2003 DODGE RAM app

DESCRIPTION SPECIFICATION
Length (Overall)
Intake 113.45 - 114.21 mm
(4.4666 - 4.4965)
Exhaust 114.92 - 115.68 mm
(4.5244 - 4.5543 in.)
Stem Diameter
Intake 6.931 - 6.957 mm
(0.2729 - 0.2739 in.)
Exhaust 6.902 - 6.928 mm
(0.2717 - 0.2728 in.)
Stem - to - Guide
Clearance
Intake 0.018 - 0.069 mm
(0.0008 - 0.0028 in.)
Exhaust 0.047 - 0.098 mm
(0.0019 - 0.0039 in.)
Max. Allowable Stem -
to -
Guide Clearance
(Rocking
Method)
Intake 0.069 mm (0.0028 in.)
Exhaust 0.098 mm (0.0039 in.)
Valve Lift (Zero Lash)
Intake 12.00 mm (0.472 in.)
Exhaust 10.90 mm (0.4292 in.)
VALVE SPRING
Free Length (Approx)
Intake 48.92 mm (1.9260 in.)
Exhaust 49.81 mm (1.9610 in.)
Spring Force (Valve
Closed)
Intake 361.0 - 390.0 N @ 40.12
mm
(81.15 - 87.67 lbs. @
1.5795 in.)
Exhaust 390.0 - 430.0 N @ 40.12
mm
(87.67 - 96.66 lbs. @
1.5795 in.)DESCRIPTION SPECIFICATION
Spring Force (Valve
Open)
Intake 984.0 - 1040.0 N @
28.12 mm
221.2 - 233.8 lbs. @
1.107 in.)
Exhaust 965.0 - 1055.0 N @
28.12 mm
216.9 - 237.1 lbs. @
1.107 in.)
Number of Coils
Intake 7.30
Exhaust 7.45
Wire Diameter
Intake and Exhaust 4.77 ý 3.80mm
(0.1878 - 0.1496 in.)
Installed Height (Spring
Seat to Bottom of
Retainer)
Nominal
Intake 40.12 mm (1.579 in.)
Exhaust 40.12 mm (1.579 in.)
CYLINDER HEAD
Gasket Thickness
(Compressed) 0.7 mm (0.0276 in.)
Valve Seat Angle 44.5É - 45.0É
Valve Seat Runout (MAX) 0.051 mm (0.002 in.)
Valve Seat Width
Intake 1.75 - 2.36 mm
(0.0698 - 0.0928 in.)
Exhaust 1.71 - 2.32 mm
(0.0673 - 0.0911 in.)
Guide Bore Diameter
(Std.)6.975 - 7.00 mm
(0.2747 - 0.2756 in.)
Cylinder Head Warpage
(Flatness) 0.0508 mm (0.002 in.)
OIL PUMP
Clearance Over
Rotors/End Face (MAX)0.095 mm
(0.0038 in.)
9 - 14 ENGINE - 3.7LDR
ENGINE - 3.7L (Continued)

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 (Refer
to 9 - ENGINE - DIAGNOSIS AND TESTING). An
engine cylinder head gasket leaking between adja-
cent cylinders will result in approximately 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.
REMOVAL
(1) Disconnect the negative cable from the battery.
(2) Raise the vehicle on a hoist.
(3) Disconnect the exhaust pipe at the left side
exhaust manifold.
(4) Drain the engine coolant(Refer to 7 - COOL-
ING - STANDARD PROCEDURE).
(5) Lower the vehicle.(6) Remove the intake manifold(Refer to 9 -
ENGINE/MANIFOLDS/INTAKE MANIFOLD -
REMOVAL).
(7) Remove the master cylinder and booster assem-
bly(Refer to 5 - BRAKES/HYDRAULIC/MECHANI-
CAL/POWER BRAKE BOOSTER - REMOVAL).
(8) Remove the cylinder head cover(Refer to 9 -
ENGINE/CYLINDER HEAD/CYLINDER HEAD
COVER(S) - REMOVAL).
(9) Remove the fan shroud and fan blade assem-
bly(Refer to 7 - COOLING/ENGINE/RADIATOR FAN
- REMOVAL).
(10) Remove accessory drive belt(Refer to 7 -
COOLING/ACCESSORY DRIVE/DRIVE BELTS -
REMOVAL).
(11) Remove the power steering pump and set
aside.
(12) Rotate the crankshaft until the damper tim-
ing mark is aligned with TDC indicator mark (Fig.
5).
(13) Verify the V6 mark on the camshaft sprocket
is at the 12 o'clock position (Fig. 6). Rotate the crank-
shaft one turn if necessary.
(14) Remove the crankshaft damper(Refer to 9 -
ENGINE/ENGINE BLOCK/VIBRATION DAMPER -
REMOVAL).
(15) Remove the timing chain cover(Refer to 9 -
ENGINE/VALVE TIMING/TIMING BELT / CHAIN
COVER(S) - REMOVAL).
Fig. 5 Engine Top Dead Center
1 - TIMING CHAIN COVER
2 - CRANKSHAFT TIMING MARKS
DRENGINE - 3.7L 9 - 21
CYLINDER HEAD - LEFT (Continued)

(6) Remove the cylinder head cover mounting bolts
(Fig. 16).
(7) Remove cylinder head cover and gasket.
NOTE: The gasket may be used again, providing no
cuts, tears, or deformation has occurred.
INSTALLATION
CAUTION: Do not use harsh cleaners to clean the
cylinder head covers. Severe damage to covers
may occur.
NOTE: The gasket may be used again, provided no
cuts, tears, or deformation has occurred.
(1) Clean cylinder head cover and both sealing sur-
faces. Inspect and replace gasket as necessary.
(2) Tighten cylinder head cover bolts and double
ended studs to 12 N´m (105 in. lbs.).
(3) Install left side breather and connect breather
tube.
(4) Connect injector electrical connectors and injec-
tor harness retaining clips.(5) Install the resonator and air inlet hose.
(6) Connect negative cable to battery.
INTAKE/EXHAUST VALVES &
SEATS
DESCRIPTION
The valves are made of heat resistant steel and
have chrome plated stems to prevent scuffing. Each
valve is actuated by a roller rocker arm which pivots
on a stationary lash adjuster. All valves use three
bead lock keepers to retain the springs and promote
valve rotation.
STANDARD PROCEDURE - REFACING
NOTE: Valve seats that are worn or burned can be
reworked, provided that correct angle and seat
width are maintained. Otherwise the cylinder head
must be replaced.
NOTE: When refacing valves and valve seats, it is
important that the correct size valve guide pilot be
used for reseating stones. A true and complete sur-
face must be obtained.
(1) Using a suitable dial indicator measure the
center of the valve seat Total run out must not
exceed 0.051 mm (0.002 in).
(2) Apply a small amount of Prussian blue to the
valve seat, insert the valve into the cylinder head,
while applying light pressure on the valve rotate the
valve. Remove the valve and examine the valve face.
If the blue is transferred below the top edge of the
valve face, lower the valve seat using a 15 degree
stone. If the blue is transferred to the bottom edge of
the valve face, raise the valve seat using a 65 degree
stone.
(3) When the seat is properly positioned the width
of the intake seat must be 1.75 ± 2.36 mm (0.0689 ±
0.0928 in.) and the exhaust seat must be 1.71 ± 2.32
mm (0.0673 ± 0.0911 in.).
(4) Check the valve spring installed height after
refacing the valve and seat. The installed height for
both intake and exhaust valve springs must not
exceed 40.74 mm (1.6039 in.).
Fig. 16 CYLINDER HEAD COVER -TYPICAL
1 - SCREWS
2 - CYLINDER HEAD COVER
DRENGINE - 3.7L 9 - 27
CYLINDER HEAD COVER(S) (Continued)

VALVE GUIDE SEALS
DESCRIPTION
The valve guide seals are made of rubber and
incorporate an integral steel valve spring seat. The
integral garter spring maintains consistent lubrica-
tion control to the valve stems.
VALVE SPRINGS
DESCRIPTION
The valve springs are made from high strength
chrome silicon steel. The springs are NOT common
for intake and exhaust applications. The valve spring
seat is integral with the valve stem seal, which is a
positive type seal to control lubrication.
REMOVAL
(1) Remove the cylinder head cover(Refer to 9 -
ENGINE/CYLINDER HEAD/CYLINDER HEAD
COVER(S) - REMOVAL).
(2) Using Special Tool 8516 Valve Spring Compres-
sor, remove the rocker arms and the hydraulic lash
adjusters.
(3) Remove the spark plug for the cylinder the
valve spring and seal are to be removed from.
(4) Apply shop air to the cylinder to hold the
valves in place when the spring is removed.
NOTE: All six valve springs and seals are removed
in the same manner; this procedure only covers
one valve seal and valve spring.
(5) Using Special Tool 8387 Valve Spring Compres-
sor, compress the valve spring.
NOTE: It may be necessary to tap the top of the
valve spring to loosen the spring retainers locks
enough to be removed.
(6) Remove the two spring retainer lock halves.
NOTE: the valve spring is under tension use care
when releasing the valve spring compressor.
(7) Remove the valve spring compressor.
NOTE: The valve springs are NOT common between
intake and exhaust.
(8) Remove the spring retainer, and the spring.
(9) Remove the valve stem seal.
NOTE: The valve stem seals are common between
intake and exhaust.
INSTALLATION
NOTE: All six valve springs and seals are removed
in the same manner; this procedure only covers
one valve seal and valve spring.
(1) Apply shop air to the cylinder to hold the
valves in place while the spring is installed.
NOTE: The valve stem seals are common between
intake and exhaust.
(2) Install the valve stem seal.
NOTE: The valve springs are NOT common between
intake and exhaust.
(3) Install the spring retainer, and the spring.
(4) Using Special Tool 8387 Valve Spring Compres-
sor, compress the valve spring.
(5) Install the two spring retainer lock halves.
NOTE: the valve spring is under tension use care
when releasing the valve spring compressor.
(6) Remove the valve spring compressor.
(7) Disconnect the shop air to the cylinder.
(8) Install the spark plug for the cylinder the valve
spring and seal was installed on.
(9) Using Special Tool 8516 Valve Spring Compres-
sor, install the rocker arms and the hydraulic lash
adjusters.
(10) Install the cylinder head cover(Refer to 9 -
ENGINE/CYLINDER HEAD/CYLINDER HEAD
COVER(S) - INSTALLATION).
CYLINDER HEAD - RIGHT
DIAGNOSIS AND TESTING - HYDRAULIC LASH
ADJUSTER
A tappet-like noise may be produced from several
items. Check the following items.
(1) Engine oil level too high or too low. This may
cause aerated oil to enter the adjusters and cause
them to be spongy.
(2) Insufficient running time after rebuilding cylin-
der head. Low speed running up to 1 hour may be
required.
(3) Turn engine off and let set for a few minutes
before restarting. Repeat this several times after
engine has reached normal operating temperature.
(4) Low oil pressure.
(5) The oil restrictor in cylinder head gasket or the
oil passage to the cylinder head is plugged with
debris.
DRENGINE - 3.7L 9 - 31

(12) Remove cylinder head cover retaining bolts.
(13) Remove cylinder head cover.
INSTALLATION
CAUTION: Do not use harsh cleaners to clean the
cylinder head covers. Severe damage to covers
may occur.
NOTE: The gasket may be used again, provided no
cuts, tears, or deformation has occurred.
(1) Clean cylinder head cover and both sealing sur-
faces. Inspect and replace gasket as necessary.
(2) Tighten cylinder head cover bolts and double
ended studs to 12 N´m (105 in. lbs).
(3) Install right rear breather tube and filter
assembly.
(4) Connect injector, ignition coil electrical connec-
tors and harness retaining clips.
(5) Install the oil fill tube.
(6) Install PCV hose.
(7) Install heater hoses.
(8) Install air conditioning compressor retaining
bolts.
(9) Install accessory drive belt(Refer to 7 - COOL-
ING/ACCESSORY DRIVE/DRIVE BELTS - INSTAL-
LATION).
(10) Fill Cooling system(Refer to 7 - COOLING -
STANDARD PROCEDURE).
(11) Install air cleaner assembly, resonator assem-
bly and air inlet hose.
(12) Connect battery negative cable.
ROCKER ARM
DESCRIPTION
The rocker arms are steel stampings with an inte-
gral roller bearing. The rocker arms incorporate a 2.8
mm (0.11 inch) oil hole in the lash adjuster socket for
roller and camshaft lubrication.
REMOVAL
NOTE: Disconnect the battery negative cable to pre-
vent accidental starter engagement.
(1) Remove the cylinder head cover (Refer to 9 -
ENGINE/CYLINDER HEAD/CYLINDER HEAD
COVER(S) - REMOVAL).
(2) For rocker arm removal on cylinder #4, Rotate
the crankshaft until cylinder #1 is at BDC intake
stroke.(3) For rocker arm removal on cylinder #1, Rotate
the crankshaft until cylinder #1 is at BDC combus-
tion stroke.
(4) For rocker arm removal on cylinders #3 and #5,
Rotate the crankshaft until cylinder #1 is at TDC
exhaust stroke.
(5) For rocker arm removal on cylinders #2 and #6,
Rotate the crankshaft until cylinder #1 is at TDC
ignition stroke.
(6) Using special tool 8516 Rocker Arm Remover,
press downward on the valve spring, remove rocker
arm (Fig. 28).
VALVE GUIDE SEALS
DESCRIPTION
The valve guide seals are made of rubber and
incorporate an integral steel valve spring seat. The
integral garter spring maintains consistent lubrica-
tion control to the valve stems.
VALVE SPRINGS
DESCRIPTION
The valve springs are made from high strength
chrome silicon steel. There are different springs for
intake and exhaust applications. The valve spring
seat is integral with the valve stem seal, which is a
positive type seal to control lubrication.
Fig. 28 Rocker Arm - Removal
1 - CAMSHAFT
2 - SPECIAL TOOL 8516
9 - 36 ENGINE - 3.7LDR
CYLINDER HEAD COVER(S) (Continued)

REMOVAL
(1) Remove the cylinder head cover(Refer to 9 -
ENGINE/CYLINDER HEAD/CYLINDER HEAD
COVER(S) - REMOVAL).
(2) Using Special Tool 8516 Valve Spring Compres-
sor, remove the rocker arms and the hydraulic lash
adjusters.
(3) Remove the spark plug for the cylinder the
valve spring and seal are to be removed from.
(4) Apply shop air to the cylinder to hold the
valves in place when the spring is removed.
NOTE: All six valve springs and seals are removed
in the same manner; this procedure only covers
one valve seal and valve spring.
(5) Using Special Tool 8387 Valve Spring Compres-
sor, compress the valve spring.
NOTE: It may be necessary to tap the top of the
valve spring to loosen the spring retainers locks
enough to be removed.
(6) Remove the two spring retainer lock halves.
NOTE: the valve spring is under tension use care
when releasing the valve spring compressor.
(7) Remove the valve spring compressor.
NOTE: The valve springs are NOT common between
intake and exhaust.
(8) Remove the spring retainer, and the spring.
(9) Remove the valve stem seal.
NOTE: The valve stem seals are common between
intake and exhaust.
INSTALLATION
NOTE: All six valve springs and seals are removed
in the same manner; this procedure only covers
one valve seal and valve spring.
(1) Apply shop air to the cylinder to hold the
valves in place while the spring is installed.
NOTE: The valve stem seals are common between
intake and exhaust.
(2) Install the valve stem seal.NOTE: The valve springs are NOT common between
intake and exhaust.
(3) Install the spring retainer, and the spring.
(4) Using Special Tool 8387 Valve Spring Compres-
sor, compress the valve spring.
(5) Install the two spring retainer lock halves.
NOTE: the valve spring is under tension use care
when releasing the valve spring compressor.
(6) Remove the valve spring compressor.
(7) Disconnect the shop air to the cylinder.
(8) Install the spark plug for the cylinder the valve
spring and seal was installed on.
(9) Using Special Tool 8516 Valve Spring Compres-
sor, install the rocker arms and the hydraulic lash
adjusters.
(10) Install the cylinder head cover(Refer to 9 -
ENGINE/CYLINDER HEAD/CYLINDER HEAD
COVER(S) - INSTALLATION).
ENGINE BLOCK
DESCRIPTION
The cylinder block is made of cast iron. The block
is a closed deck design with the left bank forward. To
provide high rigidity and improved NVH an
enhanced compacted graphite bedplate is bolted to
the block. The block design allows coolant flow
between the cylinders bores, and an internal coolant
bypass to a single poppet inlet thermostat is included
in the cast aluminum front cover.
STANDARD PROCEDUREÐCYLINDER BORE
HONING
Before honing, stuff plenty of clean shop towels
under the bores and over the crankshaft to keep
abrasive materials from entering the crankshaft
area.
(1) Used carefully, the Cylinder Bore Sizing Hone
C-823, equipped with 220 grit stones, is the best tool
for this job. In addition to deglazing, it will reduce
taper and out-of-round, as well as removing light
scuffing, scoring and scratches. Usually, a few strokes
will clean up a bore and maintain the required lim-
its.
CAUTION: DO NOT use rigid type hones to remove
cylinder wall glaze.
DRENGINE - 3.7L 9 - 37
VALVE SPRINGS (Continued)

(2) Deglazing of the cylinder walls may be done if
the cylinder bore is straight and round. Use a cylin-
der surfacing hone, Honing Tool C-3501, equipped
with 280 grit stones (C-3501-3810). about 20-60
strokes, depending on the bore condition, will be suf-
ficient to provide a satisfactory surface. Using honing
oil C-3501-3880, or a light honing oil, available from
major oil distributors.
CAUTION: DO NOT use engine or transmission oil,
mineral spirits, or kerosene.
(3) Honing should be done by moving the hone up
and down fast enough to get a crosshatch pattern.
The hone marks should INTERSECT at 50É to 60É
for proper seating of rings (Fig. 29).
(4) A controlled hone motor speed between 200 and
300 RPM is necessary to obtain the proper cross-
hatch angle. The number of up and down strokes per
minute can be regulated to get the desired 50É to 60É
angle. Faster up and down strokes increase the cross-
hatch angle.
(5) After honing, it is necessary that the block be
cleaned to remove all traces of abrasive. Use a brush
to wash parts with a solution of hot water and deter-
gent. Dry parts thoroughly. Use a clean, white, lint-
free cloth to check that the bore is clean. Oil the
bores after cleaning to prevent rusting.CLEANING
Thoroughly clean the oil pan and engine block gas-
ket surfaces.
Use compressed air to clean out:
²The galley at the oil filter adaptor hole.
²The front and rear oil galley holes.
²The feed holes for the crankshaft main bearings.
Once the block has been completely cleaned, apply
Loctite PST pipe sealant with Teflon 592 to the
threads of the front and rear oil galley plugs. Tighten
the 1/4 inch NPT plugs to 20 N´m (177 in. lbs.)
torque. Tighten the 3/8 inch NPT plugs to 27 N´m
(240 in. lbs.) torque.
INSPECTION
(1) It is mandatory to use a dial bore gauge to
measure each cylinder bore diameter. To correctly
select the proper size piston, a cylinder bore gauge,
capable of reading in 0.003 mm (.0001 in.) INCRE-
MENTS is required. If a bore gauge is not available,
do not use an inside micrometer (Fig. 30).
(2) Measure the inside diameter of the cylinder
bore at three levels below top of bore. Start perpen-
dicular (across or at 90 degrees) to the axis of the
crankshaft and then take two additional reading.
(3) Measure the cylinder bore diameter crosswise
to the cylinder block near the top of the bore. Repeat
the measurement near the middle of the bore, then
repeat the measurement near the bottom of the bore.
Fig. 29 CYLINDER BORE CROSSHATCH PATTERN
1 - CROSSHATCH PATTERN
2 - INTERSECT ANGLE
Fig. 30 BORE GAUGE-TYPICAL
1 - FRONT
2 - BORE GAUGE
3 - CYLINDER BORE
4 - 38 MM (1.5 in)
9 - 38 ENGINE - 3.7LDR
ENGINE BLOCK (Continued)

INSTALLATION
CAUTION: Main bearings are select fit. Refer to
Crankshaft Main Bearings in this section for proper
bearing selections.
CAUTION: When installing crankshaft, use care not
to damage bearing surfaces on the crankshaft.
NOTE: Apply sealant to the tone wheel retaining
screws prior to installation.
(1) Lubricate upper main bearing halves with
clean engine oil.
(2) Install the crankshaft tone wheel. Torque the
mounting screws to 15 N´m (11 ft. lbs.).
(3) Position crankshaft in cylinder block.
(4) Install the thrust washers (Fig. 33).
CAUTION: The bedplate to cylinder block mating
surface must be coated with MoparTEngine RTV
sealant prior to installation. Failure to do so will
cause severe oil leaks.NOTE: Make sure that the bedplate and cylinder
block sealing surfaces are clean and free of oil or
other contaminants. Contaminants on the sealing
surfaces may cause main bearing distortion and/or
oil leaks.
(5) Apply a 2.5mm (0.100 inch) bead of Mopart
Engine RTV sealant to the cylinder block-to-bedplate
mating surface as shown (Fig. 34).
(6) Coat the crankshaft main bearing journals
with clean engine oil and position the bedplate onto
the cylinder block.
NOTE: Lubricate the bedplate retaining bolts with
clean engine oil prior to installation.
Fig. 33 Crankshaft Thrust Washer Installation
1 - CRANKSHAFT THRUST WASHER
Fig. 34 BEDPLATE SEALANT
1 - CYLINDER BLOCK
2 - SEALENT
3 - SEALANT
DRENGINE - 3.7L 9 - 41
CRANKSHAFT (Continued)