Downloaded from www.Manualslib.com manuals search engine (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) Install the air inlet hose.
(5) Connect the negative cable to the battery.
ROCKER ARMS AND PUSH RODS
REMOVAL
(1) Remove cylinder head cover and gasket. Refer
to Cylinder Head Cover in this section for correct
procedure.
(2) Remove the rocker arm bolts and pivots (Fig.
44). Place them on a bench in the same order as
removed.
(3) Remove the push rods and place them on a
bench in the same order as removed.
INSTALLATION
(1) Rotate the crankshaft until the ªV8º mark lines
up with the TDC mark on the timing chain case
cover. This mark is located 147É ATDC from the No.1
firing position.
(2) Install the push rods in the same order as
removed.
(3) Install rocker arm and pivot assemblies in the
same order as removed. Tighten the rocker arm bolts
to 28 N´m (21 ft. lbs.) torque.
CAUTION: DO NOT rotate or crank the engine dur-
ing or immediately after rocker arm installation.
Allow the hydraulic roller tappets adequate time to
bleed down (about 5 minutes).
(4) Install cylinder head cover.
VALVE SPRING AND STEM SEAL
REPLACEMENT-IN VEHICLE
(1) Remove the air cleaner.
(2) Remove cylinder head covers and spark plugs.(3) Remove coil wire from distributor and secure to
good ground to prevent engine from starting.
(4) Using suitable socket and flex handle at crank-
shaft retaining bolt, turn engine so the No.1 piston is
at TDC on the compression stroke.
(5) Remove rocker arms.
(6) With air hose attached to an adapter installed
in No.1 spark plug hole, apply 620-689 kPa (90-100
psi) air pressure.
(7) Using Valve Spring Compressor Tool
MD-998772A with adaptor 6716A, compress valve
spring and remove retainer valve locks and valve
spring.
(8) Install seals on the exhaust valve stem and
position down against valve guides.
(9) The intake valve stem seals should be pushed
firmly and squarely over the valve guide using the
valve stem as a guide. DO NOT force seal against top
of guide. When installing the valve retainer locks,
compress the spring only enough to install the locks.
(10) Follow the same procedure on the remaining 7
cylinders using the firing sequence 1-8-4-3-6-5-7-2.
Make sure piston in cylinder is at TDC on the valve
spring that is being removed.
(11) Remove adapter from the No.1 spark plug
hole and install spark plugs.
(12) Install rocker arms.
(13) Install covers and coil wire to distributor.
(14) Install air cleaner.
(15) Road test vehicle.
CYLINDER HEAD
REMOVAL
(1) Disconnect the battery negative cable.
(2) Drain cooling system Refer to COOLING SYS-
TEM.
(3) Remove the intake manifold-to-generator
bracket support rod. Remove the generator.
(4) Remove closed crankcase ventilation system.
(5) Disconnect the evaporation control system.
(6) Remove the air cleaner assembly and air inlet
hose.
(7) Perform fuel system pressure release proce-
dure. Refer to FUEL SYSTEM.
(8) Disconnect the fuel supply line.
(9) Disconnect accelerator linkage and if so
equipped, the speed control and transmission kick-
down cables.
(10) Remove distributor cap and wires.
(11) Disconnect the coil wires.
(12) Disconnect heat indicator sending unit wire.
(13) Disconnect heater hoses and bypass hose.
(14) Remove cylinder head covers and gaskets.
Fig. 44 Rocker Arms
1 ± ROCKER ARMS
2 ± CYLINDER HEAD
DN5.2L ENGINE 9 - 107
REMOVAL AND INSTALLATION (Continued)
Downloaded from www.Manualslib.com manuals search engine (15) Remove intake manifold and throttle body as
an assembly. Discard the flange side gaskets and the
front and rear cross-over gaskets.
(16) Remove exhaust manifolds.
(17) Remove rocker arm assemblies and push rods.
Identify to ensure installation in original locations.
(18) Remove the head bolts from each cylinder
head and remove cylinder heads. Discard the cylin-
der head gasket.
(19) Remove spark plugs.
INSTALLATION
(1) Position the new cylinder head gaskets onto
the cylinder block.
(2) Position the cylinder heads onto head gaskets
and cylinder block.
(3) Starting at top center, tighten all cylinder head
bolts, in sequence, to 68 N´m (50 ft. lbs.) torque (Fig.
45). Repeat procedure, tighten all cylinder head bolts
to 143 N´m (105 ft. lbs.) torque. Repeat procedure to
confirm that all bolts are at 143 N´m (105 ft. lbs.)
torque.
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.
(4) Install push rods and rocker arm assemblies in
their original position. Tighten the bolts to 28 N´m
(21 ft. lbs.) torque.
(5) Install the intake manifold and throttle body
assembly.
(6) Install exhaust manifolds. Tighten the bolts
and nuts to 34 N´m (25 ft. lbs.) torque.
(7) Adjust spark plugs to specifications. Refer to
IGNITION SYSTEM. Install the plugs and tighten to
41 N´m (30 ft. lbs.) torque.
(8) Install coil wires.
(9) Connect heat indicator sending unit wire.(10) Connect the heater hoses and bypass hose.
(11) Install distributor cap and wires.
(12) Connect the accelerator linkage and if so
equipped, the speed control and transmission kick-
down cables.
(13) Install the fuel supply line.
(14) Install the generator and drive belt. Tighten
generator mounting bolt to 41 N´m (30 ft. lbs.)
torque.
(15) Install the intake manifold-to-generator
bracket support rod. Tighten the bolts.
(16) Place the cylinder head cover gaskets in posi-
tion and install cylinder head covers. Tighten the
bolts to 11 N´m (95 in. lbs.) torque.
(17) Install closed crankcase ventilation system.
(18) Connect the evaporation control system.
(19) Install the air cleaner assembly and air inlet
hose.
(20) Install the heat shields. Tighten the bolts to
41 N´m (30 ft. lbs.) torque.
(21) Fill cooling system.
(22) Connect the battery negative cable.
VALVES AND VALVE SPRINGS
REMOVAL
(1) Remove the cylinder head. Refer to Cylinder
Head in this section for correct procedure.
(2) Compress valve springs using Valve Spring
Compressor Tool MD- 998772A and adapter 6716A.
(3) Remove valve retaining locks, valve spring
retainers, valve stem seals and valve springs.
(4) Before removing valves, remove any burrs from
valve stem lock grooves to prevent damage to the
valve guides. Identify valves to ensure installation in
original location.
INSTALLATION
(1) Clean valves thoroughly. Discard burned,
warped and cracked valves.
(2) Remove carbon and varnish deposits from
inside of valve guides with a reliable guide cleaner.
(3) Measure valve stems for wear. If wear exceeds
0.051 mm (0.002 inch), replace the valve.
(4) Coat valve stems with lubrication oil and insert
them in cylinder head.
(5) If valves or seats are reground, check valve
stem height. If valve is too long, replace cylinder
head.
(6) Install new seals on all valve guides. Install
valve springs and valve retainers.
(7) Compress valve springs with Valve Spring
Compressor Tool MD-998772A and adapter 6716A,
install locks and release tool. If valves and/or seats
are ground, measure the installed height of springs.
Make sure the measurement is taken from bottom ofFig. 45 Cylinder Head Bolt Tightening Sequence
9 - 108 5.2L ENGINEDN
REMOVAL AND INSTALLATION (Continued)
Downloaded from www.Manualslib.com manuals search engine TORQUE SPECIFICATIONS
TORQUE CHART 5.2L ENGINE
DESCRIPTION N´m Ft. In.
Lbs. Lbs.
Camshaft SprocketÐBolt 68 50 Ð
Camshaft Thrust PlateÐBolts 24 Ð 210
Chain Case CoverÐBolts 41 30 Ð
Connecting Rod CapÐBolts 61 45 Ð
Main Bearing CapÐBolts 115 85 Ð
Crankshaft PulleyÐBolts 24 Ð 210
Cylinder HeadÐBolts
Step 1 68 50 Ð
Step 2 143 105 Ð
Cylinder Head CoverÐBolts 11 Ð 95
Engine Support Bracket to
BlockÐ41 30 Ð
Bolts (4WD)
Exhaust Manifold to Cylinder
HeadÐ34 25 Ð
Bolts/Nuts
FlywheelÐBolts 75 55 Ð
Front InsulatorÐThrough
bolt/nut95 70 Ð
Front Insulator to Support
BracketÐ
Stud Nut (4WD) 41 30 Ð
Through Bolt/Nut 102 75 Ð
Front Insulator to BlockÐ 95 70 Ð
Bolts (2WD)
GeneratorÐMounting Bolts 41 30 Ð
Intake ManifoldÐBolts Refer to Procedure
Oil PanÐBolts 24 Ð 215
Oil PanÐDrain Plug 34 25 Ð
Oil PumpÐMounting Bolts 41 30 Ð
Oil Pump CoverÐBolts 11 Ð 95
Rear Insulator to BracketÐ
Through68 50 Ð
Bolt (2WD)
Rear Insulator to
Crossmember41 30 Ð
Support BracketÐNut (2WD)
Rear Insulator to
CrossmemberÐ68 50 Ð
Nuts (4WD)
DESCRIPTION N´m Ft. In.
Lbs. Lbs.
Rear Insulator to
TransmissionÐ68 50 Ð
Bolts (4WD)
Rear Insulator BracketÐBolts 68 50 Ð
(4WD Automatic)
Rear Support Plate to
Transfer Case41 30 Ð
ÐBolts
Rocker ArmÐBolts 28 21 Ð
Spark Plugs 41 30 Ð
Starter MotorÐMounting
Bolts68 50 Ð
Thermostat HousingÐBolts 25 Ð 225
Throttle BodyÐBolts 23 Ð 200
Torque Converter Drive
PlateÐBolts31 Ð 270
Transfer Case to Insulator
Mounting204 150 Ð
PlateÐNuts
Transmission Support
BracketÐ68 50 Ð
Bolts (2WD)
Vibration DamperÐBolt 183 135 Ð
Water Pump to Timing Chain
Case41 30 Ð
CoverÐBolts
SPECIAL TOOLS
5.2L ENGINE
Oil Pressure Gauge C-3292
9 - 132 5.2L ENGINEDN
SPECIFICATIONS (Continued)
Downloaded from www.Manualslib.com manuals search engine CYLINDER HEAD COVER GASKET
DESCRIPTION
The cylinder head cover gasket is a steel-backed
silicone gasket, designed for long life usage (Fig. 7).
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.
CYLINDER HEAD
DESCRIPTION
The cast iron cylinder heads (Fig. 8) are mounted
to the cylinder block using ten bolts. The spark plugs
are located in the peak of the wedge between the
valves.
OPERATION
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
air into the combustion chamber or to allow the
exhaust gases out, depending on the stroke of the
engine.
VALVES AND VALVE SPRINGS
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.
ENGINE OIL PAN
DESCRIPTION
The stamped steel engine oil pan is located at the
bottom of the engine, and contains a drain plug for
draining the engine oil.
OPERATION
The oil pan holds the engine oil and seals and pro-
tects the engine lower components from contami-
nates.
CRANKSHAFT OIL SEALS
DESCRIPTION
The crankshaft rear seal is a two piece viton seal.
The crankshaft front seal is a one piece viton seal
with a steel housing. The front seal is located in the
engine front cover. One part of the two piece rear
seal is located in a slot in the number five (5) crank-
shaft main bore, the second part of the two piece seal
is located in the number five (5) main bearing cap.
OPERATION
The crankshaft seals prevent oil from leaking from
around the crankshaft, either from the rear of the
engine or from the engine front cover.
PISTON AND CONNECTING ROD
DESCRIPTION
The pistons are made of aluminum and have three
ring grooves, the top two grooves are for the compres-
sion rings and the bottom groove is for the oil control
ring. The connecting rods are forged steel and are
coined prior to heat treat. The piston pins are press
fit.
Fig. 7 Cylinder Head Cover Gasket V-8 Gas Engines
1 ± CYLINDER HEAD COVER GASKET
Fig. 8 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
9 - 140 5.9L ENGINEDN
DESCRIPTION AND OPERATION (Continued)
Downloaded from www.Manualslib.com manuals search engine SERVICE DIAGNOSISÐGASOLINE ENGINES
PERFORMANCE DIAGNOSIS CHARTÐGASOLINE ENGINES
CONDITION POSSIBLE CAUSES CORRECTION
ENGINE WILL
NOT CRANK1. Weak or dead battery 1. Charge/Replace Battery. Refer to Group 8A,
Battery, for correct procedures. Check charging
system. Refer to Group 8C, Charging Systems, for
correct procedures.
2. Corroded or loose battery
connections2. Clean/tighten suspect battery/starter connections
3. Faulty starter or related circuit(s) 3. Check starting system. Refer to Group 8B,
Starting Systems, for correct diagnostics/procedures
4. Seized accessory drive
component4. Remove accessory drive belt and attempt to start
engine. If engine starts, repair/replace seized
component.
5. Engine internal mechanical
failure or hydro-static lock5. Refer to Group 9, Engine, for correct diagnostics/
procedures
ENGINE CRANKS
BUT WILL NOT
START1. No spark 1. Check for spark. Refer to Group 8D, Ignition
System, for correct procedures.
2. No fuel 2. Perform fuel pressure test, and if necessary,
inspect fuel injector(s) and driver circuits. Refer to
Group 14, Fuel System, for correct procedures.
3. Low or no engine compression 3. Perform cylinder compression pressure test. Refer
to Group 9, Engine, for correct procedures.
ENGINE LOSS OF
POWER1. Worn or burned distributor rotor 1. Install new distributor rotor
2. Worn distributor shaft 2. Remove and repair distributor (Refer to Group 8D,
Ignition System
3. Worn or incorrect gapped spark
plugs3. Clean plugs and set gap. (Refer to Group 8D,
Ignition System)
4. Dirt or water in fuel system 4. Clean system and replace fuel filter
5. Faulty fuel pump 5. Install new fuel pump
6. Incorrect valve timing 6. Correct valve timing
7. Blown cylinder head gasket 7. Install new cylinder head gasket
8. Low compression 8. Test cylinder compression
9. Burned, warped, or pitted valves 9. Install/Reface valves as necessary
10. Plugged or restricted exhaust
system10. Install new parts as necessary
11. Faulty ignition cables 11. Replace any cracked or shorted cables
12. Faulty ignition coil 12. Test and replace, as necessary (Refer to Group
8D, Ignition System)
ENGINE STALLS
OR ROUGH IDLE1. Carbon build-up on throttle plate 1. Remove throttle body and de-carbon. (Refer to
Group 14 for correct procedures)
2. Engine idle speed too low 2. Check Idle Air Control circuit. (Refer to Group 14,
Fuel System)
9 - 142 5.9L ENGINEDN
DIAGNOSIS AND TESTING (Continued)
Downloaded from www.Manualslib.com manuals search engine CONDITION POSSIBLE CAUSES CORRECTION
3. Worn or incorrectly gapped spark
plugs3. Replace or clean and re-gap spark plugs (Refer to
group 8D, Ignition System)
4. Worn or burned distributor rotor 4. Install new distributor rotor
5. Spark plug cables defective or
crossed5. Check for correct firing order or replace spark plug
cables. (Refer to Group 8D, Ignition System for
correct procedures.)
6. Faulty coil 6. Test and replace, if necessary (Refer to group 8D,
Ignition System)
7. Intake manifold vacuum leak 7. Inspect intake manifold gasket and vacuum hoses.
Replace if necessary
8. EGR valve leaking or stuck open 8. Test and replace, if necessary (Refer to group 25,
Emission Control Systems)
ENGINE MISSES
ON
ACCELERATION1. Worn or incorrectly gapped spark
plugs1. Replace spark plugs or clean and set gap. (Refer
to group 8D, Ignition System)
2. Spark plug cables defective or
crossed2. Replace or rewire secondary ignition cables. Refer
to Group 8D, Ignition System
3. Dirt in fuel system 3. Clean fuel system
4. Burned, warped or pitted valves 4. Install new valves
5. Faulty coil 5. Test and replace as necessary (refer to group 8D,
Ignition System)
MECHANICAL DIAGNOSIS CHARTÐGASOLINE ENGINES
CONDITION POSSIBLE CAUSES CORRECTION
NOISY VALVES/
LIFTERS1. High or low oil level
in crankcase1. Check for correct oil level. Adjust oil level by draining or adding
as needed
2. Thin or diluted oil 2. Change oil (Refer to Engine Oil Service in this group)
3. Low oil pressure 3. Check engine oil level. If ok, Perform oil pressure test. Refer to
this group for engine oil pressure test/specifications
4. Dirt in tappets/lash
adjusters4. Clean/replace hydraulic tappets/lash adjusters
5. Bent push rod(s) 5. Install new push rods
6. Worn rocker arms 6. Inspect oil supply to rocker arms and replace worn arms as
needed
7. Worn tappets/lash
adjusters7. Install new hydraulic tappets/lash adjusters
8. Worn valve guides 8. Inspect all valve guides and replace as necessary
9. Excessive runout of
valve seats or valve
faces9. Grind valves and seats
DN5.9L ENGINE 9 - 143
DIAGNOSIS AND TESTING (Continued)
Downloaded from www.Manualslib.com manuals search engine CONDITION POSSIBLE CAUSES CORRECTION
OIL LEAKS 1. Misaligned or
deteriorated gaskets1. Replace gasket
2. Loose fastener,
broken or porous metal
part2. Tighten, repair or replace the part
3. Front or rear
crankshaft oil seal
leaking3. Replace seal
4. Leaking oil gallery
plug or cup plug4. Remove and reseal threaded plug. Replace cup style plug
5. Leaking intake 5. Replace gaskets
manifold cross-over
gaskets
EXCESSIVE OIL
CONSUMPTION
OR SPARK
PLUGS OIL
FOULED1. PCV System
malfunction1. Refer to group 25, Emission Control System for correct
operation
2. Intake manifold 2. Replace plenum
plenum pan gasket pan gasket
failure
3. Defective valve 3. Replace seals
stem seal(s)
4. Worn or broken
piston rings4. Hone cylinder bores. Install new rings
5. Scuffed pistons/
cylinder walls5. Hone cylinder bores and replace pistons as required
6. Carbon in oil control
ring groove6. Remove rings and de-carbon piston
7. Worn valve guides 6. Repair as
necessary
8. Piston rings fitted 8. Remove rings and
too tightly in grooves check ring end gap
and side clearance.
Replace if necessary
INTAKE MANIFOLD LEAKAGE DIAGNOSIS
An intake manifold air leak is characterized by
lower than normal manifold vacuum. Also, one or
more cylinders may not be functioning.
WARNING: USE EXTREME CAUTION WHEN THE
ENGINE IS OPERATING. DO NOT STAND IN A
DIRECT LINE WITH THE FAN. DO NOT PUT YOUR
HANDS NEAR THE PULLEYS, BELTS, OR THE FAN.
DO NOT WEAR LOOSE CLOTHING.(1) Start the engine.
(2) Spray a small stream of water at the suspected
leak area.
(3) If a change in RPMs, the area of the suspected
leak has been found.
(4) Repair as required.
CYLINDER COMPRESSION PRESSURE TEST
The results of a cylinder compression pressure test
can be utilized to diagnose several engine malfunc-
tions.
DN5.9L ENGINE 9 - 145
DIAGNOSIS AND TESTING (Continued)
Downloaded from www.Manualslib.com manuals search engine 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.
(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 Engine Specifications for the correct
engine compression pressures.
CYLINDER HEAD GASKET FAILURE DIAGNOSIS
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).
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.
CYLINDER COMBUSTION PRESSURE LEAKAGE
TEST
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
jacket
²Any 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.
9 - 146 5.9L ENGINEDN
DIAGNOSIS AND TESTING (Continued)