reference marks on torque converter and flexplate are aligned.
Evacuate and charge A/C system.
Removal (Durango 4WD & Dakota 4WD)
1) Release fuel pressure. See FUEL PRESSURE RELEASE.
Disconnect and remove battery. Scribe hood hinges for installation
reference and remove hood.
2) Drain cooling system. Disconnect coolant hoses. Remove
radiator, fan and shroud. Discharge A/C system (if equipped) using
approved refrigerant recovery/recycling equipment. Disconnect A/C
lines, and plug openings. Remove air cleaner, vacuum lines,
distributor cap and wiring.
3) Disconnect necessary electrical wiring. Disconnect fuel
lines. See FUEL LINE DISCONNECT FITTINGS. Disconnect accelerator
linkage. Remove throttle body. Remove starter and generator.
Disconnect power steering hoses. Raise and support vehicle. Drain oil.
Disconnect exhaust pipe at exhaust manifold.
NOTE: Engine, transmission and front axle are connected and
supported with insulators and brackets. See Fig. 3.
4) On left side, remove 2 bolts attaching differential pinion
nose bracket-to-bellhousing bolts. Remove pinion nose bracket-to-
adapter bolts (located on top of differential, near pinion). Separate
engine from engine mount by removing engine mount through-bolt and nut
located on top of engine mount.
5) On right side, remove 2 axle-to-bracket bolts and bracket-
to-bellhousing bolt. Separate engine from engine mount by removing
engine mount through-bolt and nut located on top of engine mount.
Remove engine from vehicle.
CYLINDER HEAD
Cylinder Head
Check cylinder head warpage. Repair or replace cylinder head
if warpage exceeds specification. See CYLINDER HEAD table under ENGINE
SPECIFICATIONS.
Valve Springs
1) Check valve spring free length, out-of-square and
pressure. Replace valve spring if not within specification. See VALVES
& VALVE SPRINGS table under ENGINE SPECIFICATIONS.
2) Measure valve spring installed height from bottom of
spring seat (cylinder head surface) to bottom of spring retainer. If
spacers are installed, measure from top of spacer.
3) If height exceeds 1.687" (42.86 mm), install a .066" (1.\
58
mm) thick spacer in cylinder head counterbore to obtain correct
installed spring height. See VALVES & VALVE SPRINGS table.
Valve Stem Oil Seals
Cup-type oil seals are used on all valves. Ensure oversize
valve stem oil seals are used when oversize valves are installed. When
installing valves, DO NOT overcompress valve springs, or damage to
valve stem oil seal may result.
NOTE: DO NOT ream valve guides from standard to maximum oversize in
one step. Ream valve guides to oversize in gradual steps so
guides are reamed true in relation to valve seat. After
reaming valve guides, valve seat runout must be checked.
Valve Guides
Check valve stem oil clearance. Ensure valve stem diameter is
within specification. Valve guide must be reamed for valve with
oversize valve stem if oil clearance exceeds specification. See
CYLINDER HEAD table under ENGINE SPECIFICATIONS. Valves are available
with stems of .015" (.38 mm) and .030" (.76 mm) oversize.
Valve Seat
Check valve seat width and runout. Grind valve seat if not
within specification. See CYLINDER HEAD table under ENGINE
SPECIFICATIONS.
Valves
Ensure valve margin, head diameter and stem diameter are
within specification. See VALVES & VALVE SPRINGS table under ENGINE
SPECIFICATIONS. Valves are available with stems of .015" (.38 mm) and
.030" (.76 mm) oversize.
Valve Seat Correction Angles
Use a 15-degree stone to lower valve seat, and a 60-degree
stone to raise valve seat.
VALVE TRAIN
Rocker Arms & Pivots
Remove rocker arms and pivots. Inspect for wear. Replace as
necessary.
NOTE: Cylinder block must be marked to indicate oversize valve
lifters. See SPECIAL ENGINE MARKS.
Valve Lifters
Measure valve lifter diameter and bore diameter in cylinder
2) Ensure journal diameter, taper and out-of-round are within
specification. See CRANKSHAFT, MAIN & CONNECTING ROD BEARINGS table
under ENGINE SPECIFICATIONS. Upper main bearings contain oil holes,
while lower bearings installed in main bearing cap do not.
3) Apply light coat of engine oil to threads before
tightening bolt to specification. See TORQUE SPECIFICATIONS table.
Ensure oil clearance and end play are within specification. See
CRANKSHAFT, MAIN & CONNECTING ROD BEARINGS table.
CAUTION: Crankshaft journal grinding should not exceed .012" (.30 mm)
under standard size. DO NOT grind thrust surfaces of No. 3
main bearing. Final paper or cloth polishing after regrind
must be done in same direction as engine rotation.
Thrust Bearing
Thrust bearing is located on No. 3 main bearing. Replace
thrust bearing if crankshaft end play is not within specification. See
CRANKSHAFT, MAIN & CONNECTING ROD BEARINGS table under ENGINE
SPECIFICATIONS.
NOTE: Cylinder bore should be measured at room temperature of 70
F
(21C).
Cylinder Block
1) Check cylinder bore, out-of-round and taper. Measure
cylinder bore diameter below top surface of cylinder bore, middle of
bore and bottom of cylinder bore. Bore cylinder block if bore diameter
is not within specification. See CYLINDER BLOCK table under ENGINE
SPECIFICATIONS.
NOTE: Cylinder block is marked to indicate oversize valve lifters.
See SPECIAL ENGINE MARKS.
2) Check valve lifter bore diameter. Check for scoring. If
scoring exists or lifter bore diameter is not within specification,
ream cylinder block bore for next oversize valve lifter. See VALVE
LIFTERS table under ENGINE SPECIFICATIONS.
ENGINE OILING
ENGINE LUBRICATION SYSTEM
System has a rotor-type oil pump and full-flow oil filter.
Oil is forced by pump through a series of oil passages in engine to
provide lubrication to engine components. Oil is supplied to rocker
assembly through hollow push rods. Push rods are fed oil from lifters.
See Fig. 17 .
Crankcase Capacity
On 3.9L, oil capacity with oil filter is 4.0 qts. (3.8L). On
5.2L and 5.9L, oil capacity with oil filter is 5.0 qts. (4.7L).
Oil Pressure
Oil pressure is 6 psi (.4 kg/cm
) at idle and 30-80 psi (2.1-
5.6 kg/cm) at 3000 RPM with engine at normal operating temperature.
Fig. 17: Cross-Sectional View Of Engine Oil Circuit
Courtesy of Chrysler Corp.
OIL LINE PLUG
1) The oil line plug is located in vertical passage in rear
of block between oil-to-filter and oil-from-filter passages. See
Fig. 18 . Missing or improperly installed plug could cause erratic, low
or no oil pressure.
2) To check installation, remove oil sending unit and insert
wire down passage. Oil line plug should be 7.50-7.68 in. (190.0-195.2
mm) from machined surface of block. If plug is too high, use suitable
dowel to position properly. If plug is too low, remove oil pan, oil
pump and rear main bearing cap. Use suitable dowel to position
properly.
3) To remove for passage cleaning or plug replacement, drive
plug from oil sending unit hole out bottom of block. When installing
3.9L & 5.2L .......................... .9841-9843 (24.996-25.001)\
5.9L .................................. .9845-9848 (25.006-25.013)\
Length
3.9L & 5.2L ........................... 2.99-3.01 (75.946-76.454)\
5.9L ....................................... 2.67-2.69 (67.8-68.3)\
Piston Fit
3.9L & 5.2L ......................... .00025-.00075 (.0064-.0191)\
5.9L ..................................... .0002-.0007 (.005-.018)\
Rod Fit .............................. (1) .0007-.0014 (.018-.036)
Rings
3.9L & 5.2L
No. 1 & No. 2
End Gap ................................. .010-.020 (.254-.508)\
Side Clearance ........................ .0029-.0038 (.074-.097)\
No. 3 (Oil)
End Gap .................................. .010-.050 (.25-1.27)\
Side Clearance .................... ( 2) .002-.008 (.06-21) Max.
5.9L
No. 1
End Gap ................................... .012-.022 (.30-.55)\
Side Clearance ........................ .0016-.0033 (.041-.084)\
No. 2
End Gap ................................... .022-.031 (.30-.79)\
Side Clearance ........................ .0016-.0033 (.041-.084)\
No. 3 (Oil)
End Gap .................................. .015-.055 (.38-1.40)\
Side Clearance .......................... ( 2) .0080 (.203) Max.
( 1) - Interference fit.
( 2) - Steel rail oil ring should be free in groove, but clearance
within maximum specification.
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VALVES & VALVE SPRINGS \
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Application Specification
Intake Valves
Face Angle .......................................... 43.25-43.75
Head Diameter
3.9L & 5.2L ................................... 1.916" (48.66 mm)\
5.9L .......................................... 1.880" (47.75 mm)\
Minimum Margin ................................... .047" (1.19 mm)\
Stem Diameter
3.9L & 5.2L ........................... .311-.312" (7.90-7.92 mm)\
5.9L .................................. .372-.373" (9.45-9.47 mm)\
Exhaust Valves
Face Angle .......................................... 43.25-43-75
Head Diameter
3.9L & 5.2L ................................... 1.624" (41.25 mm)\
5.9L .......................................... 1.617" (41.07 mm)\
Minimum Margin ................................... .047" (1.19 mm)\
Stem Diameter
3.9L & 5.2L ........................... .311-.313" (7.90-7.95 mm)\
5.9L .................................. .371-.372" (9.42-9.45 mm)\
Valve Springs
Free Length .................................... 1.967" (49.96 mm)\
Installed Height ................... 1.625-1.687" (41.28-42.85 mm)\
Lbs. @ In. (kg @ mm)
Pressure
Valve Closed ............................ 85 @ 1.640 (38 @ 41.66)\
rust may be removed using bead blasting method. Components must be
free of oil and grease prior to bead blasting. Beads will stick to
grease or oil soaked areas causing area not to be cleaned.
Use air pressure to remove all trapped residual beads from
components after cleaning. After cleaning internal engine parts made
of aluminum, wash thoroughly with hot soapy water. Component must be
thoroughly cleaned as glass beads will enter engine oil resulting in
bearing damage.
CHEMICAL CLEANING
Solvent tank is used for cleaning oily residue from
components. Solvent blasting sprays solvent through a siphon gun using
compressed air.
The hot tank, using heated caustic solvents, is used for
cleaning ferrous materials only. DO NOT clean aluminum parts such as
cylinder heads, bearings or other soft metals using the hot tank.
After cleaning, flush parts with hot water.
A non-ferrous part will be ruined and caustic solution will
be diluted if placed in the hot tank. Always use eye protection and
gloves when using the hot tank.
Use of a cold tank is for cleaning of aluminum cylinder
heads, carburetors and other soft metals. A less caustic and unheated
solution is used. Parts may be lift in the tank for several hours
without damage. After cleaning, flush parts with hot water.
Steam cleaning, with boiling hot water sprayed at high
pressure, is recommended as the final cleaning process when using
either hot or cold tank cleaning.
COMPONENT CLEANING
* PLEASE READ THIS FIRST *
NOTE: Always refer to appropriate engine overhaul article in the
ENGINES section for complete overhaul procedures and
specifications for the vehicle being repaired.
SHEET METAL PARTS
Examples of sheet metal parts are the rocker covers, front
and side covers, oil pan and bellhousing dust cover. Glass bead
blasting or hot tank may be used for cleaning.
Ensure all mating surfaces are flat. Deformed surfaces should
be straightened. Check all sheet metal parts for cracks and dents.
INTAKE & EXHAUST MANIFOLDS
Using solvent cleaning or bead blasting, clean manifolds for
inspection. If the intake manifold has an exhaust crossover, all
carbon deposits must be removed. Inspect manifolds for cracks, burned
or eroded areas, corrosion and damage to fasteners.
Exhaust heat and products of combustion cause threads of
fasteners to corrode. Replace studs and bolts as necessary. On "V"
type intake manifolds, the sheet metal oil shield must be removed for
proper cleaning and inspection. Ensure that all manifold parting
surfaces are flat and free of burrs.
CYLINDER HEAD REPLACEMENT
* PLEASE READ THIS FIRST *
than .010" (.25 mm) from tip. Chamfer sharp edge of reground valve
tip. Recheck valve stem installed height.
VALVE STEM OIL SEALS
Valve stem oil seals must be installed on valve stem. See
Fig. 2 . Seals are needed due to pressure differential at the ends of
valve guides. Atmospheric pressure above intake guide, combined with
manifold vacuum below guide, causes oil to be drawn into the cylinder.
Exhaust guides also have pressure differential created by
exhaust gas flowing past the guide, creating a low pressure area. This
low pressure area draws oil into the exhaust system.
Replacement (On Vehicle)
Mark rocker arm or overhead cam components for location.
Remove rocker arm components or overhead cam components. Components
must be installed in original location. Remove spark plugs. Valve stem
oil seals may be replaced by holding valves against seats using air
pressure.
Air pressure must be installed in cylinder using an adapter
for spark plug hole. An adapter can be constructed by welding air hose
connection to spark plug body with porcelain removed.
Install adapter in spark plug hole. Apply a minimum of 140
psi (9.8 kg/cm
) to adapter. Air pressure should hold valve closed. If
air pressure does not hold valve closed, check for damaged or bent
valve. Cylinder head must be removed for service.
Using valve spring compressor, compress valve springs. Remove
valve locks. Carefully release spring compressor. Remove retainer or
rotator and valve spring. Remove valve stem oil seal.
If oversized valves have been installed, oversized oil seals
must be used. Coat valve stem with engine oil. Install protective
sleeve over end of valve stem. Install new oil seal over valve stem
and seat on valve guide. Remove protective sleeve. Install spring
seat, valve spring and retainer or rotator. Compress spring and
install valve locks. Remove spring compressor. Ensure valve locks
are fully seated.
Install rocker arms or overhead cam components. Tighten all
bolts to specification. Adjust valves if required. Remove adapter.
Install spark plugs, valve cover and gasket.
VALVE SPRING INSTALLED HEIGHT
Valve spring installed height should be checked during
reassembly. Measure height from lower edge of valve spring to the
upper edge. DO NOT include valve spring seat or retainer. Distance
must be within specifications. If valves and/or seats have been
ground, a valve spring shim may be required to correct spring height.
See Fig. 12 .
Fig. 12: Measuring Valve Spring Installed Height - Typical
This Graphic For General Information Only
Engine pre-oiling can be done using pressure oiler (if
available). Connect pressure oiler to cylinder block oil passage
such as oil pressure sending unit. Operate pressure oiler long enough
to ensure correct amount of oil has filled crankcase. Check oil level
while pre-oiling.
If pressure oiler is not available, disconnect ignition
system. Remove oil pressure sending unit and replace with oil pressure
test gauge. Using starter motor, rotate engine starter until gauge
shows normal oil pressure for several seconds. DO NOT crank engine
for more than 30 seconds to avoid starter motor damage.
Ensure oil pressure has reached the most distant point from
the oil pump. Reinstall oil pressure sending unit. Reconnect ignition
system.
INITIAL START-UP
Start the engine and operate engine at low speed while
checking for coolant, fuel and oil leaks. Stop engine. Recheck coolant
and oil level. Adjust if necessary.
CAMSHAFT
Break-in procedure is required when a new or reground
camshaft has been installed. Operate and maintain engine speed between
1500-2500 RPM for approximately 30 minutes. Procedure may vary due to
manufacturers recommendations.
PISTON RINGS
Piston rings require a break-in procedure to ensure seating
of rings to cylinder walls. Serious damage may occur to rings if
correct procedures are not followed.
Extremely high piston ring temperatures are produced obtained
during break-in process. If rings are exposed to excessively high RPM
or high cylinder pressures, ring damage can occur. Follow piston ring
manufacturer's recommended break-in procedure.
FINAL ADJUSTMENTS
Check or adjust ignition timing and dwell (if applicable).
Adjust valves (if necessary). Adjust carburetion or injection idle
speed and mixture. Retighten cylinder heads (if required). If
cylinder head or block is aluminum, retighten bolts when engine is
cold. Follow the engine manufacturer's recommended break-in procedure
and maintenance schedule for new engines.
NOTE: Some manufacturer's require that head bolts be retightened
after specified amount of operation. This must be done to
prevent head gasket failure.