Engine Mechanical – V6 Page 6A1–38
Page 6A1–38
2.8 Engine Noise on Start-up, but only
Lasting a Few Seconds
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 t he 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
Oil filter anti-drain back valve faulty. Replace the o il filter adaptor, refer to 3.3 Oil Filter Adaptor.
Incorrect oil viscosity.
Drain the engine oil and replace with the correct viscosity
oil, refer to 3.1 Engine Oil.
High camshaft stationary hydraulic lash adjuster (SHLA)
leak down rate. Replace the SHLA as required,
refer to 3.21 Stationary
Hydraulic Lash Adjuster.
Worn crankshaft thrust bearing. Inspect and replace the crankshaft and/or bearings as
required, refer to 4.6 Crankshaft and Main Bearings.
Damaged or faulty oil filter by-pass valve. 1 Inspect the oil filter by-pass valve for correct
operation.
2 Repair or replace the oil filter adaptor/by-pass valve
as required.
BACK TO CHAPTER INDEX
TO MODEL INDEX
ISUZU KB P190 2007
Engine Mechanical – V6 Page 6A1–39
Page 6A1–39
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 t he 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.
Worn 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 t he 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, refe r 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.
Worn 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.
Worn camshaft lobes. Replace the camshaft/s and SHLAs as required, refer to
3.19 Camshaft or 3.21 Stati onary Hydraulic Lash Adjuster.
Worn 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.
BACK TO CHAPTER INDEX
TO MODEL INDEX
ISUZU KB P190 2007
Engine Mechanical – V6 Page 6A1–40
Page 6A1–40
2.10 Lower 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 t he 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.
Worn accessory drive components.
Abnormalities such as severe cracking, bumps, stretching
or missing areas on an accessory drive belt and/or
misalignment of accessory drive system components. Inspect the accessory drive system, repair or replace
components as required, refer to 3.5 Accessory Drive Belt.
Loose or damaged crankshaft balancer and pulley
assembly. Repair or replace the crankshaft balancer and pulley
assembly as required, refer to 3.13 Crankshaft Balancer
Assembly.
Detonation or spark knock. Confirm the correct operation of the ignition system, refer to
6C1-2 Engine Management – V6 – Diagnostics.
Loose torque converter bolts. Inspect and tighten the torque converter bolts to the correct
torque specification, refer to 7C4 Automatic Transmission –
4L60E – On-vehicle Servicing.
Loose or damaged flexplate. Repair or replace the flexplate as required, refer to 4.3
Flexplate Assembly.
Oil pump suction pipe loos e, damaged or restricted.
Clean, inspect and repair/replace the oil pump suction pipe
as required, refer to 4.2 O il Pan and Oil Pump Suction Pipe
Assembly.
Excessive piston-to-cylinder bore clearance. Inspect the piston and cylinder bore and repair/replace
components as required, refer to 4.5 Pistons, Pins, Rings,
Connecting Rods and Big-end Bearings and 4.7 Cylinder
Block.
Excessive connecting rod bearing clearance. Inspect the connecting rod, crankshaft and bearings and
repair/replace components as required, refer to 4.5
Pistons, Pins, Rings, Connecting Rods and Big-end
Bearings and 4.6 Crankshaft and Main Bearings.
Excessive piston pin to bore clearance. Inspect the pistons and pins and repair/replace components
as required, refer to 4.5 Pistons, Pins, Rings, Connecting
Rods and Big-end Bearings.
Excessive crankshaft main bearing clearance. Inspect the crankshaft, cylinder block journals, main
bearings and main bearing caps and repair/replace
components as required, refer to 4.6 Crankshaft and Main
Bearings and 4.7 Cylinder Block.
Incorrect piston, pin and c onnecting rod installation.
Pistons must be installed with the mark or dimple facing the
front of the engine. Piston pi ns must be centred in the
piston pin bore. Confirm the pistons, pins and
connecting rods are installed
correctly and repair if required, refer to 4.5 Pistons, Pins,
Rings, Connecting Rods and Big-end Bearings.
BACK TO CHAPTER INDEX
TO MODEL INDEX
ISUZU KB P190 2007
Engine Mechanical – V6 Page 6A1–41
Page 6A1–41
2.11 Engine Noise Under Load
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 t he 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.
Detonation or spark knock. Confirm the correct operation of the ignition system, refer to
6C1-2 Engine Management – V6 – Diagnostics.
Loose torque converter bolts. Inspect and tighten the torque converter bolts to the correct
torque specification, refer to 7C1 Automatic – 4L60E –
General Information – 4L60E – General Information.
Cracked flexplate. Replace the flywheel/flex-plate as required, refer to
4.3 Flexplate Assembly.
Excessive connecting rod bearing clearance. Inspect the connecting rod, crankshaft and bearings and
repair/replace components as required, refer to
4.5 Pistons, Pins, Rings, Connecting Rods and Big-end
Bearings and 4.6 Crankshaft and Main Bearings.
Excessive crankshaft bearing clearance Inspect the crankshaft, cylinder block journals, main
bearings and main bearing caps and repair/replace
components as required, refer to 4.6 Crankshaft and Main
Bearings and 4.7 Cylinder Block.
BACK TO CHAPTER INDEX
TO MODEL INDEX
ISUZU KB P190 2007
Engine Mechanical – V6 Page 6A1–42
Page 6A1–42
2.12 Engine Will Not Crank – Crankshaft Will
Not Rotate
Cause Correction
Seized accessory drive system component. 1 Remove the accessory drive belt, refer to
3.5 Accessory Drive Belt.
2 Rotate the crankshaft by hand at the balancer pulley or flywheel.
3 Repair or replace accessory drive system components as required.
Hydraulically locked cylinder caused by:
• coolant in cylinder,
• oil in cylinder, or
• fuel in cylinder. 1 Remove the spark plugs and check for fluid, refer to
6C1-3 Engine Management – V6 – Service
Operations.
2 Inspect for broken head gasket/s.
3 Inspect for cracked engine block or cylinder head.
4 Inspect for sticking fuel injector.
5 Repair or replace components as required.
Seized torque converter. 1 Remove the torque converter bolts, refer to 7C1
Automatic – 4L60E – General Information – 4L60E –
General Information.
2 Rotate the crankshaft by hand at the balancer pulley or flywheel.
3 Repair or replace torque converter as required.
Material in cylinder bore, caused by:
• broken valve,
• broken piston or ring, or
• dirt or foreign matter entry during engine assembly
procedure. 1 Clean and inspect the cylinder for damaged
components and or foreign matter, refer to 4.7
Cylinder Block.
2 Repair or replace components as required.
Seized crankshaft or connecting rod bearings. Inspect and repair or replace crankshaft, connecting rod
and bearings as required, refer to 4.5 Pistons, Pins, Rings,
Connecting Rods and Big-end Bearings and 4.6
Crankshaft and Main Bearings.
Bent or broken connecting rod. Inspect and repair or replace connecting rod and bearings
as required, refer to 4.5 Pistons, Pins, Rings, Connecting
Rods and Big-end Bearings.
Bent or broken crankshaft. Inspect and repair or replace crankshaft and bearings as
required, refer to 4.6 Crankshaft and Main Bearings.
Seized or broken camshaft. 1 Inspect and replace camshafts as required, refer to
3.19 Camshaft.
2 Inspect camshaft journals and cam caps on cylinder head and repair or replace components as required,
refer to 3.22 Cylinder Head Assembly.
Seized or broken camshaft timing components. 1 Inspect the crankshaft, idler, intake camshaft and
exhaust camshaft sprockets.
2 Inspect the timing chains.
3 Inspect the guides.
4 Inspect the tensioners.
5 Repair or replace components as required, refer to 3.16 Timing Chains, Tensioners, Shoes and Guides.
Seized or broken valve train components. 1 Inspect the stationary hydraulic lash adjusters, refer
to 3.21 Stationary Hydraulic Lash Adjuster.
2 Inspect the rocker arms, re fer to 3.20 Rocker Arm.
3 Inspect the Valves Refer to 3.22 Cylinder Head Assembly.
4 Inspect the valve springs, refer to 3.22 Cylinder Head Assembly.
5 Repair or replace components as required.
BACK TO CHAPTER INDEX
TO MODEL INDEX
ISUZU KB P190 2007
Engine Mechanical – V6 Page 6A1–44
Page 6A1–44
2.14 Coolant in Engine Oil
Definition
Foamy or discoloured oil or an engine oil overfill condition may indicate coolant entering the engine crankcase. Low
coolant levels, an inoperative engine cooli ng fan or a faulty thermostat may lead to an over-temperature condition which
may result in engine component damage. Contaminat ed engine oil and oil filters must be replaced.
1 Inspect the oil for excessive foaming or an overfill condition. Oil diluted by coolant may not correctly lubricate the
crankshaft bearings, resulting in component damage, refer to 2.10 Lower Engine Noise, Regardless of Engine
Speed .
2 Perform a cylinder leakage test, refer to 2.16 Cylinder Leakage Test. During this procedure, excessive air bubbles
in the engine coolant may indicate a faulty gasket or damaged component.
3 Perform a cylinder compression test. Two cylinders side-by -side on the cylinder block, with low compression, may
indicate a failed cylinder head gasket, refer to 2.15 Engine Compression Test.
Cause Correction
Faulty cylinder head gasket. Replace the cylinder head gasket, refer to 3.22 Cylinder
Head Assembly.
Warped cylinder head. Repair or replace the cylinder heads as required, refer to
3.22 Cylinder Head Assembly.
Cracked cylinder liner or block Repair or replace the cylinder block and components as
required, refer to 4.7 Cylinder Block.
Cylinder head, cylinder block or intake manifold porosity. Repair or replace the cylinder block, cylinder heads or
intake manifold components as required, refer to
4.7 Cylinder Block, 3.22 Cylinder Head Assembly or
3.10 Intake Manifold Assembly – Complete.
BACK TO CHAPTER INDEX
TO MODEL INDEX
ISUZU KB P190 2007
Engine Mechanical – V6 Page 6A1–45
Page 6A1–45
2.15 Engine Compression Test
A compression pressure test of the engine cylinders determines the condition of the rings, the valves and the head
gasket.
Preliminary Steps
1 Ensure the battery is fully charged.
2 Remove the spark plugs from all cylinders, refer to Section 6C1-3 Engine Management – V6 – Service Operations.
NOTE
DTCs will set when the fuel system or the ignition
system is disabled and the engine is cranked.
Disregard DTCs that set under this condition.
3 Disable the fuel system by removi ng the fuel pump relay, refer to Section 8A Electrical Body & Chassis .
4 Start the engine to use any resi dual fuel from the fuel lines.
4 Disable the ignition coils by removing fuses 34 and 35, refer to Section 8A Electrical Body & Chassis .
5 Using Tech 2, command the throttle plate to wide open throttle.
Engine Cylinder Compression Test
1 Install the compression tester to cylinder number 1.
2 While observing the compression tester reading, turn t he ignition to the START position for several seconds and
then allow the ignition to return to the ON position.
3 Record the highest compression reading obtained.
4 Repeat the engine compression test for each cylinder.
Test Result Evaluation
Normal engine compression pressure builds quickly and evenly to over 965 kPa. In addition, the lowest reading of an
engine cylinder should not be less than 70 per cent of the highest reading. If any cylinder fails the compression test,
adding 15 ml of engine oil to the suspected cylinder may help isolate the following fault condition.
1 A fault condition in the piston rings will produce the following result:
• A low compression on the first engine cycle
• The compression tends to build-up with the succeeding engine rotation.
• The compression improves with the addition of engine oil.
2 A fault condition in an intake or exhaus t valve will produce the following result:
• A low compression on the first engine cycle
• The compression does not build with the succeeding engine rotation.
• The compression does not improve with the addition of engine oil.
3 A fault condition in the cylinder head gasket will produce the following result:
• A low compression on the first engine cycle
• The compression does not build with the succeeding engine rotation.
• The compression does not improve with the addition of engine oil.
• The suspected cylinders are pos itioned adjacent to each other.
• The engine oil may be contaminated with engine coolant.
• The engine coolant may be cont aminated with engine oil.
Once the fault has been identified, refe r to the relevant service procedure and reinstall the removed components.
Using Tech 2, clear DTCs.
BACK TO CHAPTER INDEX
TO MODEL INDEX
ISUZU KB P190 2007
Engine Mechanical – V6 Page 6A1–46
Page 6A1–46
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 Section 6C1-3 Engine Management – V6 – Service Operations.
3 Rotate the crankshaft to place the piston in the cyli nder 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 dow n tester and adjust according to the manufacturers
instructions.
6 Record the cylinder leakage value. Cylinder leakage t hat 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 rema ining cylinders and record the values.
BACK TO CHAPTER INDEX
TO MODEL INDEX
ISUZU KB P190 2007