2003 DODGE RAM spark plugs

CONDITION POSSIBLE CAUSES CORRECTION
12. Faulty ignition coil 12. Test and replace, as necessary (Refer
to 8 - ELECTRICAL/IGNITION CONTROL/
IGNITION COIL - REMOVAL).
ENGINE STALLS OR
ROUGH IDLE1. Carbon build-up on throttle plate 1. Remove throttle body and de-carbon.
(Refer to 14 - FUEL SYSTEM/FUEL
INJECTION/THROTTLE BODY -
REMOVAL).
2. Engine idle speed too low 2. Check Idle Air Control circuit. (Refer to
14 - FUEL SYSTEM/FUEL INJECTION/
IDLE AIR CONTROL MOTOR -
DESCRIPTION)
3. Worn or incorrectly gapped spark plugs 3. Replace or clean and re-gap spark
plugs (Refer to 8 - ELECTRICAL/
IGNITION CONTROL/SPARK PLUG -
CLEANING)
4. Worn or burned distributor rotor 4. Install new distributor rotor
5. Spark plug cables defective or crossed 5. Check for correct firing order or replace
spark plug cables. (Refer to 8 -
ELECTRICAL/IGNITION CONTROL/
SPARK PLUG CABLE - DIAGNOSIS AND
TESTING)
6. Faulty coil 6. Test and replace, if necessary (Refer to
8 - ELECTRICAL/IGNITION CONTROL/
IGNITION COIL - REMOVAL)
7. Intake manifold vacuum leak 7. Inspect intake manifold gasket and
vacuum hoses (Refer to 9 - ENGINE/
MANIFOLDS/INTAKE MANIFOLD -
DIAGNOSIS AND TESTING).
ENGINE MISSES ON
ACCELERATION1. Worn or incorrectly gapped spark plugs 1. Replace spark plugs or clean and set
gap. (Refer to 8 - ELECTRICAL/IGNITION
CONTROL/SPARK PLUG - CLEANING)
2. Spark plug cables defective or crossed 2. Replace or rewire secondary ignition
cables. (Refer to 8 - ELECTRICAL/
IGNITION CONTROL/SPARK PLUG
CABLE - REMOVAL)
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
8 - ELECTRICAL/IGNITION CONTROL/
IGNITION COIL - REMOVAL)
DRENGINE 8.0L 9 - 355
ENGINE 8.0L (Continued)

CONDITION POSSIBLE CAUSES CORRECTION
4. Excessive main bearing clearance 4. Measure bearings for correct
clearance. Repair as necessary
5. Excessive end play 5. Check crankshaft thrust bearing for
excessive wear on flanges
6. Crankshaft main journal out of round
or worn6. Grind journals or replace crankshaft
7. Loose flywheel or torque converter 7. Inspect crankshaft, flexplate/flywheel
and bolts for damage. Tighten to correct
torque
LOW OIL PRESSURE 1. Low oil level 1. Check oil level and fill if necessary
2. Faulty oil pressure sending unit 2. Install new sending unit
3. Clogged oil filter 3. Install new oil filter
4. Worn oil pump 4. Replace oil pump assembly.
5. Thin or diluted oil 5. Change oil to correct viscosity.
6. Excessive bearing clearance 6. Measure bearings for correct
clearance
7. Oil pump relief valve stuck 7. Remove valve to inspect, clean and
reinstall
8. Oil pickup tube loose, broken, bent or
clogged8. Inspect oil pickup tube and pump, and
clean or replace if necessary
9. Oil pump cover warped or cracked 9. Install new oil pump
OIL LEAKS 1. Misaligned or deteriorated gaskets 1. 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 plug 4. Remove and reseal threaded plug.
Replace cup style plug
EXCESSIVE OIL
CONSUMPTION OR
SPARK PLUGS OIL
FOULED1. CCV System malfunction 1. (Refer to 25 - EMISSIONS
CONTROL/EVAPORATIVE EMISSIONS
- DESCRIPTION) for correct operation
2. Defective valve stem seal(s) 2. Repair or replace seal(s)
3. Worn or broken piston rings 3. Hone cylinder bores. Install new rings
4. Scuffed pistons/cylinder walls 4. Hone cylinder bores and replace
pistons as required
5. Carbon in oil control ring groove 5. Remove rings and de-carbon piston
6. Worn valve guides 6. Inspect/replace valve guides as
necessary
7. Piston rings fitted too tightly in
grooves7. Remove rings and check ring end gap
and side clearance. Replace if
necessary
DRENGINE 8.0L 9 - 357
ENGINE 8.0L (Continued)

DIAGNOSIS AND TESTINGÐENGINE DIAGNOSIS - LUBRICATION
CONDITION POSSIBLE CAUSES CORRECTION
OIL LEAKS 1. Gaskets and O-Rings. 1.
(a) Misaligned or damaged. (a) Replace as necessary.
(b) Loose fasteners, broken or
porous metal parts.(b) Tighten fasteners, Repair or
replace metal parts.
2. Crankshaft rear seal 2. Replace as necessary.
3. Crankshaft seal flange.
Scratched, nicked or grooved.3. Polish or replace crankshaft.
4. Oil pan flange cracked. 4. Replace oil pan.
5.Front cover seal, damaged or
misaligned.5. Replace seal.
6. Scratched or damaged vibration
damper hub.6. Polish or replace damper.
OIL PRESSURE DROP 1. Low oil level. 1. Check and correct oil level.
2. Faulty oil pressure sending unit. 2. Replace sending unit.
3. Low oil pressure. 3. Check pump and bearing
clearance.
4. Clogged oil filter. 4. Replace oil filter.
5. Worn oil pump. 5. Replace as necessary.
6. Thin or diluted oil. 6. Change oil and filter.
7. Excessive bearing clearance. 7. Replace as necessary.
8. Oil pump relief valve stuck. 8. Replace oil pump.
9. Oil pickup tube loose or
damaged.9. Replace as necessary.
OIL PUMPING AT RINGS; SPARK
PLUGS FOULING1. Worn or damaged rings. 1. Hone cylinder bores and replace
rings.
2. Carbon in oil ring slots. 2. Replace rings.
3. Incorrect ring size installed. 3. Replace rings.
4. Worn valve guides. 4. Ream guides and replace valves.
5. Leaking intake gasket. 5. Replace intake gaskets.
6. Leaking valve guide seals. 6. Replace valve guide seals.
9 - 358 ENGINE 8.0LDR
ENGINE 8.0L (Continued)

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 TESTING - CYLINDER
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 CYLINDER COMBUSTION
PRESSURE LEAKAGE DIAGNOSIS CHART.
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
DRENGINE 8.0L 9 - 359
ENGINE 8.0L (Continued)

MopartGasket Maker is an anaerobic type gasket
material. The material cures in the absence of air
when squeezed between two metallic surfaces. It will
not cure if left in the uncovered tube. The anaerobic
material is for use between two machined surfaces.
Do not use on flexible metal flanges.
MOPARtGASKET SEALANT
MopartGasket Sealant is a slow drying, perma-
nently soft sealer. This material is recommended for
sealing threaded fittings and gaskets against leakage
of oil and coolant. Can be used on threaded and
machined parts under all temperatures. This mate-
rial is used on engines with multi-layer steel (MLS)
cylinder head gaskets. This material also will pre-
vent corrosion. MopartGasket Sealant is available in
a 13 oz. aerosol can or 4oz./16 oz. can w/applicator.
FORM-IN-PLACE GASKET AND SEALER
APPLICATION
Assembling parts using a form-in-place gasket
requires care but it's easier than using precut gas-
kets.
MopartGasket Maker material should be applied
sparingly 1 mm (0.040 in.) diameter or less of sealant
to one gasket surface. Be certain the material sur-
rounds each mounting hole. Excess material can eas-
ily be wiped off. Components should be torqued in
place within 15 minutes. The use of a locating dowel
is recommended during assembly to prevent smear-
ing material off the location.
MopartEngine RTV GEN II or ATF RTV gasket
material should be applied in a continuous bead
approximately 3 mm (0.120 in.) in diameter. All
mounting holes must be circled. For corner sealing, a
3.17 or 6.35 mm (1/8 or 1/4 in.) drop is placed in the
center of the gasket contact area. Uncured sealant
may be removed with a shop towel. Components
should be torqued in place while the sealant is still
wet to the touch (within 10 minutes). The usage of a
locating dowel is recommended during assembly to
prevent smearing material off the location.
MopartGasket Sealant in an aerosol can should be
applied using a thin, even coat sprayed completely
over both surfaces to be joined, and both sides of a
gasket. Then proceed with assembly. Material in a
can w/applicator can be brushed on evenly over the
sealing surfaces. Material in an aerosol can should be
used on engines with multi-layer steel gaskets.
STANDARD PROCEDURE - REPAIR DAMAGED
OR WORN THREADS
CAUTION: Be sure that the tapped holes maintain
the original center line.Damaged or worn threads can be repaired. Essen-
tially, this repair consists of:
²Drilling out worn or damaged threads.
²Tapping the hole with a special Heli-Coil Tap, or
equivalent.
²Installing an insert into the tapped hole to bring
the hole back to its original thread size.
STANDARD PROCEDUREÐHYDROSTATIC
LOCK
CAUTION: DO NOT use the starter motor to rotate
the crankshaft. Severe damage could occur.
When an engine is suspected of hydrostatic lock
(regardless of what caused the problem), follow the
steps below.
(1) Perform the Fuel Pressure Release Procedure
(Refer to 14 - FUEL SYSTEM/FUEL DELIVERY -
STANDARD PROCEDURE).
(2) Disconnect the negative cable(s) from the bat-
tery.
(3) Inspect air cleaner, induction system, and
intake manifold to ensure system is dry and clear of
foreign material.
(4) Place a shop towel around the spark plugs to
catch any fluid that may possibly be under pressure
in the cylinder head. Remove the spark plugs.
(5) With all spark plugs removed, rotate the crank-
shaft using a breaker bar and socket.
(6) Identify the fluid in the cylinders (coolant, fuel,
oil, etc.).
(7) Be sure all fluid has been removed from the
cylinders.
(8) Repair engine or components as necessary to
prevent this problem from occurring again.
(9) Squirt a small amount of engine oil into the
cylinders to lubricate the walls. This will prevent
damage on restart.
(10) Install new spark plugs. Tighten the spark
plugs to 41 N´m (30 ft. lbs.) torque.
(11) Drain engine oil. Remove and discard the oil
filter.
(12) Install the drain plug. Tighten the plug to 34
N´m (25 ft. lbs.) torque.
(13) Install a new oil filter.
(14) Fill engine crankcase with the specified
amount and grade of oil. (Refer to LUBRICATION &
MAINTENANCE - SPECIFICATIONS).
(15) Connect the negative cable(s) to the battery.
(16) Start the engine and check for any leaks.
REMOVAL
(1) Remove the battery.
(2) Drain cooling system (Refer to 7 - COOLING -
STANDARD PROCEDURE).
DRENGINE 8.0L 9 - 361
ENGINE 8.0L (Continued)

DESCRIPTION N´m Ft. In.
Heat ShieldÐNuts 20 Ð 175
Hydraulic Tappet Yoke
Retaining22 16 Ð
SpiderÐBolts
Intake Manifold (Lower)Ð
Bolts54 40 Ð
Intake Manifold (Upper)Ð
Bolts22 16 Ð
Oil Filter 9 Ð 80 +
45É
Oil Filter Connector 46 34 Ð
Oil Pan
Ð1/4 - 20 Bolts 11 Ð 96
Ð5/16 - 18 Bolts 16 Ð 144
ÐStud Bolts 16 Ð 144
ÐDrain Plug 34 25 Ð
Oil Pan Pick Up TubeÐBolts 16 Ð 144
Oil Pump AttachingÐBolts 41 30 Ð
Oil Pump CoverÐBolts 14 Ð 125
Oil Pump Pressure
ReliefÐPlug20 15 Ð
Rocker ArmÐBolts 54 40 Ð
Spark Plugs 41 30 Ð
Starter MountingÐBolts 68 50 Ð
Timing Chain CoverÐBolts 47 35 Ð
Thermostat HousingÐBolts 25 Ð 220
Throttle BodyÐNuts 11 Ð 96
Transfer Case to Insulator
Mounting204 150 Ð
PlateÐNuts
Transmission Support
BracketÐ102 75 Ð
Bolts
Transmission Support
CushionÐ47 35 Ð
Bolts
Transmission Support
Cushion47 35 Ð
StudÐNuts
Water Pump to Chain Case
CoverÐ41 30 Ð
Bolts8.OL ENGINE
DESCRIPTION SPECIFICATION
CAMSHAFT
Bearing Diameter
No. 1 53.16 ± 53.19 mm
(2.093 ± 2.094 in.)
No. 2 52.76 ± 52.78 mm
(2.077 ± 2.078 in.)
No. 3 52.35 ± 52.37 mm
(2.061 ± 2.062 in.)
No. 4 51.94 ± 51.97 mm
(2.045 ± 2.046 in.)
No. 5 51.54 ± 51.56 mm
(2.029 ± 2.030 in.)
No. 6 48.74 ± 48.77 mm
(1.919 ± 1.920 in.)
Bearing Journal Diameter
No. 1 53.11 ± 53.14 mm
(2.091 ± 2.092 in.)
No. 2 52.69 ± 52.72 mm
(2.0745 ± 2.0755 in.)
No. 3 52.30 ± 52.32 mm
(2.059 ± 2.060 in.)
No. 4 51.89 ± 51.92 mm
(2.043 ± 2.044 in.)
No. 5 51.49 ± 51.51 mm
(2.027 ± 2.028 in.)
No. 6 48.69 ± 48.72 mm
(1.917 ± 1.918 in.)
Bearing to Journal
Clearance
No. 1,3,4,5,6 0.0254 ± 0.0762 mm
(0.001 ± 0.003 in.)
No. 2 0.0381 ± 0.0889 mm
(0.0005 ± 0.0035 in.)
Service Limit 0.127 mm (0.005 in.)
End Play 0.127 ± 0.381 mm
(0.005 ± 0.015 in.)
9 - 364 ENGINE 8.0LDR
ENGINE 8.0L (Continued)

AIR CLEANER ELEMENT
REMOVAL
Filter Element Only
Housing removal is not necessary for element (fil-
ter) replacement.
(1) Loosen clamp (Fig. 4) and disconnect air duct
at air cleaner cover.
(2) Pry over 4 spring clips (Fig. 4) from housing
cover (spring clips retain cover to housing).
(3) Release housing cover from locating tabs on
housing (Fig. 4) and remove cover.
(4) Remove air cleaner element (filter) from hous-
ing.
(5) Clean inside of housing before replacing ele-
ment.
Housing Assembly
(1) Loosen clamp (Fig. 4) and disconnect air duct
at air cleaner cover.
(2) Lift entire housing assembly from 4 locating
pins (Fig. 5).
INSTALLATION
(1) Install filter element into housing.
(2) Position housing cover into housing locating
tabs (Fig. 4).(3) Pry up 4 spring clips (Fig. 4) and lock cover to
housing.
(4) Install air duct to air cleaner cover and tighten
hose clamp to 3 N´m (30 in. lbs.) torque.
(5) If any other hose clamps were removed from
air intake system, tighten them to 3.4 N´m (30 in.
lbs.) torque.
(6) If any bolts were removed from air resonator
housing or air intake tubing, tighten them to 4.5 N´m
(40 in. lbs.) torque.
CYLINDER HEAD
DESCRIPTION
The alloy cast iron cylinder heads (Fig. 6) are held
in place by 12 bolts. The spark plugs are located in
the peak of the wedge between the valves.
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:
þ Loss of engine power
þ Engine misfiring
þ Poor fuel economy
Fig. 4 AIR CLEANER HOUSING COVER
1 - CLAMP
2 - AIR DUCT
3 - AIR CLEANER COVER
4 - LOCATING TABS
5 - CLIPS (4)
Fig. 5 AIR CLEANER HOUSING
1 - AIR CLEANER HOUSING ASSEMBLY
2 - LOCATING PINS (4)
9 - 370 ENGINE 8.0LDR

fuel line (Refer to 14 - FUEL SYSTEM/FUEL DELIV-
ERY/QUICK CONNECT FITTING - STANDARD
PROCEDURE).
(9) Disconnect accelerator linkage and if so
equipped, the speed control and transmission kick-
down cables.
(10) Remove coil pack and bracket (Fig. 8).
(11) Disconnect the coil wires.
(12) Disconnect heat indicator sending unit wire.
(13) Disconnect heater hoses and bypass hose.
(14) Remove upper intake manifold and throttle
body as an assembly (Refer to 9 - ENGINE/MANI-
FOLDS/INTAKE MANIFOLD - REMOVAL).
(15) Remove cylinder head covers and gaskets
(Refer to 9 - ENGINE/CYLINDER HEAD/CYLIN-
DER HEAD COVER(S) - REMOVAL).
(16) Remove the EGR tube. Discard the gasket, for
right side only.
(17) Remove lower intake manifold (Refer to 9 -
ENGINE/MANIFOLDS/INTAKE MANIFOLD -
REMOVAL). Discard the flange side gaskets and the
front and rear cross-over gaskets.
(18) Disconnect exhaust pipe from exhaust mani-
fold.
(19) Remove exhaust manifolds and gaskets (Refer
to 9 - ENGINE/MANIFOLDS/EXHAUST MANIFOLD
- REMOVAL).
(20) Remove rocker arm assemblies and push rods
(Refer to 9 - ENGINE/CYLINDER HEAD/ROCKER
ARM / ADJUSTER ASSY - REMOVAL). Identify to
ensure installation in original locations.(21) Remove the head bolts from each cylinder
head and remove cylinder heads. Discard the cylin-
der head gasket.
(22) Remove spark plugs.
CLEANING
Clean all surfaces of cylinder block and cylinder
heads. Be sure material does not fall into the lifters
and surrounding valley.
Clean cylinder block front and rear gasket surfaces
using a suitable solvent.
Clean the exhaust manifold to cylinder head mat-
ing areas.
INSPECTION
Inspect all surfaces with a straightedge if there is
any reason to suspect leakage. The out-of-flatness
specifications are 0.0007 mm/mm (0.0004 inch/inch),
0.127 mm/152 mm (0.005 inch/6 inches) any direction
or 0.254 mm (0.010 inch) overall across head. If
exceeded, either replace head or lightly machine the
head surface.
The cylinder head surface finish should be
1.78-4.57 microns (15-80 microinches).
Inspect push rods. Replace worn or bent rods.
Inspect rocker arms. Replace if worn or scored.
INSTALLATION
(1) Position the new cylinder head gaskets onto
the cylinder block.
(2) Position the cylinder heads onto head gaskets
and cylinder block.
(3) Tighten the cylinder head bolts in two steps
(Fig. 9):
²Step 1ÐTighten all cylinder head bolts, in
sequence, to 58 N´m (43 ft. lbs.) torque.
²Step 2ÐTighten all cylinder head bolts, in
sequence, to 143 N´m (105 ft. lbs.) torque.
²
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.
Fig. 8 Coil Pack and Bracket
1 - COIL PACKS AND BRACKET
2 - MOUNTING BOLTS (4)
Fig. 9 Cylinder Head Bolt Tightening Sequence
9 - 372 ENGINE 8.0LDR
CYLINDER HEAD (Continued)