6A1 – 23
Replace
NOTE
• Quicker and more complete draining will
occur if the engine oil is at normal operating
temperature. However, care must be taken to
avoid scalding from the hot oil.
• It recommended the oil filter be changed at
each engine oil change, refer to 3.2 Oil
Filter.
1 Remove the oil fill cap.
2 To ensure complete draining of the oil pan, raise the front and rear of the vehicle to maintain a level attitude. If not using a hoist, support the vehicle with safety stands, refer to 0A General Information.
3 Clean any foreign material from around the oil drain plug and place a suitable, clean drain tray under the engine.
The oil may be hot. Avoid contact with the oil.
Ensure that eyes and skin are protected.
4 Remove the drain plug (1), taking care to avoid scalding from the hot oil. Allow the oil to drain.
5 Clean and inspect the drain plug threads. If damaged, replace the drain plug.
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Engine Mechanical – V6 Page 6A1–55
Figure 6A1 – 24
6 Once the oil has completely drained, reinstall the drain plug and tighten to the correct torque specification.
Oil pan drain plug
torque specification ............................................25.0 Nm
7 Replace the oil filter, refer to 3.2 Oil Filter.
8 Lower the vehicle to the ground and fill with the specified amount of SAE 5W 30 lubricant.
Engine Oil Capacity:
With Oil Filter Change ........................................6.5 litres
9 Install the oil fill cap.
10 Start the engine and check for leaks.
Pressure Check
1 Run the engine to bring it to normal operating temperature.
2 Park the vehicle on a level surface. A vehicle not level will affect the accuracy of the level reading.
3 Stop the engine and wait 5 to 10 minutes to allow the oil to drain back into the oil pan.
4 Check the oil level and top up with the recommended engine oil as required, refer to Check, in this Section.
5 Remove the engine oil pressure sensor (1), refer to 6C1-3 Engine Management – V6 – Service
Operations.
6 Install the oil pressure gauge adaptor, Tool No. J36648-A into the oil pressure sender hole in the oil
filter housing.
7 Install a suitable oil pressure gauge into the adaptor.
8 Start the engine.
9 Measure and record the pressure reading on the gauge at idle and 2000 r.p.m. Compare the results
with the specification.
Minimum engine oil pressure
@ idle................................................................... 69 kPa
@ 2000 r.p.m. .................................................... 138 kPa
10 If the engine oil pressure is not to specification, refer to 2.19 Engine Oil Pressure Diagnosis.
11 After completing the engine oil pressure check, stop the engine and remove the oil pressure gauge.
Figure 6A1 – 25
12 Reinstall the oil pressure sensor, refer to 6C1-3 Engine Management – V6 – Service Operations.
13 Start the engine and check for leaks.
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Engine Mechanical – V6 Page 6A1–56
3.2 Oil Filter Cartridge
Replace
NOTE
• The oil filter cartridge should be replaced at
the correct time or distance intervals, refer to
0B Lubrication and Service.
• The oil filter cartridge should also be replaced
whenever the engine oil is suspected to have
been contaminated by foreign material.
1 Remove and discard the oil filter cartridge (1).
2 Install the new oil filter cartridge.
Figure 6A1 – 26
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