Isuzu KB P190. Manual — part 626

Engine Mechanical – V6

Page 6A1–25

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Do not use any other method or technique to remove sealant or gasket material from a part.

•

Do not use abrasive pads, sand paper, or power tools to clean the gasket surfaces as these methods of cleaning
can cause damage to the component sealing surfaces. Abrasive pads also produce fine grit that the oil filter cannot
remove from the oil. This grit is abrasive and has been known to cause internal engine damage.

Assembling Components

•

When assembling components, use only the sealant specified or equivalent in the service procedure.

•

Sealing surfaces should be clean and free of debris or oil.

•

Specific components such as crankshaft oil seals or valve stem oil seals may require lubrication during assembly.

•

Components requiring lubrication will be identified in the service procedure.

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When applying sealant to a component, apply the amount specified in the service procedure.

•

Do not allow the sealant to enter into any blind threaded holes as it may prevent the bolt from clamping correctly or
cause component damage when tightened.

•

Only ever tighten bolts to the correct torque specification. Do not over-tighten.

Use of Room Temperature Vulcanising and Anaerobic Sealer

CAUTION

A number of sealant types are commonly
used in engines. Examples are; room
temperature vulcanising (RTV) sealer,
anaerobic gasket eliminator sealer, and
anaerobic thread sealant and pipe joint
compound. The correct type of sealant and
amount must be used in the specified location
to prevent oil leaks. Do not interchange the
different types of sealers.

Room Temperature Vulcanising Sealer

•

Room temperature vulcanising (RTV) sealant hardens when exposed to air. This type of sealer is used where two
non-rigid parts (such as the intake manifold and the engine block) are assembled together.

•

Do not use RTV sealant in areas where extreme temperatures are experienced. These areas include the exhaust
manifold, head gasket, or other surfaces where a gasket eliminator is specified.

•

Follow all safety recommendations and directions that are on the container.

•

To remove the sealant or the gasket material, refer to Replacing Engine Gaskets.

•

Apply RTV to a clean surface. Use a bead size as specified in the service procedure. Run the bead to the inside of
any bolt holes. Do not allow the sealer to enter any blind threaded holes, as it may prevent the bolt from clamping
correctly or cause damage when the bolt is tightened.

•

Assemble components while RTV is still wet (within 3 minutes). Do not wait for RTV to skin over.

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Tighten the bolts to the correct torque specification. Do not over-tighten.

Anaerobic Sealer

•

Anaerobic gasket eliminator or thread sealant, hardens in the absence of air. This type sealer is used where two
rigid parts (such as castings) are assembled together, where fasteners are subjected to vibration, or where the
holes are not blind. When two rigid parts are disassembled and no sealer or gasket is readily noticeable, the parts
were probably assembled using a gasket eliminator.

•

Follow all safety recommendations and directions that are on the container.

•

To remove the sealant or the gasket material, refer to Replacing Engine Gaskets.

•

Apply a continuous bead of gasket eliminator to one flange or on the bolt/stud thread. All surfaces must be clean
and dry.

•

Spread the sealer evenly to achieve a uniform coating on the sealing surface.

•

Do not allow the sealer to enter any blind threaded holes as it may prevent the bolt from clamping correctly or
cause damage when tightened.

Engine Mechanical – V6

Page 6A1–26

CAUTION

Anaerobic sealed joints that are partially
tightened and allowed to cure more than five
minutes may result in incorrect shimming and
sealing of the joint.

•

Tighten the bolts to the correct torque specification. Do not over-tighten.

•

After correctly tightening the fasteners, remove the excess sealer from the outside of the joint.

Pipe Joint Compound

•

Pipe joint compound is a pliable sealer that does not completely harden. This type of sealer is used where two non-
rigid parts (such as pressed steel and machined surfaces) are assembled together.

•

Do not use pipe joint compound in areas where extreme temperatures are expected. These areas include the
exhaust manifold, head gasket, or other surfaces where gasket eliminator is specified.

•

Follow all safety recommendations and directions that are on the container.

•

To remove the sealant or the gasket material, refer to Replacing Engine Gaskets.

•

Apply the pipe joint compound to a clean surface. Use a bead size or quantity as specified in the procedure. Run
the bead to the inside of any bolt holes. Do not allow the sealer to enter any blind threaded holes as it may prevent
the bolt from clamping correctly or cause component damage when the bolt is tightened.

•

Apply a continuous bead of pipe joint compound to one sealing surface. Sealing surfaces to be resealed must be
clean and dry.

•

Tighten the bolts to the correct torque specification. Do not over-tighten.

Separating Parts

CAUTION

Many internal engine components will
develop specific wear patterns on their
friction surfaces. When disassembling the
engine, internal components must be
separated, marked and organised in a way to
ensure reinstallation in their original location
and position.

Separate, mark, or organise the following components:
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Piston and the piston pin.

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Piston to the specific cylinder bore.

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Piston rings to the specific piston.

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Connecting rod to the crankshaft journal.

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Connecting rod to the bearing cap.

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Crankshaft main and connecting rod bearings.

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Camshaft and rocker arms.

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Rocker arms and stationary hydraulic lash adjusters to cylinder head location.

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Valve to the valve guide.

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Valve spring and shim to the cylinder head location.

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Engine block main bearing cap location and direction.

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Oil pump drive and driven gears.

Tools and Equipment

Special tools are listed and illustrated throughout this Section with a complete listing at the end, refer to 7

Special

Tools. These tools (or their equivalents) are specially designed to quickly and safely accomplish the operations for which
they are intended. The use of these special tools will also minimise possible damage to engine components. Some
precision measuring tools are required for inspection of certain critical components. A commercially available torque
wrench and torque angle wrench, Tool No. EN-7115 are required for the correct tightening of various fasteners.

To correctly service the engine assembly, the following items should be readily available:
•

Approved eye protection and safety gloves.

Engine Mechanical – V6

Page 6A1–27

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A clean, well-lit, work area.

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A suitable parts cleaning tank.

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A compressed air supply.

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Trays or storage containers to keep parts and fasteners organised.

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An adequate set of hand tools.

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Approved engine repair stand.

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An approved engine lifting device that will adequately support the weight of the components.

Fasteners

Fasteners are central to the reliable operation of an engine.
Whenever any bolt or any other threaded component is
removed, allow the engine to cool (inset A) before
attempting fastener removal.

Because of the greater thermal expansion of aluminium,
bolt threads will change dimension to a greater extent when
hot with this material (inset B) when compared to cast iron.

If a bolt or other threaded component is removed before the
engine is allowed to cool to at least 50

° C, threads could be

pulled from the cylinder block or cylinder head.

Do not use impact tools to remove bolts during engine
disassembly. While this may be common practice with cast
iron engine components, use of these tools is more likely to
pull the aluminium threads in the cylinder block or head of
this engine.

Figure 6A1 – 19

Clamp Load

When torque is applied to a fastener, the fastener stretches
and the joint compresses. The force developed in the
fastener due to its stretch is called tension (C), while the
force applied to the joint is called clamp load (B).

As shown, only a small portion of the applied torque (A) is
transferred to the clamp load (inset 1). Friction under the
bolt head (inset 3) and in the threads (inset 2) absorbs
much of the applied torque (A). Typically, only 10% (inset 1)
of the torque is available to develop stretch (or tension) in
the fastener and clamp load in the joint.

Therefore, a slight variation in friction in the thread or under
the bolt head, results in a wide variation in the clamp load
applied to the joint.

Figure 6A1 – 20

Torque Angle and Torque to Yield Fasteners

The torque angle method of applying torque to a fastener has been developed to overcome the effects of friction
variation in fastener applications.

The application of the torque angle method does not always mean the fastener has to be replaced after loosening. It is
only when the fastener has been angle tightened to the extent the yield point has been exceeded, that the fastener must
be replaced.

Examples are the main bearing caps that are angle tightened but the bolts can be re-used, whereas the M11 cylinder
head bolts that are torque to yield fasteners, must be replaced after loosening.

Engine Mechanical – V6

Page 6A1–28

2 Diagnosis

2.1

Engine Diagnosis

Begin engine mechanical system diagnosis by reviewing the disassembled views provided in 1.2 Engine Components
and 1.4 Engine Construction. Reviewing the description and operation information provided will assist in determining
whether the condition described by the customer is a fault or normal engine operation.

2.2 Symptoms

Strategy Based Diagnosis

1

Review the system operations to familiarise yourself with the system functions, refer to 1

General Information

and 6C1-1 Engine Management General Information.

2

Perform an engine management Diagnostic System Check, refer to 6C1-2 Engine Management – V6 – Diagnostics.

All diagnosis on a vehicle should follow a logical process. Strategy based diagnosis is a uniform approach for repairing
all vehicle systems. The strategy based diagnostic flow chart may always be used to resolve a system problem. The
diagnostic flow chart is the place to start when repairs are required. For a detailed explanation of strategy based
diagnosis and the flow chart, refer to 6C1-2 Engine Management – V6 – Diagnostics.

Visual / Physical Inspection

1

Inspect the vehicle for aftermarket accessories which may adversely affect engine operation.

2

Inspect the easily accessible or visible system components for obvious signs of damage or conditions that may
cause the symptom.

3

Check the engine lubrication system for the following:
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correct oil level,

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correct lubricant viscosity,

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correct oil filter application, and

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contaminated or burnt oil.

4

Confirm the exact operating conditions under which the fault occurs. Note factors such as:
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engine speed (r.p.m.),

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ambient temperature,

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engine temperature,

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engine warm-up time, and

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vehicle road speed.

5

Compare the engine sounds, if applicable, to a known good engine, and ensure you are not trying to diagnose a
normal operating condition.

Intermittent

For intermittent faults, test the vehicle under the same conditions the customer reported in order to confirm whether the
system is operating correctly.