Engine Mechanical – V6 Page 6A1–48
NOTE
Pilling is the small balls (pills) 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 diagnostic table completed, but the rumble is still present only when the drive
belt is installed, an accessory drive component such as the 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 diagnosis. 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 that it is not causing the noise. Small cracks across the ribs of the drive belt will not cause the noise and are not justification 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. W hen the pilling is severe (33% of the belt groove depth), the belt does not have a smooth 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 complaint. 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
4 Inspect the accessory drive belt for damage, separation or sections of missing ribs.
Did you find any damaged, separated or missing ribs? Go to Step 7 Go to Step 5
5 Inspect the accessory drive belt for severe pilling (exceeding 33% of the belt groove depth).
Did you find sever pilling? Go to Step 6 Go to Step 5
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ISUZU KB P190 2007
Engine Mechanical – V6 Page 6A1–49
Step Action Yes No
6 Clean the drive belt using a suitable wire brush and reinstall to the
engine, refer to 3.5 Accessory Drive Belt.
Did you complete the repairs? Go to Step 8 —
7 Install a new accessory drive belt, refer to 3.5 Accessory Drive Belt.
Did you replace the accessory drive belt? Go to Step 8
—
8 If required, reinstall the accessory drive belt and operate the system to
confirm the repair.
Did you correct the rumbling noise? Accessory drive
system OK Refer to Diagnostic
Aids in this Section
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 compressor 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 diagnosis. 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 incorrect fastener has been installed.
8 This step should only be performed if the 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, cracked or loose may put extra strain on the accessory component causing it to vibrate.
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ISUZU KB P190 2007
Engine Mechanical – V6 Page 6A1–50
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 complaint. 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 —
6 Inspect for incorrect, loose, missing or damaged fasteners. Did you find any incorrect, loose, missing or damaged fasteners? Go to Step 7 Go to Step 8
7 Tighten any loose fasteners to the correct torque specification, refer to
6 Torque W rench Specifications.
Replace any incorrect or missing fasteners.
Did you complete the repairs? Go to Step 10 —
8 Inspect the coolant pump for a bent shaft, refer to 6B1 Engine Cooling – V6.
Did you find and repair a bent coolant pump shaft? Go to Step 10 Go to Step 9
9 Inspect for bent, cracked or damaged accessory drive component mounting brackets.
Did you find and repair any bent brackets? Go to Step 10 Refer to Diagnostic
Aids in this Section
10 If required, reinstall the accessory drive belt and operate the system to
confirm the repair.
Did you correct the vibration? Accessory drive
system OK Refer to Diagnostic
Aids in this Section
Drive Belt Falls Off
Definition
The drive belt falls off during normal operation or does not ride correctly on the accessory drive pulleys.
Diagnostic Aids
If the accessory drive belt repeatedly falls off the drive pulleys, this is most likely due to pulley misalignment.
An extra load that is quickly applied and released by an accessory drive component (e.g. A/C compressor) may cause
the accessory drive belt to fall off. In this circumstance, confirm the fault by operating the accessory drive components in
turn, noting which one caused the belt to fall off.
Lack of drive belt tension may also cause the belt to fall off the pulleys. Low drive belt tension could be caused by one of
the following:
• an incorrect drive belt length,
• a faulty drive belt tensioner, or
• a stretched or faulty drive belt.
Test Description
The numbers below refer to steps in the diagnostic table.
2 Confirms the condition of the drive belt. Damage may have occurred to the drive belt when it first fell off or it may have been damaged which caused the belt to fall off.
4 Misalignment of the pulleys may be caused by:
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ISUZU KB P190 2007
Engine Mechanical – V6 Page 6A1–59
3.5 Accessory Drive Belt
RWD Vehicle
Remove
1 Remove the air intake duct from between the air flow meter and the throttle body, refer to 6C1-3 Engine
Management – V6 – Service Operations.
2 Note the accessory drive belt (1) routing.
Figure 6A1 – 29
3 Using a suitable ½” drive socket bar (1), rotate the drive belt tensioner (2) clockwise, to reduce belt
tension.
4 W hile holding the tensioner in the reduced tension position, remove the accessory drive belt (3).
NOTE
If required use an assistant to maintain the tensioner in the required position.
CAUTION
If 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.
Figure 6A1 – 30
Reinstall
1 Install the drive belt over the A/C compressor, idler pulley, power steering pump, coolant pump, generator and tensioner pulleys.
2 Using a suitable ½” drive socket bar (1), rotate the drive belt tensioner (2) clockwise, refer to Figure 6A1 – 30.
3 W ith an assistant holding the tensioner in the required position, feed the accessory drive belt (3) over the crankshaft pulley.
4 Slowly release the drive belt tensioner mechanism.
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ISUZU KB P190 2007
Engine Mechanical – V6 Page 6A1–77
12 Remove the three bolts (1), attaching the exhaust
manifold inner heat shield to the exhaust manifold.
13 Using a suitable commercially available non-corrosive cleaning solvent and a soft bristled parts cleaning
brush, thoroughly clean the exhaust manifold.
14 Dry the exhaust manifold using compressed air.
Safety glasses must be worn when using
compressed air.
Figure 6A1 – 59
NOTE
• The same procedure applies to the Right-
hand exhaust manifold.
• To gain access to the lower rear exhaust
manifold attaching bolts (2), apply a slight
downward movement to the coolant inlet
pipe (1).
Inspect
Inspect the exhaust manifold (1) for the following:
• Damage to the threaded holes for the heat shield
mounting.
• Damage to the exhaust manifold mounting holes.
• Damage to the threads of the exhaust manifold to
exhaust pipe flange studs.
• Damage to the gasket sealing surfaces.
• Using a straight edge (2) and feeler gauges (3), check
the cylinder head mounting face of the exhaust
manifold does not exceed the maximum distortion
specification of 0.25mm.
NOTE
If the surface flatness is not within
specifications, the exhaust manifold is warped
and must be replaced.
Figure 6A1 – 60
Reinstall
Reinstallation of the exhaust manifold assembly is the reverse of the removal procedure, noting the following:
1 Ensure the exhaust manifold, cylinder head and exhaust pipe flange surfaces are clean.
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ISUZU KB P190 2007
Engine Mechanical – V6 Page 6A1–78
2 Position a new exhaust manifold gasket onto the exhaust manifold.
3 Apply a 5 mm bead of Loctite 272 thread sealant (or equivalent) to the threads of the exhaust manifold attaching bolts.
4 Install the bolts into the exhaust manifold. This will prevent the gasket from falling off the manifold.
5 Manoeuvre the exhaust manifold into position and install the exhaust manifold attaching bolts.
6 From underneath the vehicle install the exhaust manifold to exhaust pipe flange nuts.
7 Tighten the exhaust manifold attaching bolts to the correct torque specification.
NOTE
When tightening the exhaust manifold to cylinder
head attaching bolts, begin with the centre bolts,
then alternate from side to side to the outer bolts.
Exhaust manifold to cylinder head
attaching bolt torque specification ...........17.0 – 23.0 Nm
8 Apply an anti seize compound such as Caltex Kopr-Kote (or equivalent) to the cleaned heat shield bolt threads. Install the heat shield attaching bolts and tighten to the correct torque specification.
Exhaust manifold heat shield attaching
bolt torque specification ............................8.0 – 12.0 Nm
9 For the right-hand side, install the battery harness ground cable attaching nut through the ground terminal and lower coolant tube mounting lug, and tighten to the correct torque specification.
Battery harness ground terminal
attaching nut torque specification.......................13.0 Nm
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ISUZU KB P190 2007
Engine Mechanical – V6 Page 6A1–80
6 Remove the bolt (1) attaching the ground connector
(2) to the cylinder head.
7 Fro the left-hand side, disconnect the engine coolant temperature (ECT) sensor wiring connector (3).
8 Unclip the engine wiring harness retaining lugs from the side of the camshaft cover.
Figure 6A1 – 63
9 For the right-hand side, remove the engine wiring harness retaining clip (1) from the engine control
module (ECM) bracket (2).
Figure 6A1 – 64
10 Disconnect the camshaft position (CMP) sensor wiring connector (1).
11 Unclip the engine wiring harness retaining lug (3) from the front of the camshaft cover.
12 Remove the ignition coil assemblies; refer to 6C1-3 Engine Management – V6 – Service Operations.
13 Move the engine wiring harness clear of the camshaft cover.
Figure 6A1 – 65
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ISUZU KB P190 2007
Engine Mechanical – V6 Page 6A1–87
3.14 Crankshaft Front Seal
Replace
1 Remove the crankshaft balancer assembly, refer to 3.13 Crankshaft Balancer Assembly.
2 Using a flat bladed tool (2) or seal remover, Tool No. E-308, carefully remove the crankshaft front seal (1)
from the front cover.
Figure 6A1 – 81
3 Using crankshaft front seal installer, Tool No. J-29184 (2) and a suitable hammer, install a new crankshaft
front seal (1) until fully seated against the front cover
housing.
4 Install the crankshaft balancer assembly, refer to 3.13 Crankshaft Balancer Assembly.
CAUTION
Do not lubricate the crankshaft front oil seal
or crankshaft balancer sealing surfaces. The
crankshaft balancer is installed into a dry
seal.
Figure 6A1 – 82
3.15 Front Cover Assembly
Remove
1 Drain the engine coolant, refer to 6B1_Engine Cooling.
2 Remove the water outlet pipe and coolant pump assembly, refer to 6B1_ Engine Cooling:
3 Remove the camshaft covers, refer to 3.12 Camshaft Cover.
4 Remove the crankshaft balancer assembly, refer to 3.13 Crankshaft Balancer Assembly.
5 Disconnect the purge vent hose from the water outlet pipe.
NOTE
Do not disconnect the power steering pipes or
drain the power steering fluid.
6 Remove the power steering pump reservoir mounting bracket, refer to 3.8 Power Steering Pump Bracket.
7 Remove the camshaft position sensor, refer to 6C1-3 Engine Management – V6 – Service Operations.
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ISUZU KB P190 2007