Seat DODGE DURANGO 1999 1.G Owner's Manual

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 spring seat in cylinder head to the bottom surface of
spring retainer. If spacers are installed, measure
from the top of spacer. If height is greater than 42.86
mm (1-11/16 inches), install a 1.587 mm (1/16 inch)
spacer in head counterbore. This should bring spring
height back to normal 41.27 to 42.86 mm (1-5/8 to
1-11/16 inch).
HYDRAULIC TAPPETS
REMOVAL
(1) Remove the air cleaner assembly and air inlet
hose.
(2) Remove cylinder head cover, rocker assembly
and push rods. Identify push rods to ensure installa-
tion in original location.
(3) Remove intake manifold, yoke retainer and
aligning yokes.
(4) Slide Hydraulic Tappet Remover/Installer Tool
C-4129-A through opening in cylinder head and seat
tool firmly in the head of tappet.
(5) Pull tappet out of bore with a twisting motion.
If all tappets are to be removed, identify tappets to
ensure installation in original location.
INSTALLATION
(1) If the tappet or bore in cylinder block is scored,
scuffed, or shows signs of sticking, ream the bore to
next oversize. Replace with oversize tappet.
(2) Lubricate tappets.
(3) Install tappets and push rods in their original
positions. Ensure that the oil feed hole in the side of
the tappet body faces up (away from the crankshaft).
(4) Install aligning yokes with ARROW toward
camshaft.
(5) Install yoke retainer. Tighten the bolts to 23
N´m (200 in. lbs.) torque. Install intake manifold.
(6) Install push rods in original positions.
(7) Install rocker arm.
(8) Install cylinder head cover.
(9) Install air cleaner assembly and air inlet hose.
(10) Start and operate engine. Warm up to normal
operating temperature.
CAUTION: To prevent damage to valve mechanism,
engine must not be run above fast idle until all
hydraulic tappets have filled with oil and have
become quiet.
VIBRATION DAMPER
REMOVAL
(1) Disconnect the negative cable from the battery.
(2) Remove fan shroud retainer bolts and set
shroud back over engine.(3) Remove the cooling system fan.
(4) Remove the serpentine belt (refer to Group 7,
Cooling System).
(5) Remove the vibration damper pulley.
(6) Remove vibration damper bolt and washer from
end of crankshaft.
(7) Install bar and screw from Puller Tool Set
C-3688. Install 2 bolts with washers through the
puller tool and into the vibration damper (Fig. 46).
(8) Pull vibration damper off of the crankshaft.
INSTALLATION
(1) Position the vibration damper onto the crank-
shaft.
(2) Place installing tool, part of Puller Tool Set
C-3688 in position and press the vibration damper
onto the crankshaft (Fig. 47).
(3) Install the crankshaft bolt and washer. Tighten
the bolt to 183 N´m (135 ft. lbs.) torque.
(4) Install the crankshaft pulley. Tighten the pul-
ley bolts to 23 N´m (200 in. lbs.) torque.
(5) Install the serpentine belt (refer to Group 7,
Cooling System).
(6) Install the cooling system fan. Tighten the
bolts to 23 N´m (17 ft. lbs.) torque.
Fig. 46 Vibration Damper Assembly
1 ± SPECIAL TOOL C-3688
Fig. 47 Installing Vibration Damper
1 ± SPECIAL TOOL C-3688
DN5.2L ENGINE 9 - 109
REMOVAL AND INSTALLATION (Continued)

Downloaded from www.Manualslib.com manuals search engine (7) Position the fan shroud and install the bolts.
Tighten the retainer bolts to 11 N´m (95 in. lbs.)
torque.
(8) Connect the negative cable to the battery.
TIMING CHAIN COVER
(1) Disconnect the negative cable from the battery.
(2) Drain cooling system (refer to Group 7, Cooling
System).
(3) Remove the serpentine belt (refer to Group 7,
Cooling System).
(4) Remove water pump (refer to Group 7, Cooling
System).
(5) Remove power steering pump (refer to Group
19, Steering).
(6) Remove vibration damper.
(7) Remove fuel lines (refer to Group 14, Fuel Sys-
tem).
(8) Loosen oil pan bolts and remove the front bolt
at each side.
(9) Remove the cover bolts.
(10) Remove chain case cover and gasket using
extreme caution to avoid damaging oil pan gasket.
(11) Place a suitable tool behind the lips of the oil
seal to pry the oil seal outward. Be careful not to
damage the crankshaft seal surface of cover (Fig. 48).
INSTALLATION
(1) Be sure mating surfaces of chain case cover
and cylinder block are clean and free from burrs.
(2) The water pump mounting surface must be
cleaned.
(3) Using a new cover gasket, carefully install
chain case cover to avoid damaging oil pan gasket.
Use a small amount of Mopar Silicone Rubber Adhe-
sive Sealant, or equivalent, at the joint between tim-
ing chain cover gasket and the oil pan gasket. Finger
tighten the timing chain cover bolts at this time.
(4) Place the smaller diameter of the oil seal over
Front Oil Seal Installation Tool 6635 (Fig. 49). Seat
the oil seal in the groove of the tool.
(5) Position the seal and tool onto the crankshaft
(Fig. 50).(6) Tighten the 4 lower chain case cover bolts to
13N´m (10 ft.lbs.) to prevent the cover from tipping
during seal installation.
(7) Using the vibration damper bolt, tighten the
bolt to draw the seal into position on the crankshaft
(Fig. 51).
(8) Loosen the 4 bolts tightened in step 4 to allow
realignment of front cover assembly.
Fig. 48 Removal of Front Crankshaft Oil Seal
Fig. 49 Placing Oil Seal on Installation Tool 6635
1 ± CRANKSHAFT FRONT OIL SEAL
2 ± INSTALL THIS END INTO SPECIAL TOOL 6635
Fig. 50 Position Tool and Seal onto Crankshaft
1 ± SPECIAL TOOL 6635
2 ± OIL SEAL
3 ± TIMING CHAIN COVER
9 - 110 5.2L ENGINEDN
REMOVAL AND INSTALLATION (Continued)

Downloaded from www.Manualslib.com manuals search engine interference. If tool does not fit, the cover must be
removed and installed properly.
(4) Place a suitable tool behind the lips of the oil
seal to pry the oil seal outward. Be careful not to
damage the crankshaft seal bore of cover.
(5) Place the smaller diameter of the oil seal over
Front Oil Seal Installation Tool 6635 (Fig. 68). Seat
the oil seal in the groove of the tool.
(6) Position the seal and tool onto the crankshaft
(Fig. 69).
(7) Using the vibration damper bolt, tighten the
bolt to draw the seal into position on the crankshaft
(Fig. 70).
(8) Remove the vibration damper bolt and seal
installation tool.
(9) Inspect the seal flange on the vibration
damper.
(10) Install the vibration damper.
(11) Connect the negative cable to the battery.
CRANKSHAFT OIL SEALSÐREAR
The service seal is a 2 piece, viton seal. The upper
seal half can be installed with crankshaft removed
from engine or with crankshaft installed. When a
new upper seal is installed, install a new lower seal.
The lower seal half can only be installed with the
rear main bearing cap removed.
UPPER SEAL ÐCRANKSHAFT REMOVED
REMOVAL
(1) Remove the crankshaft. Discard the old upper
seal.
INSTALLATION
(1) Clean the cylinder block rear cap mating sur-
face. Make sure the seal groove is free of debris.
Fig. 68 Placing Oil Seal on Installation Tool 6635
1 ± CRANKSHAFT FRONT OIL SEAL
2 ± INSTALL THIS END INTO SPECIAL TOOL 6635
Fig. 69 Position Tool and Seal onto Crankshaft
1 ± SPECIAL TOOL 6635
2 ± OIL SEAL
3 ± TIMING CHAIN COVER
Fig. 70 Installing Oil Seal
1 ± SPECIAL TOOL 6635
2 ± TIMING CHAIN COVER
9 - 118 5.2L ENGINEDN
REMOVAL AND INSTALLATION (Continued)

Downloaded from www.Manualslib.com manuals search engine DISASSEMBLY AND ASSEMBLY
VALVE SERVICE
VALVE GUIDES
Measure valve stem guide clearance as follows:
(1) Install Valve Guide Sleeve Tool C-3973 over
valve stem and install valve (Fig. 75). The special
sleeve places the valve at the correct height for
checking with a dial indicator.(2) Attach Dial Indicator Tool C-3339 to cylinder
head and set it at right angle of valve stem being
measured (Fig. 76).
(3) Move valve to and from the indicator. The total
dial indicator reading should not exceed 0.432 mm
(0.017 inch). Ream the guides for valves with over-
size stems if dial indicator reading is excessive or if
the stems are scuffed or scored.
(4) Service valves with oversize stems are avail-
able as shown below.
(5) Slowly turn reamer by hand and clean guide
thoroughly before installing new valve.Ream the
valve guides from standard to 0.381 mm (0.015
inch). Use a 2 step procedure so the valve
guides are reamed true in relation to the valve
seat:
²Step 1ÐReam to 0.0763 mm (0.003 inch).
²Step 2ÐReam to 0.381 mm (0.015 inch).
Fig. 74 Core Hole Plug Removal
1 ± CYLINDER BLOCK
2 ± REMOVE PLUG WITH PLIERS
3 ± STRIKE HERE WITH HAMMER
4 ± DRIFT PUNCH
5 ± CUP PLUG
Fig. 75 Positioning Valve with Tool C-3973
1 ± VALVE
2 ± SPACER TOOL
Fig. 76 Measuring Valve Guide Wear
1 ± VALVE
2 ± SPECIAL TOOL C-3339
REAMER SIZES CHART
REAMER O/S VALVE GUIDE SIZE
0.076 mm 8.026 - 8.052 mm
(0.003 in.) (0.316 - 0.317 in.)
0.381 mm 8.331 - 8.357 mm
(0.015 in.) (0.328 - 0.329 in.)
DN5.2L ENGINE 9 - 121
REMOVAL AND INSTALLATION (Continued)

Downloaded from www.Manualslib.com manuals search engine REFACING VALVES AND VALVE SEATS
The intake and exhaust valves have a 43-1/4É to
43-3/4É face angle and a 44-1/4É to 44-3/4É seat angle
(Fig. 77).
VALVES
Inspect the remaining margin after the valves are
refaced (Fig. 78). Valves with less than 1.190 mm
(0.047 inch) margin should be discarded.VALVE SEATS
CAUTION: DO NOT un-shroud valves during valve
seat refacing (Fig. 79).
(1) When refacing valve seats, it is important that
the correct size valve guide pilot be used for reseat-
ing stones. A true and complete surface must be
obtained.
Fig. 77 Valve Face and Seat Angles
1 ± CONTACT POINT
ITEM DESCRIPTION SPECIFICATION
ASEAT WIDTH - 1.016 - 1.524
mm
INTAKE (0.040 - 0.060
in.)
EXHAUST 1.524 - 2.032
mm
(0.060 - 0.080
in.)
BFACE ANGLE
(INT. AND
EXT.)43
1¤4É-433¤4É
CSEAT ANGLE
(INT. AND
EXT.)44
1¤4É-443¤4É
DCONTACT
SURFACE Ð
Fig. 78 Intake and Exhaust Valves
1 ± MARGIN
2 ± VALVE SPRING RETAINER LOCK GROOVE
3 ± STEM
4±FACE
Fig. 79 Refacing Valve Seats
1±STONE
2 ± PILOT
3 ± VALVE SEAT
4 ± SHROUD
9 - 122 5.2L ENGINEDN
DISASSEMBLY AND ASSEMBLY (Continued)

Downloaded from www.Manualslib.com manuals search engine (2) Measure the concentricity of valve seat using a
dial indicator. Total runout should not exceed 0.051
mm (0.002 inch) total indicator reading.
(3) Inspect the valve seat with Prussian blue to
determine where the valve contacts the seat. To do
this, coat valve seat LIGHTLY with Prussian blue
then set valve in place. Rotate the valve with light
pressure. If the blue is transferred to the center of
valve face, contact is satisfactory. If the blue is trans-
ferred to the top edge of valve face, lower valve seat
with a 15É stone. If the blue is transferred to bottom
edge of valve face raise valve seat with a 60É stone.
(4) When seat is properly positioned the width of
intake seats should be 1.016-1.524 mm (0.040-0.060
inch). The width of the exhaust seats should be
1.524-2.032 mm (0.060-0.080 inch).
VALVE SPRING INSPECTION
Whenever valves have been removed for inspection,
reconditioning or replacement, valve springs should
be tested. As an example the compression length of
the spring to be tested is 1-5/16 inch. Turn table of
Universals Valve Spring Tester Tool until surface is
in line with the 1-5/16 inch mark on the threaded
stud. Be sure the zero mark is to the front (Fig. 80).
Place spring over stud on the table and lift compress-
ing lever to set tone device. Pull on torque wrench
until ping is heard. Take reading on torque wrench
at this instant. Multiply this reading by 2. This will
give the spring load at test length. Fractional mea-
surements are indicated on the table for finer adjust-
ments. Refer to specifications to obtain specified
height and allowable tensions. Discard the springs
that do not meet specifications.
OIL PUMP
DISASSEMBLE
(1) Remove the relief valve as follows:
(a) Remove cotter pin. Drill a 3.175 mm (1/8
inch) hole into the relief valve retainer cap and
insert a self-threading sheet metal screw.
(b) Clamp screw into a vise and while support-
ing oil pump, remove cap by tapping pump body
using a soft hammer. Discard retainer cap and
remove spring and relief valve (Fig. 81).
(2) Remove oil pump cover (Fig. 82).
(3) Remove pump outer rotor and inner rotor with
shaft (Fig. 82).
(4) Wash all parts in a suitable solvent and inspect
carefully for damage or wear.
ASSEMBLE
(1) Install pump rotors and shaft, using new parts
as required.
(2) Position the oil pump cover onto the pump
body. Tighten cover bolts to 11 N´m (95 in. lbs.)
torque.
(3) Install the relief valve and spring. Insert the
cotter pin.
(4) Tap on a new retainer cap.
(5) Prime oil pump before installation by filling
rotor cavity with engine oil.
Fig. 80 Testing Valve Spring for Compressed
Length
1 ± TORQUE WRENCH
2 ± VALVE SPRING TESTER
Fig. 81 Oil Pressure Relief Valve
1 ± OIL PUMP ASSEMBLY
2 ± COTTER PIN
3 ± RELIEF VALVE
4 ± RETAINER CAP
5 ± SPRING
DN5.2L ENGINE 9 - 123
DISASSEMBLY AND ASSEMBLY (Continued)

Downloaded from www.Manualslib.com manuals search engine DESCRIPTION SPECIFICATION
Main Bearing Journal
Diameter 63.487 ± 63.513 mm
(2.4995 ± 2.5005 in.)
Out of Round (Max.) 0.127 mm
(0.001 in.)
Taper (Max.) 0.0254 mm
(0.001 in.)
Bearing Clearance
(#1 Journal) 0.013 ± 0.038 mm
(0.0005 ± 0.0015 in.)
(#2-5 Journals) 0.013 ± 0.051 mm
(0.0005 ± 0.002 in.)
Service Limit
(#1 Journal) 0.0381 mm
(0.0015 in.)
(#2-5 Journals) 0.064 mm
(0.0025 in.)
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 99.308 ± 99.371 mm
(3.9098 ± 3.9122 in.)
Out of Round (Max.) 0.025 mm
(0.001 in.)
Taper (Max.) 0.025 mm
(0.001 in.)
Oversize Limit 1.016 mm
(0.040 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.)DESCRIPTION SPECIFICATION
CYLINDER HEAD
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.)
VA LV E S
Face Angle 43.25É ± 43.75É
Head Diameter
Intake 48.666 mm
(1.916 in.)
Exhaust 41.250 mm
(1.624 in.)
Length (Overall)
Intake 124.28 ± 125.92 mm
(4.893 ± 4.918 in.)
Exhaust 124.64 ± 125.27 mm
(4.907 ± 4.932 in.)
Lift (@ zero lash) 10.973 mm
(0.432 in.)
Stem Diameter 7.899 ± 7.925 mm
(0.311 ± 0.312 in.)
Guide Bore 7.950 ± 7.976 mm
(0.313 ± 0.314 in.)
Stem to Guide Clearance 0.0254 ± 0.0762 mm
(0.001 ± 0.003 in.)
Service Limit (rocking
method)0.4318 mm
(0.017 in.)
DN5.2L ENGINE 9 - 129
SPECIFICATIONS (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 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)