compression ratio ISUZU KB P190 2007 Workshop Service Manual

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 6A1–288

5 Specifications
General
Engine Type.................................................................................................................... ..... V6
Bank Angle ..................................................................................................................... .... 60°
Displacement ............................................................................................ 3.6 litre (3,565 cm3)
Bore ........................................................................................................................... .... 94 mm
Stroke ......................................................................................................................... 85.6 mm
Compression Ratio ......................................................................................................... 10.2: 1
Cranking Speed at 40 °C .............................................................................................80 r.p.m.
Spark Plug Gap ............................................................................................................ 1.1 m m
Firing Order............................................................................................................. 1-2-3- 4-5-6
Cylinder Block
Cylinder Bore Diameter ........................................................................... 93.992 – 94.008 mm
Cylinder Out-of-Round – Production Maximum ........................................................ 0.013 mm
Crankshaft Main bearing bore Diameter .................................................. 72.867 – 72.881 mm
Cylinder Head Deck Surface Flatness ........................................................................ 0.05 mm
Crankshaft
Connecting Rod Journal Diameter ........................................................... 55.992 – 56.008 mm
Connecting Rod Journal Out-of-Round..................................................................... 0.005 mm
Connecting Rod Journal Taper ................................................................................ .0.005 mm
Connecting Rod Journal Width (Production)........................................................... 22.000 mm
Connecting Rod Journal Width (Service limit).......................................... 21.920 – 22.080 mm
Crankshaft End Play .................................................................................... 0.100 – 0.330 mm
Crankshaft Main Bearing Clearance ............................................................ 0.010 – 0.060 mm
Crankshaft Main Journal Diameter ......................................................... .67.992 – 68.008 mm
Crankshaft Main Journal Out-of-Round .................................................................... 0.005 mm
Crankshaft Main Journal Taper................................................................................ .0.005 mm
Crankshaft Main Journal Width, #2, 4 (Production) ....................................................... 24 mm
Crankshaft Main Journal Width, #2, 4 (Service)....................................... 23.900 – 24.100 mm
Crankshaft Main Journal Width, #3 (Production) .................................................... 24.400 mm
Crankshaft Main Journal Width, #3 (Service) .......................................... 24.360 – 24.440 mm
Crankshaft Main Journal Thrust Wall Runout .............................................. 0.000 – 0.040 mm
Crankshaft Main Journal Thrust Wall Square .............................................. 0.000 – 0.010 mm
Crankshaft Rear Flange Runout ............................................................................... 0.025 mm
Crankshaft Reluctor Ring Runout - Maximum........................................................... 1.500 mm
Crankshaft Thrust Bearing Clearance.......................................................... 0.076 – 0.305 mm
Crankshaft Thrust Surface Runout ........................................................................... 0.040 mm
Crankshaft Thrust Surface – Height Diameter ........................................................ 95.000 mm
Connecting Rod
Connecting Rod Length - Bore Centre-to-Centre.................................................. 150.400 mm
Connecting Rod Bore Diameter - Bearing End ........................................ 59.620 – 59.636 mm
Connecting Rod Bore Diameter - Pin End ............................................... 24.007 – 24.021 mm
Connecting Rod Width ........................................................................................... 21.775 mm
Connecting Rod Side Clearance.................................................................. 0.095 – 0.355 mm
Connecting Rod Bearing Clearance ............................................................ 0.010 – 0.070 mm
Piston
Piston Diameter ....................................................................................... 93.956 – 93.974 mm
Piston Pin Bore Diameter ........................................................................ 24.005 – 24.009 mm
Piston Ring Groove Width - First (Top) Compression Ring ......................... 1.220 – 1.240 mm
Piston Ring Groove Width - Second Compression Ring .............................. 1.510 – 1.530 mm

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Engine Mechanical – V6 Page 6A1–289

Piston Ring Groove Width - Oil Control Ring ............................................... 2.510 – 2.530 mm
Piston to Bore Clearance ............................................................................. 0.026 – 0.052 mm
Piston Pin
Piston Pin Diameter ..................................................................................23.997 - 24.000 mm
Piston Pin Length..................................................................................... 60.600 – 61.100 mm
Piston Pin Clearance to Connecting Rod Bore ............................................. 0.007 – 0.024mm
Piston Pin Clearance to Piston Pin Bore....................................................... 0.004 – 0.012mm
Piston Rings
Piston Ring to Groove Clearance:
• First (Top) Compression Ring............................................................... 0.030 – 0.065 mm
• Second Compression Ring ................................................................... 0.015 – 0.060 mm
• Oil Control Ring .................................................................................... 0.030 – 0.170 mm
Piston Ring End Gap:
• First (Top) Compression Ring............................................................... 0.150 – 0.300 mm
• Second Compression Ring ................................................................... 0.280 – 0.480 mm
• Oil Control Ring .................................................................................... 0.150 – 0.600 mm
Cylinder Head
Combustion Chamber Volume.................................................................................. 53.600 cc
Valve Guide Bore Diameter – Intake ........................................................... 6.000 – 6.020 mm
Valve Guide Bore Diameter – Exhaust ........................................................ 6.000 – 6.020 mm
Valve Guide Installed Height.................................................................... 14.050 – 14.550 mm
Stationary Hydraulic Lash Adjuster (SHLA) Bore Diameter ..................... 12.008 – 12.030 mm
Valve Seat Angle – Seating Surface ................................................................................... 45 °
Valve Seat Angle – Relief Surface ...................................................................................... 30 °
Valve Seat Angle – Undercut Surface ................................................................................ 60 °
Valve Seat Runout – Maximum ................................................................................ 0.050 mm
Valve Seat Width – Exhaust Seating Surface .............................................. 1.400 – 1.800 mm
Valve Seat Width – Exhaust Relief Surface ................................................. 0.700 – 0.900 mm
Valve Seat Width – Intake Seating Surface ................................................. 1.000 – 1.400 mm
Valve Seat Width – Intake Relief Surface .................................................... 0.500 – 0.700 mm
Engine Block Deck Surface Flatness .......................................................................... 0.05 mm
Exhaust Manifold Deck Surface Flatness ................................................................... 0.25 mm
Intake Manifold Deck Surface Flatness ...................................................................... 0.05 mm
Valve System
Face Angle..................................................................................................................... 44.25°
Face Runout ............................................................................................................. 0.038 m m
Valve Face Width – Exhaust..................................................................................... 2.750 mm
Valve Face Width – Intake ........................................................................................ 2.180 mm
Valve Head Diameter – Exhaust .............................................................. 30.470 – 30.730 mm
Valve Head Diameter – Intake ................................................................. 36.830 – 37.090 mm
Valve Installed Height .................................................................................. 35.26 – 36.69 mm
Valve Length – Exhaust .......................................................................................... 97.110 mm
Valve Length – Intake ........................................................................................... 101.230 mm
Valve Stem Diameter (standard).................................................................. 5.955 – 5.975 mm
Valve Stem Diameter (oversize) .................................................................. 6.013 – 6.033 mm
Valve Stem to Guide Clearance................................................................... 0.025 – 0.065 mm
Hydraulic Lash Adjuster Diameter ........................................................... 11.986 – 12.000 mm
Hydraulic Lash Adjuster to Bore Clearance ................................................. 0.037 – 0.041 mm
Rocker Arm/Camshaft Follower Ratio............................................................................. 1.68:1
Rocker Arm/Camshaft Follower Roller Diameter ..................................... 17.740 – 17.800 mm
Valve Spring Free Length ........................................................................ 42.500 – 45.500 mm

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ISUZU KB P190 2007

Engine Mechanical – V6 Page 6A1–2
Page 6A1–2
Visual / Physical Inspection ................................................................................................... .............................31
Intermittent ................................................................................................................... ........................................31
2.3 Engine Misfire without In ternal Engine Noises .................................................................................. ...............32
2.4 Engine Misfire with Abnormal In ternal Lower Engine Noises...................................................................... ....34
2.5 Engine Misfire with Abno rmal Valve Train Noise ................................................................................. .............35
2.6 Engine Misfire with Coolant Consumption ........................................................................................ ................36
2.7 Engine Misfire with E xcessive Oil Consumption .................................................................................. ............37
2.8 Engine Noise on Start-up, but only Lasting a Few Seconds ....................................................................... .....38
2.9 Upper Engine Noise, Rega rdless of Engine Speed................................................................................. ..........39
2.10 Lower Engine Noise, Rega rdless of Engine Speed ................................................................................. .........40
2.11 Engine Noise Under Load ................................................................................................................................... 41
2.12 Engine Will Not Crank – Crankshaft Will Not Rotate ............................................................................. ...........42
2.13 Coolant in Com bustion Chamber .................................................................................................. .....................43
Definition ..................................................................................................................... .........................................43
2.14 Coolant in Engine Oil........................................................................................................................................... 44
Definition ..............................................................................................................................................................44
2.15 Engine Compression Test........................................................................................................ ...........................45
Preliminary Steps................................................................................................................................................. 45
Engine Cylinder Compression Test ............................................................................................... ....................45
Test Result Evaluation ......................................................................................................... ...............................45
2.16 Cylinder Leakage Test .......................................................................................................... ...............................46
2.17 Engine Oil Consumption Diagnosis ............................................................................................... ....................47
Definition ..................................................................................................................... .........................................47
2.18 Engine Oil Leak Diagnosis .................................................................................................................................. 48
Introduction ..........................................................................................................................................................48
Locating and Identifying the Leak .............................................................................................. ........................48
Visual Inspection .............................................................................................................. ...................................48
Powder Method .................................................................................................................. ..................................48
Black Light and Dye Method ............................................................................................................................... 48
Possible Causes for Engine Oil Leaks ........................................................................................... ....................49
2.19 Engine Oil Pressu re Diagnosis .................................................................................................. .........................50
2.20 Accessory Drive Belt Diagnosis ................................................................................................. ........................51
Tension Check .................................................................................................................. ...................................51
Inspect ........................................................................................................................ ..........................................52
Drive Belt Chirp .................................................................................................................................................... 53
Definition ..................................................................................................................... .....................................53
Diagnostic Aids................................................................................................................................................. 53
Test Description ............................................................................................................... ................................53
Diagnostic Table............................................................................................................... ................................54
Drive Belt Squeal .............................................................................................................. ...................................55
Definition ..................................................................................................................... .....................................55
Diagnostic Aids................................................................................................................................................. 55
Test Description ............................................................................................................... ................................55
Diagnostic Table............................................................................................................... ................................55
Drive Belt Whine .................................................................................................................................................. 57
Definition ..................................................................................................................... .....................................57
Diagnostic Aids................................................................................................................................................. 57
Test Description ............................................................................................................... ................................57
Diagnostic Table............................................................................................................... ................................57
Drive Belt Rumble .............................................................................................................. ..................................58
Definition ..................................................................................................................... .....................................58
Diagnostic Aids................................................................................................................................................. 58
Test Description ............................................................................................................... ................................58
Diagnostic Table............................................................................................................... ................................58
Drive Belt Vibration........................................................................................................... ...................................60
Definition ..................................................................................................................... .....................................60
Diagnostic Aids................................................................................................................................................. 60
Test Description ............................................................................................................... ................................60
Diagnostic Table............................................................................................................... ................................60
Drive Belt Falls Off ........................................................................................................... ....................................62

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ISUZU KB P190 2007

Engine Mechanical – V6 Page 6A1–32
Page 6A1–32
2.3 Engine Misfire without Internal Engine
Noises
Cause Correction
Abnormalities, severe cracking, bumps or missing areas in
the accessory drive belt.
Abnormalities in the accessory drive system and/or
components may cause engine speed variations that result
in a misfire diagnostic trouble code (DTC). A misfire code
may be present without an ac tual misfire condition. Replace the accessory drive belt, refer to 3.5 Accessory
Drive Belt.
Refer to 6C1-2 Engine Management – V6 – Diagnostics to
check for DTCs.
Worn, damaged or misaligned accessory drive components
and excessive pulley run-out may lead to a misfire DTC.
A misfire code may be present without an actual misfire
condition. Inspect the components and repair or replace as required.
Refer to 6C1-2 Engine Management – V6 – Diagnostics to
check for DTCs.
Loose or incorrectly fitted flexplate or crankshaft balancer
assembly.
A misfire DTC may be present without an actual misfire
condition. Repair or replace the flexplat
e or crankshaft balancer as
required, refer to 3.13 Crankshaft Balancer Assembly or
4.3 Flexplate Assembly.
Refer to 6C1-2 Engine Management – V6 – Diagnostics to
check for DTCs
Restricted exhaust system.
A severe restriction in the exhaust flow can cause
significant loss of engine performance and may set a DTC.
Possible causes of restrict ions in the exhaust system
include collapsed/dented pipes and blocked mufflers and/or
catalytic converters. Repair or replace exhaust syst
em components as required,
refer to 8B Exhaust System.
Refer to 6C1-2 Engine Management – V6 – Diagnostics to
check for DTCs
Incorrectly installed or damaged vacuum hoses. Repair or replace vacuum hoses as required.
Incorrect sealing between the intake manifold and cylinder
heads, upper intake manifold and lower intake manifold,
throttle body and intake manifold. Repair or replace the intake
manifold, throttle body gaskets,
cylinder heads, throttle body as required.
Incorrectly installed or damaged barometric
pressure(BARO) sensor and/or seal. The seal should not
be torn or damaged. Repair or replace the BARO sensor and/or seal as
required, refer to 6C1-3 Engine Management – V6 –
Service Operations.
Incorrectly installed or damaged EVAP purge solenoid
and/or O-ring seal. Repair or replace the EVAP purge solenoid and/or seal as
required, refer to 6C1-3 Engine Management – V6 –
Service Operations
Worn or loose stationary hydraulic lash adjusters (SHLA)
and/or rocker arms.
The SHLAs, rocker arms and roller bearings should be
intact and in the correct position. Replace the SHLAs and/or rocker arms as required, refer to
3.21 Stationary Hydraulic Las h Adjuster or 3.20 Rocker
Arm.
Stuck valves.
Carbon build up on the valve stem s can result in the valves
not closing correctly. Repair or replace as required, refer to 3.22 Cylinder Head
Assembly.
Excessively worn or misaligned timing chain/s. Replace the timing chain/s and components 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.
Excessive oil pressure.
A lubrication system with ex cessive oil pressure may lead
to excessive lash adjuster pump-up and loss of
compression. 1 Perform an oil pressure tes
t, refer to 3.1 Engine Oil.
2 Repair or replace the engine oil pump as required, refer to 3.17 Oil Pump Assembly.

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Engine Mechanical – V6 Page 6A1–33
Page 6A1–33
Cause Correction
Faulty cylinder head gasket and/or cracking or other
damage to the cylinder head and cylinder block coolant
passages.
Coolant consumption may or may not cause the engine to
overheat. 1 Inspect the spark plugs for
coolant saturation, refer to
6C1-3 Engine Management – V6 – Service
Operations.
2 Inspect the cylinder heads, cylinder block and/or head gaskets, refer to 3.22 Cylinder Head Assembly
and/or 4.7 Cylinder Block.
3 Repair or replace components as required.
Worn piston rings.
Oil consumption may or ma y not cause the engine to
misfire. 1 Inspect the spark plugs for oil deposits, refer to 6C1-3
Engine Management – V6 – Service Operations.
2 Check the cylinders for a loss of compression, refer to 2.15 Engine Compression Test.
3 Perform compression testing to identify the cause of
low compression.
4 Repair or replace components as required.
A damaged crankshaft reluctor wheel.
A damaged crankshaft reluctor wheel can result in different
symptoms depending on the severity and location of the
damage.
Systems with severe relu ctor ring damage may exhibit
periodic loss of crankshaft posit ion, stop delivering a signal,
and then re-sync the crankshaft position.
Systems with slight reluctor ring damage may exhibit no
loss of crankshaft position and no misfire may occur,
however, a DTC may set. Replace the crankshaft as required, refer to 4.6 Crankshaft
and Main Bearings.
Refer to 6C1-2 Engine Management – V6 – Diagnostics to
check for DTCs

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ISUZU KB P190 2007

Engine Mechanical – V6 Page 6A1–34
Page 6A1–34
2.4 Engine Misfire with Abnormal Internal
Lower Engine Noises
Cause Correction
Abnormalities, severe cracking, bumps or missing areas in
the accessory drive belt.
Abnormalities in the accessory drive system and/or
components may cause engine speed variations that result
in a misfire diagnostic trouble code (DTC). A misfire code
may be present without an ac tual misfire condition. Replace the accessory drive belt, refer to 3.5 Accessory
Drive Belt.
Refer to 6C1-2 Engine Management – V6 – Diagnostics to
check for DTCs
Worn, damaged or misaligned accessory drive components
and excessive pulley run-out may lead to a misfire DTC.
A misfire code may be present without an actual misfire
condition. Inspect the components and repair or replace as required.
Refer to 6C1-2 Engine Management – V6 – Diagnostics to
check for DTCs
Loose or Incorrectly fitted flexplate or crankshaft balancer
assembly.
A misfire code may be present without an actual misfire
condition. Repair or replace the flexplat
e or crankshaft balancer as
required, refer to 3.13 Crankshaft Balancer Assembly or
4.3 Flexplate Assembly.
Worn or broken piston rings.
Oil consumption may or may not cause an actual misfire. 1 Inspect the spark plugs for oil deposits, refer to 6C1-3
Engine Management – V6 – Service Operations.
2 Check the cylinders for a loss of compression, refer to 2.15 Engine Compression Test.
3 Perform compression testing to identify the cause of
low compression.
4 Repair or replace components as required.
Worn crankshaft thrust bearing.
Severely worn thrust surfaces on the crankshaft and/or
thrust bearing may permit fore and aft movement of the
crankshaft and create a DTC wi thout an actual misfire
condition being present. Replace the crankshaft and/or bear
ings as required, refer to
4.6 Crankshaft and Main Bearings.
Refer to 6C1-2 Engine Management – V6 – Diagnostics to
check for DTCs

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Engine Mechanical – V6 Page 6A1–37
Page 6A1–37
2.7 Engine Misfire with Excessive Oil
Consumption
Cause Correction
Worn valves, valve guides and/or valve stem oil seals. 1 Inspect the spark plugs for coolant saturation, refer to
6C1-3 Engine Management – V6 – Service
Operations.
2 Repair or replace components as required, refer to 3.22 Cylinder Head Assembly.
Worn or broken piston rings.
Oil consumption may or may not cause an actual misfire. 1 Inspect the spark plugs for oil deposits, refer to 6C1-3
Engine Management – V6 – Service Operations.
2 Check the cylinders for a loss of compression, refer to 2.15 Engine Compression Test.
3 Perform compression testing to identify the cause of
low compression.
4 Repair or replace components as required.

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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.

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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.

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