
DIAGNOSIS AND TESTINGÐCYLINDER
COMPRESSION PRESSURE
The results of a cylinder compression pressure test
can be utilized to diagnose several engine malfunc-
tions.
Ensure the battery is completely charged and the
engine starter motor is in good operating condition.
Otherwise, the indicated compression pressures may
not be valid for diagnosis purposes.
(1) Clean the spark plug recesses with compressed
air.
(2) Remove the spark plugs (Refer to 8 - ELEC-
TRICAL/IGNITION CONTROL/SPARK PLUG -
REMOVAL).
(3) Secure the throttle in the wide-open position.
(4) Disconnect the ignition coil.
(5) Insert a compression pressure gauge and rotate
the engine with the engine starter motor for three
revolutions.
(6) Record the compression pressure on the third
revolution. Continue the test for the remaining cylin-
ders.
(Refer to 9 - ENGINE - SPECIFICATIONS) for the
correct engine compression pressures.
DIAGNOSIS AND TESTINGÐCYLINDER
COMBUSTION PRESSURE LEAKAGE
The combustion pressure leakage test provides an
accurate means for determining engine condition.
Combustion pressure leakage testing will detect:
²Exhaust and intake valve leaks (improper seat-
ing)
²Leaks between adjacent cylinders or into water
jacket²Any causes for combustion/compression pressure
loss
WARNING: DO NOT REMOVE THE RADIATOR CAP
WITH THE SYSTEM HOT AND UNDER PRESSURE.
SERIOUS BURNS FROM HOT COOLANT CAN
OCCUR.
Check the coolant level and fill as required. DO
NOT install the radiator cap.
Start and operate the engine until it attains nor-
mal operating temperature, then turn OFF the
engine.
Remove the spark plugs.
Remove the oil filler cap.
Remove the air cleaner.
Calibrate the tester according to the manufactur-
er's instructions. The shop air source for testing
should maintain 483 kPa (70 psi) minimum, 1,379
kPa (200 psi) maximum and 552 kPa (80 psi) recom-
mended.
Perform the test procedure on each cylinder accord-
ing to the tester manufacturer's instructions. While
testing, listen for pressurized air escaping through
the throttle body, tailpipe or oil filler cap opening.
Check for bubbles in the radiator coolant.
All gauge pressure indications should be equal,
with no more than 25% leakage.
FOR EXAMPLE:At 552 kPa (80 psi) input pres-
sure, a minimum of 414 kPa (60 psi) should be main-
tained in the cylinder.
Refer to CYLINDER COMBUSTION PRESSURE
LEAKAGE DIAGNOSIS CHART below
CYLINDER COMBUSTION PRESSURE LEAKAGE DIAGNOSIS CHART
CONDITION POSSIBLE CAUSE CORRECTION
AIR ESCAPES THROUGH
THROTTLE BODYIntake valve bent, burnt, or not
seated properlyInspect valve and valve seat.
Reface or replace, as necessary
AIR ESCAPES THROUGH
TAILPIPEExhaust valve bent, burnt, or not
seated properlyInspect valve and valve seat.
Reface or replace, as necessary
AIR ESCAPES THROUGH
RADIATORHead gasket leaking or cracked
cylinder head or blockRemove cylinder head and inspect.
Replace defective part
MORE THAN 50% LEAKAGE
FROM ADJACENT CYLINDERSHead gasket leaking or crack in
cylinder head or block between
adjacent cylindersRemove cylinder head and inspect.
Replace gasket, head, or block as
necessary
MORE THAN 25% LEAKAGE AND
AIR ESCAPES THROUGH OIL
FILLER CAP OPENING ONLYStuck or broken piston rings;
cracked piston; worn rings and/or
cylinder wallInspect for broken rings or piston.
Measure ring gap and cylinder
diameter, taper and out-of-round.
Replace defective part as necessary
9 - 124 ENGINE 5.9LBR/BE
ENGINE 5.9L (Continued)

DESCRIPTION SPECIFICATION
Bearing Clearance
Journal #1 0.013 ± 0.038 mm
(0.0005 ± 0.0015 in.)
Journals#2-50.013 ± 0.051 mm
(0.0005 ± 0.002 in.)
Service Limit
Journal #1 0.0381 mm (0.0015 in.)
Journals #2-5 0.064 mm (0.0025 in.)
Crankshaft End Play 0.051 ± 0.178 mm
(0.002 ± 0.007 in.)
Service Limit 0.254 mm (0.010 in.)
CYLINDER BLOCK
Cylinder Bore
Diameter 101.60 ± 101.65 mm
(4.000 ± 4.002 in.)
Out of Round (Max.) 0.0254 mm (0.001 in.)
Taper (Max.) 0.0254 mm (0.001 in.)
Lifter Bore
Diameter 22.99 ± 23.01 mm
(0.9051 ± 0.9059 in.)
Distributor Drive Bushing
Press Fit
Bushing to Bore
Interference0.0127 ± 0.3556 mm
(0.0005 ± 0.0140 in.)
Shaft to Bushing
Clearance0.0178 ± 0.0686 mm
(0.0007 ± 0.0027 in.)
CYLINDER HEAD AND VALVES
Valve Seat
Angle 44.25É ± 44.75É
Runout (Max.) 0.0762 mm (0.003 in.)
Width (Finish)
Intake 1.016 ± 1.524 mm
(0.040 ± 0.060 in.)
Exhaust 1.524 ± 2.032 mm
(0.060 ± 0.080 in.)DESCRIPTION SPECIFICATION
Valves
Face Angle 43.25É ± 43.75É
Head Diameter
Intake 47.752 mm (1.88 in.)
Exhaust 41.072 (1.617 in.)
Length (Overall)
Intake 126.21 ± 126.85 mm
(4.969 ± 4.994 in.)
Exhaust 126.44 ± 127.30 mm
(4.978 ± 5.012 in.)
Lift (@ zero lash)
Intake 10.414 mm (0.410 in.)
Exhaust 10.592 mm (0.417 in.)
Stem Diameter
Intake 9.449 ± 9.474 mm
(0.372 ± 0.373 in.)
Exhaust 9.423 ± 9.449 mm
(0.371 ± 0.372 in.)
Guide Bore 9.500 ± 9.525 mm
(0.374 ± 0.375 on.)
Stem to Guide Clearance
Intake 0.0254 ± 0.0762 mm
(0.001 ± 0..003 in.)
Exhaust 0.0508 ± 0.1016 mm
(0.002 ± 0.004 in.)
Service Limit 0.4318 (0.017 in.)
Valve Springs
Free Length 49.962 mm (1.967 in.)
Spring Tension
Valve closed 378 N @ 41.66 mm
(85 lbs. @ 1.64 in.)
Valve open 890 N @ 30.89 mm
(200 lbs. @ 1.212 in.)
Number of Coils 6.8
Installed Height 41.66 mm (1.64 in.)
Wire Diameter 4.50 mm (0.177 in.)
9 - 130 ENGINE 5.9LBR/BE
ENGINE 5.9L (Continued)

DESCRIPTION SPECIFICATION
HYDRAULIC TAPPETS
Body Diameter 22.949 ± 22.962 mm
(0.9035 ± 0.9040 in.)
Clearance (to bore) 0.0279 ± 0.0610 mm
(0.0011 ± 0.0024 in.)
Dry Lash 1.524 ± 5.334 mm
(0.060 ± 0.210 in.)
Push Rod Length 175.64 ± 176.15 mm
(6.915 ± 6.935 in.)
OIL PRESSURE
Curb Idle (Min.*) 41.4 kPa (6 psi)
@ 3000 rpm 207 ± 552 kPa (30 ± 80
psi)
Oil Pressure Bypass
Valve Setting 62 ± 103 kPa (9 ± 15 psi)
Switch Actuating
Pressure34.5 ± 48.3 kPa (5 ± 7
psi)
* If oil pressure is zero at curb idle, DO NOT RUN
ENGINE.
OIL PUMP
Clearance over Rotors
(Max.)0.1016 mm (0.004 in.)
Cover Out of Flat (Max.) 0.0381 mm (0.0015 in.)
Inner Rotor Thickness
(Min.)20.955 mm (0.825 in.)
Outer Rotor
Clearance (Max.) 0.3556 mm (0.014 in.)
Diameter (Min.) 62.7126 mm (2.469 in.)
Thickness (Min.) 20.955 mm (0.825 in.)
Tip Clearance between
Rotors (Max.) 0.2032 mm (0.008 in.)
PISTONS
Clearance at Top of Skirt 0.013 ± 0.038 mm
(0.0005 ± 0.0015 in.)
Land Clearance (Diam.) 0.508 ± 0.660 mm
(0.020 ± 0.026 in.)DESCRIPTION SPECIFICATION
Piston Length 81.03 mm (3.19 in.)
Piston Ring Groove
Depth
Groove #1&2 4.761 ± 4.912 mm
(0.187 ± 0.193 in.)
Groove #3 3.996 ± 4.177 mm
(0.157 ± 0.164 in.)
Weight 582 ± 586 grams
(20.53 ± 20.67 oz.)
PISTON PINS
Clearance in Piston 0.006 ± 0.019 mm
(0.00023 ± 0.00074 in.)
Diameter 25.007 ± 25.015 mm
(0.9845 ± 0.9848 in.)
End Play NONE
Length 67.8 ± 68.3 mm
(2.67 ± 2.69 in.)
PISTON RINGS
Ring Gap
Compression Ring (Top) 0.30 ± 0.55 mm
(0.012 ± 0.022 in.)
Compression Ring (2nd) 0.55 ± 0.80 mm
(0.022 ± 0.031 in.)
Oil Control (Steel Rails) 0.381 ± 1.397 mm
(0.015 ± 0.055 in.)
Ring Side Clearance
Compression Rings 0.040 ± 0.085 mm
(0.0016 ± 0.0033 in.)
Oil Ring (Steel Rails) 0.05 ± 0.21 mm
(0.002 ± 0.008 in.)
Ring Width
Compression rings 1.530 ± 1.555 mm
(0.060 ± 0.061 in.)
Oil Ring (Steel Rails) ±
Max.0.447 ±0.473 mm
(0.018 ± 0.019 in.)
BR/BEENGINE 5.9L 9 - 131
ENGINE 5.9L (Continued)

DESCRIPTION SPECIFICATION
VALVE TIMING
Exhaust Valve
Closes (ATDC) 33É
Opens (BBDC) 56É
Duration 269É
Intake Valve
Closes (ATDC) 62É
Opens (BBDC) 7É
Duration 249É
Valve Overlap 41ÉOVERSIZE AND UNDERSIZE ENGINE
COMPONENT MARKINGS CHART
OS-US Item Identification Location of
Identification
U/S Crankshaft R or M M-2-3
ect.Milled flat on
.025 MM (indicating No.
2&No. three
(.001
IN.)3 main bearing crankshaft
journal) and/or counterweight.
R-1-4 ect.
(indicating No.
1&
4 connecting
rod
journal)
O/S Cylinder A Following
.508 mm Bores engine serial
(.020 in.) number.
O/S TappetsL3/89
.203 mm diamound
(.008 in.) -shaped
stamp Top
pad
Ð Front of
engine and
flat
ground on
outside
surface
of each O/S
tappet bore.
O/S Valve
StemsX Milled pad
.127 mm adjacent to
two
(0.005
in.)3/89tapped
holes on
each
end of
cylinder
head.
9 - 132 ENGINE 5.9LBR/BE
ENGINE 5.9L (Continued)

SPECIAL TOOLS
5.9L ENGINE
Oil Pressure Gauge C-3292
Engine Support Fixture C-3487±A
Valve Spring Compressor MD-998772±A
Adaptor 6633
Adaptor 6716A
Valve Guide Sleeve C-3973
Dial Indicator C-3339
Puller C-3688
Puller 1026
Crankshaft Damper Removal Insert 8513
9 - 134 ENGINE 5.9LBR/BE
ENGINE 5.9L (Continued)

CYLINDER HEAD
DESCRIPTIONÐCYLINDER HEAD
The cast iron cylinder heads (Fig. 4) are mounted
to the cylinder block using ten bolts. The spark plugs
are located in the peak of the wedge between the
valves.
DESCRIPTIONÐCYLINDER HEAD COVER
GASKET
The cylinder head cover gasket (Fig. 5) is a steel-
backed silicone gasket, designed for long life usage.
OPERATIONÐCYLINDER HEAD
The cylinder head closes the combustion chamber
allowing the pistons to compress the air fuel mixture to
the correct ratio for ignition. The valves located in the
cylinder head open and close to either allow clean airinto the combustion chamber or to allow the exhaust
gases out, depending on the stroke of the engine.
OPERATION
The steel-backed silicone gasket is designed to seal
the cylinder head cover for long periods of time
through extensive heat and cold, without failure. The
gasket is designed to be reusable.
DIAGNOSIS AND TESTINGÐCYLINDER HEAD
GASKET FAILURE
A cylinder head gasket leak can be located between
adjacent cylinders or between a cylinder and the
adjacent water jacket.
²Possible indications of the cylinder head gasket
leaking between adjacent cylinders are:
²Loss of engine power
²Engine misfiring
²Poor fuel economy
²Possible indications of the cylinder head gasket
leaking between a cylinder and an adjacent water
jacket are:
²Engine overheating
²Loss of coolant
²Excessive steam (white smoke) emitting from
exhaust
²Coolant foaming
CYLINDER-TO-CYLINDER LEAKAGE TEST
To determine if an engine cylinder head gasket is
leaking between adjacent cylinders, follow the proce-
dures in Cylinder Compression Pressure Test in this
section. An engine cylinder head gasket leaking
between adjacent cylinders will result in approxi-
mately a 50±70% reduction in compression pressure.
CYLINDER-TO-WATER JACKET LEAKAGE TEST
WARNING: USE EXTREME CAUTION WHEN THE
ENGINE IS OPERATING WITH COOLANT PRES-
SURE CAP REMOVED.
VISUAL TEST METHOD
With the engine cool, remove the coolant pressure
cap. Start the engine and allow it to warm up until
thermostat opens.
If a large combustion/compression pressure leak
exists, bubbles will be visible in the coolant.
COOLING SYSTEM TESTER METHOD
WARNING: WITH COOLING SYSTEM TESTER IN
PLACE, PRESSURE WILL BUILD UP FAST. EXCES-
SIVE PRESSURE BUILT UP, BY CONTINUOUS
ENGINE OPERATION, MUST BE RELEASED TO A
SAFE PRESSURE POINT. NEVER PERMIT PRES-
SURE TO EXCEED 138 kPa (20 psi).
Fig. 4 Cylinder Head AssemblyÐV-8 Gas Engines
1 - EXHAUST VALVE
2 - SPARK PLUGS
3 - EXHAUST VALVES
4 - SPARK PLUGS
5 - EXHAUST VALVE
6 - INTAKE VALVES
7 - INTAKE VALVES
Fig. 5 Cylinder Head Cover Gasket V-8 Gas Engines
1 - CYLINDER HEAD COVER GASKET
9 - 136 ENGINE 5.9LBR/BE

Install Cooling System Tester 7700 or equivalent to
pressure cap neck. Start the engine and observe the
tester's pressure gauge. If gauge pulsates with every
power stroke of a cylinder a combustion pressure
leak is evident.
CHEMICAL TEST METHOD
Combustion leaks into the cooling system can also
be checked by using Bloc-Chek Kit C-3685-A or
equivalent. Perform test following the procedures
supplied with the tool kit.
REMOVAL
(1) Disconnect the battery negative cable.
(2) Drain cooling system (Refer to 7 - COOLING -
STANDARD PROCEDURE).
(3)
Remove the air cleaner resonator and duct work.
(4) Remove the intake manifold-to-generator
bracket support rod. Remove the generator.
(5) Remove closed crankcase ventilation system.
(6) Disconnect the evaporation control system.
(7) Perform the Fuel System Pressure Release pro-
cedure (Refer to 14 - FUEL SYSTEM/FUEL DELIV-
ERY - STANDARD PROCEDURE). Disconnect the
fuel supply line (Refer to 14 - FUEL SYSTEM/FUEL
DELIVERY/QUICK CONNECT FITTING - STAN-
DARD PROCEDURE).
(8) Disconnect accelerator linkage and if so
equipped, the speed control and transmission kick-
down cables.
(9) Remove distributor cap and wires.
(10) Disconnect the coil wires.
(11) Disconnect heat indicator sending unit wire.
(12) Disconnect heater hoses and bypass hose.
(13) Remove cylinder head covers and gaskets
(Refer to 9 - ENGINE/CYLINDER HEAD/CYLIN-
DER HEAD COVER(S) - REMOVAL).
(14)
Remove intake manifold (Refer to 9 - ENGINE/
MANIFOLDS/INTAKE MANIFOLD - REMOVAL) and
throttle body as an assembly. Discard the flange side
gaskets and the front and rear cross-over gaskets.
(15) Remove exhaust manifolds (Refer to 9 -
ENGINE/MANIFOLDS/EXHAUST MANIFOLD -
REMOVAL).
(16) Remove rocker arm assemblies and push rods.
Identify to ensure installation in original locations.
(17) Remove the head bolts from each cylinder
head and remove cylinder heads. Discard the cylin-
der head gasket.
(18) Remove spark plugs.
CLEANING
Clean all surfaces of cylinder block and cylinder
heads.
Clean cylinder block front and rear gasket surfaces
using a suitable solvent.
INSPECTION
Inspect all surfaces with a straightedge if there is
any reason to suspect leakage. If out-of-flatness
exceeds 0.00075mm/mm (0.0001in./in.) times the
span length in any direction, either replace head or
lightly machine the head surface.
FOR EXAMPLE:ÐA 305 mm (12 in.) span is
0.102 mm (0.004 in.) out-of-flat. The allowable out-of-
flat is 305 x 0.00075 (12 x 0.00075) equals 0.23 mm
(0.009 in.). This amount of out-of-flat is acceptable.
The cylinder head surface finish should be
1.78-3.00 microns (70-125 microinches).
Inspect push rods. Replace worn or bent rods.
INSTALLATION
(1) Clean all surfaces of cylinder block and cylin-
der heads.
(2) Clean cylinder block front and rear gasket sur-
faces using a suitable solvent.
(3) Position new cylinder head gaskets onto the
cylinder block.
(4) Position cylinder heads onto head gaskets and
cylinder block.
(5) Starting at top center, tighten all cylinder head
bolts, in sequence (Fig. 6).
CAUTION: When tightening the rocker arm bolts,
make sure the piston in that cylinder is NOT at
TDC. Contact between the valves and piston could
occur.
(6) Install push rods and rocker arm assemblies in
their original position. Tighten the bolts to 28 N´m
(21 ft. lbs.) torque.
(7) Install the intake manifold (Refer to 9 -
ENGINE/MANIFOLDS/INTAKE MANIFOLD -
INSTALLATION) and throttle body assembly.
(8) Install exhaust manifolds (Refer to 9 -
ENGINE/MANIFOLDS/EXHAUST MANIFOLD -
INSTALLATION).
Fig. 6 Cylinder Head Bolt Tightening Sequence
BR/BEENGINE 5.9L 9 - 137
CYLINDER HEAD (Continued)

(9) If required, adjust spark plugs to specifications.
Install the plugs and tighten to 41 N´m (30 ft. lbs.)
torque.
(10) Install coil wire.
(11) Connect heat indicator sending unit wire.
(12) Connect the heater hoses and bypass hose.
(13) Install distributor cap and wires.
(14) Connect the accelerator linkage and if so
equipped, the speed control and transmission kick-
down cables.
(15) Install the fuel supply line (Refer to 14 -
FUEL SYSTEM/FUEL DELIVERY/QUICK CON-
NECT FITTING - STANDARD PROCEDURE).
(16) Install the generator and drive belt (Refer to 7
- COOLING/ACCESSORY DRIVE/DRIVE BELTS -
INSTALLATION). Tighten generator mounting bolt
to 41 N´m (30 ft. lbs.) torque. Tighten the adjusting
strap bolt to 23 N´m (200 in. lbs.) torque.
(17) Install the intake manifold-to-generator
bracket support rod. Tighten the bolts.
(18) Place the cylinder head cover gaskets in posi-
tion and install cylinder head covers (Refer to 9 -
ENGINE/CYLINDER HEAD/CYLINDER HEAD
COVER(S) - INSTALLATION).
(19) Install closed crankcase ventilation system.
(20) Connect the evaporation control system.
(21) Install the air cleaner.
(22) Fill cooling system (Refer to 7 - COOLING -
STANDARD PROCEDURE).
(23) Connect the negative cable to the battery.
(24) Start engine check for leaks.
CYLINDER HEAD COVER(S)
REMOVAL
NOTE: A steel backed silicon gasket is used with
the cylinder head cover (Fig. 7). This gasket can be
used again.
(1) Disconnect the negative cable from the battery.(2) Disconnect the spark plug wires form the spark
plugs and set aside.
(3) Disconnect closed ventilation system and evap-
oration control system from cylinder head cover.
(4) Remove cylinder head cover and gasket.
CLEANING
Clean cylinder head cover gasket surface.
Clean head rail, if necessary.
INSPECTION
Inspect cover for distortion and straighten, if nec-
essary.
Check the gasket for use in head cover installation.
If damaged, use a new gasket.
INSTALLATION
(1) The cylinder head cover gasket can be used
again. Install the gasket onto the head rail.
(2) Position the cylinder head cover onto the gas-
ket. Tighten the bolts to 11 N´m (95 in. lbs.) torque.
(3) Install closed crankcase ventilation system and
evaporation control system.
(4)
Connect the spark plug wires to the spark plugs.
(5) Connect the negative cable to the battery.
INTAKE/EXHAUST VALVES &
SEATS
DESCRIPTION
Both the intake and exhaust valves are made of
steel. The intake valve is 48.768 mm (1.92 inches) in
diameter and the exhaust valve is 41.148 mm (1.62
inches) in diameter and has a 2.032 mm (0.080 inch)
wafer interia welded to the tip for durability. These
valves are not splayed.
STANDARD PROCEDUREÐVALVES, GUIDES
AND SPRINGS
VALVE CLEANING
Clean valves thoroughly. Discard burned, warped,
or cracked valves.
Remove carbon and varnish deposits from inside of
valve guides with a reliable guide cleaner.
VALVE GUIDES
Measure valve stems for wear. If wear exceeds
0.051 mm (0.002 in.), replace the valve.
Measure valve stem guide clearance as follows:
(1) Install Valve Guide Sleeve Tool C-3973 over
valve stem and install valve (Fig. 8). The special
sleeve places the valve at the correct height for
checking with a dial indicator.
Fig. 7 Cylinder Head Cover Gasket
1 - CYLINDER HEAD COVER GASKET
9 - 138 ENGINE 5.9LBR/BE
CYLINDER HEAD (Continued)