Isuzu KB P190. Manual - part 704

Engine Mechanical – V6

Page 6A1–39

2.9

Upper Engine Noise, Regardless of
Engine Speed

N O T E

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 the 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.

Perform an oil pressure test, refer to 2.19 Engine Oil
Pressure Diagnosis.

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.

Clean, inspect and replace the camshaft lash
adjusters as required, refer to 3.21 Stationary
Hydraulic Lash Adjuster.

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 the 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, refer 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 Stationary 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.

Engine Mechanical – V6

Page 6A1–40

2.10 Lower Engine Noise, Regardless of

Engine Speed

N O T E

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 the 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.

Perform an oil pressure test, refer to 2.19 Engine Oil
Pressure Diagnosis.

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 loose, damaged or restricted.

Clean, inspect and repair/replace the oil pump suction pipe
as required, refer to 4.2 Oil 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 connecting rod installation.

Pistons must be installed with the mark or dimple facing the
front of the engine. Piston pins 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.

Engine Mechanical – V6

Page 6A1–41

2.11 Engine Noise Under Load

N O T E

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 the 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.

Perform an oil pressure test, refer to 2.19 Engine Oil
Pressure Diagnosis.

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.

Engine Mechanical – V6

Page 6A1–42

2.12 Engine Will Not Crank – Crankshaft Will

Not Rotate

Cause Correction

Seized accessory drive system component.

Remove the accessory drive belt, refer to
3.5 Accessory Drive Belt.

Rotate the crankshaft by hand at the balancer pulley
or flywheel.

Repair or replace accessory drive system
components as required.

Hydraulically locked cylinder caused by:
•

coolant in cylinder,

•

oil in cylinder, or

•

fuel in cylinder.

Remove the spark plugs and check for fluid, refer to
6C1-3 Engine Management – V6 – Service
Operations.

Inspect for broken head gasket/s.

Inspect for cracked engine block or cylinder head.

Inspect for sticking fuel injector.

Repair or replace components as required.

Seized torque converter.

Remove the torque converter bolts, refer to 7C1
Automatic – 4L60E – General Information – 4L60E –
General Information.

Rotate the crankshaft by hand at the balancer pulley
or flywheel.

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.

Clean and inspect the cylinder for damaged
components and or foreign matter, refer to 4.7
Cylinder Block.

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.

Inspect and replace camshafts as required, refer to
3.19 Camshaft.

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.

Inspect the crankshaft, idler, intake camshaft and
exhaust camshaft sprockets.

Inspect the timing chains.

Inspect the guides.

Inspect the tensioners.

Repair or replace components as required, refer to
3.16 Timing Chains, Tensioners, Shoes and Guides.

Seized or broken valve train components.

Inspect the stationary hydraulic lash adjusters, refer
to 3.21 Stationary Hydraulic Lash Adjuster.

Inspect the rocker arms, refer to 3.20 Rocker Arm.

Inspect the Valves Refer to 3.22 Cylinder Head
Assembly.

Inspect the valve springs, refer to 3.22 Cylinder Head
Assembly.

Repair or replace components as required.

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