1998 DODGE RAM 1500 Camshaft

(12) Disconnect heater hoses from heater core and
remove hose assembly.
(13) Disconnect throttle and speed control cables.
(14) Remove upper radiator hose from engine.
(15) Remove lower radiator hose from engine.
(16) Remove radiator/cooling module assembly.
(17) Disconnect the engine to body ground straps
at the left side of cowl.
(18) Disconnect the engine wiring harness at the
following points:
²Intake air temperature (IAT) sensor
²Fuel Injectors
²Throttle Position (TPS) Switch
²Idle Air Control (IAC) Motor
²Engine Oil Pressure Switch
²Engine Coolant Temperature (ECT) Sensor
²Manifold Absolute Pressure MAP) Sensor
²Camshaft Position (CMP) Sensor
²Coil Over Plugs
²Crankshaft Position Sensor
(19) Remove coil over plugs.
(20) Release fuel rail pressure.
(21) Remove fuel rail and secure away from
engine.
NOTE: It is not necessary to release the quick con-
nect fitting from the fuel supply line for engine
removal.
(22) Remove the PCV hose.
(23) Remove the breather hoses.
(24) Remove the vacuum hose for the power brake
booster.
(25) Disconnect knock sensors.
(26) Remove engine oil dipstick tube.
(27) Remove intake manifold.
(28) Install engine lifting fixture,special tool#8247,
using original fasteners from the removed intake
manifold, and fuel rail. Torque to factory specifica-
tions.
NOTE: Recheck bolt torque for engine lift plate
before removing engine.
(29) Secure the left and right engine wiring har-
nesses away from engine.
(30) Raise vehicle.
(31) Disconnect oxygen sensor wiring.
(32) Disconnect crankshaft postion sensor.
(33) Disconnect the engine block heater power
cable, if equipped.
(34) Disconnect the front propshaft at the front
differential and secure out of way.
NOTE: It is necessary to disconnect the front prop-
shaft for access to the starter and left side exhaust
flange.(35) Remove the starter.
(36) Remove the ground straps from the left and
right side of the block.
(37) Disconnect the right and left exhaust pipes at
the manifolds and from the crossover, and remove
from the vehicle.
NOTE: The exhaust clamps at the manifolds cannot
be reused. New clamps must be used or leaks may
occur.
(38) Remove the structural cover.
(39) Remove torque convertor bolts, and mark
location for reassembly.
(40) Remove transmission bellhousing to engine
bolts.
(41) Remove left and right engine mount thru
bolts.
(42) Lower the vehicle.
(43) Support the transmission with a suitable jack.
(44) Connect a suitable engine hoist to the engine
lift plate.
(45) Remove engine from vehicle.
INSTALLATION
(1) Position the engine in the vehicle.
(2) Install both left and right side engine mounts
onto engine.
(3) Raise the vehicle.
(4) Install the transmission bellhousing to engine
mounting bolts. Tighten the bolts to 41 N´m (30ft.
lbs.).
(5) Tighten the engine mount thru bolts.
(6) Install the torque convertor bolts.
(7) Connect the ground straps on the left and right
side of the engine.
(8) Install the starter.
(9) Connect the crankshaft position sensor.
(10) Install the engine block heater power cable, if
equipped.
CAUTION: The structural cover requires a specific
torque sequence. Failure to follow this sequence
may cause severe damage to the cover.
(11) Install the structural cover.
NOTE: New clamps must be used on exhaust man-
ifold flanges. Failure to use new clamps may result
in exhaust leaks.
(12) Install the left and right exhaust pipes.
(13) Connect the left and right oxygen sensors.
(14) Lower vehicle.
(15) Remove the engine lift plate.
(16) Connect the knock sensors.
DRENGINE - 3.7L 9 - 11
ENGINE - 3.7L (Continued)

(17) Connect the engine to body ground straps at
the left side of the cowl.
(18) Install the intake manifold.
(19) Install the engine oil dipstick tube.
(20) Install the power brake booster vacuum hose.
(21) Install the breather hoses.
(22) Install the PCV hose.
(23) Install the fuel rail.
(24) Install the coil over plugs.
(25) Connect the engine wiring harness at the fol-
lowing points:
²Intake air temperature (IAT) sensor
²Fuel Injectors
²Throttle Position (TPS) Switch
²Idle Air Control (IAC) Motor
²Engine Oil Pressure Switch
²Engine Coolant Temperature (ECT) Sensor
²Manifold Absolute Pressure MAP) Sensor
²Camshaft Position (CMP) Sensor
²Coil Over Plugs
²Crankshaft Position Sensor
(26) Reinstall the radiator/cooling module assem-
bly.
(27) Connect lower radiator hose.
(28) Connect upper radiator hose.
(29) Connect throttle and speed control cables.
(30) Install the heater hose assembly.
(31) Install coolant recovery bottle.
(32) Install the power steering pump.
(33) Install the generator.
(34) Install the A/C compressor.
(35) Install the drive belt.
(36) Install the fan shroud with the viscous fan
assembly.
(37) Install the radiator core support bracket.
(38) Install the air cleaner assembly.
(39) Refill the engine cooling system.
(40) Recharge the air conditioning.
(41) Install the hood.
(42) Check and fill engine oil.
(43) Connect the battery negative cable.
(44) Start the engine and check for leaks.SPECIFICATIONS
SPECIFICATIONS - 3.7L ENGINE
GENERAL SPECIFICATIONS
DESCRIPTION SPECIFICATION
Type 90É SOHC V6 12 Valve
Number of
Cylinders4
Firing Order 1-6-5-4-3-2
Lead Cylinder No. 1 Left Bank
Compression
Ratio9.1:1
Max. Variation
Between
Cylinders25%
Metric Standard
Displacement 3.7 Liters 226 Cubic
Inches
Bore 93.0 mm 3.66 in.
Stroke 90.8 mm 3.40 in.
Horsepower 210@5200 RPM
Torque 225ft. lbs.@4200 PRM
Compression
Pressure1172-1551 kPa 170-225 psi
CYLINDER BLOCK
DESCRIPTION SPECIFICATION
Metric Standard
Bore Diameter 93.0   .0075
mm3.6619   0.0003
in.
Out of Round
(MAX)0.076 mm 0.003 in.
Taper (MAX) 0.051 mm 0.002 in.
9 - 12 ENGINE - 3.7LDR
ENGINE - 3.7L (Continued)

CRANKSHAFT
DESCRIPTION SPECIFICATION
Metric Standard
Main Bearing
Journal
Diameter63.488 - 63.512
mm2.4996 - 2.5005
in.
Bearing
Clearance0.002 - 0.034
mm-
Out of Round
(MAX)0.005 mm 0.0002 in.
Taper (MAX) 0.006 mm 0.0004 in.
End Play 0.052 - 0.282
mm0.0021 - 0.0112
in.
End Play (MAX) 0.282 mm 0.0112 in.
Connecting Rod
Journal
Diameter57.908 - 57.892
mm-
Bearing
Clearance0.015 - 0.055 -
Out of Round
(MAX)0.005 mm 0.0002 in.
Taper (MAX) 0.006 mm 0.0002 in.
CAMSHAFT
DESCRIPTION SPECIFICATION
Metric Standard
Bore Diameter 26.02 - 26.04
mm1.0245 - 1.0252
in.
Bearing Journal
Diameter25.975 - 25.995
mm1.0227 - 1.0235
in.
Bearing
Clearance0.025 - 0.065
mm0.001 - 0.0026
in.
Bearing
Clearance
(MAX)0.065 mm 0.0026 in.
End Play .075 - .200 mm 0.003 - 0.0079
in.
End Play (MAX) .200 mm 0.0079 in.
VALVE TIMING
DESCRIPTION SPECIFICATION
Intake
Opens (ATDC) 0.0É
Closes (ATDC) 236É
Duration 236É
Exhaust
Opens (BTDC) 233É
Closes (ATDC) 17É
Duration 250É
Valve Overlap 17É
VALVES
DESCRIPTION SPECIFICATION
Metric Standard
Face Angle 45É - 45.5É
Head Diameter
Intake 48.52 - 48.78
mm1.9103 - 1.9205
in.
Exhaust 36.87 - 37.13
mm1.4516 - 1.4618
in.
Length (Overall)
Intake 113.45 - 114.21
mm4.4666 - 4.4965
in.
Exhaust 114.92 - 115.68
mm4.5244 - 4.5543
in.
Stem Diameter
Intake 6.931 - 6.957
mm0.2729 - 0.2739
in.
Exhaust 6.902 - 6.928
mm0.2717 - 0.2728
in.
Stem-to-Guide
Clearance
Intake 0.018 - 0.069
mm0.0008 - 0.0028
in.
Exhaust 0.047 - 0.098
mm0.0019 - 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.
9 - 14 ENGINE - 3.7LDR
ENGINE - 3.7L (Continued)

OIL PRESSURE
SPECIFICATION SPECIFICATION
Metric Standard
At Curb Idle
Speed (MIN)*25 kPa 4 psi
@ 3000 rpm 170 - 758 kPa 25 - 110 psi
* CAUTION: If pressure is zero at curb idle, DO
NOT run engine at 3000 rpm.
TORQUE
DESCRIPTION N´m Ft.
Lbs.In.
Lbs.
Camshaft
Non - Oiled Sprocket Bolt 122 90 -
Bearing Cap Bolts 11 - 100
Counterbalance shaft
retaining bolt28 - 250
Timing Chain Cover-Bolts 58 43 -
Connecting Rod Cap-Bolts 27 20 -
PLUS 90É TURN
Bed Plate-Bolts Refer to Procedure
Crankshaft Damper-Bolt 175 130 -
Cylinder Head-Bolts
M11 Bolts Refer To Procedure
M8 Bolts Refer To Procedure
Cylinder Head Cover-Bolts 12 - 105
Exhaust Manifold-Bolts 25 18 -
Exhaust Manifold Heat
Shield-Nuts8-72
Then loosen 45É
DESCRIPTION N´m Ft.
Lbs.In.
Lbs.
Flexplate-Bolts 95 70 -
Engine Mount Bracket to
Block-Bolts61 45 -
Rear Mount to Transmission-
Bolts46 34 -
Generator Mounting-Bolts
M10 Bolts 54 40 -
M8 Bolts 28 - 250
Intake Manifold-Bolts 12 - 105
Refer to Procedure
for Tightening
Sequence
Oil Pan-Bolts 15 - 130
Oil Pan-Drain Plug 34 25 -
Oil Pump-Bolts 28 - 250
Oil Pump Cover-Bolts 12 - 105
Oil Pickup Tube-Bolt and Nut 28 - 250
Oil Dipstick Tube to Engine
Block-Bolt15 - 130
Oil Fill Tube-Bolts 12 - 105
Timing Chain Guide-Bolts 28 - 250
Timing Chain Tensioner Arm 28 - 250
Hydraulic Tensioner-Bolts 28 - 250
Timing Chain Primary
Tensioner-Bolts28 - 250
Timing Drive Idler Sprocket-
Bolt34 25 -
Thermostat Housing-Bolts 12 - 105
Water Pump-Bolts 58 43 -
9 - 16 ENGINE - 3.7LDR
ENGINE - 3.7L (Continued)

Crankshaft Damper Installer 8512
Puller 1026
Crankshaft Damper Removal Insert 8513
Chain Tensioner Wedge 8379
Chain Tensioner Pins 8514
VALVE SPRING COMPRESSOR 8426
ENGINE LIFTING FIXTURE 8427
CAMSHAFT HOLDER 8428
9 - 18 ENGINE - 3.7LDR
ENGINE - 3.7L (Continued)

HOLDER SECONDARY CAMSHAFT CHAIN 8429
Remover, Rocker Arm 8516
Idler Shaft Remover 8517
Valve Spring Compressor Adapters 8519
INSTALLER - REMOVER - COUNTER BALANCE
SHAFT 8641
Valve Spring Tester C-647
Dial Indicator C-3339
Valve Spring Compressor C-3422-B
DRENGINE - 3.7L 9 - 19
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
9 - 22 ENGINE - 3.7LDR
CYLINDER HEAD - LEFT (Continued)

(16) Lock the secondary timing chains to the idler
sprocket using Special Tool 8429 Timing Chain Hold-
ing Fixture (Fig. 7).NOTE: Mark the secondary timing chain prior to
removal to aid in installation.
(17) Mark the secondary timing chain, one link on
each side of the V6 mark on the camshaft drive gear.
(18) Remove the left side secondary chain ten-
sioner. Refer to Timing Chain and Sprockets.
(19) Remove the cylinder head access plug (Fig. 8).
Fig. 6 CAMSHAFT SPROCKET V6 MARKS (#1 TDC, Exhaust stroke)
1 - LEFT CYLINDER HEAD2 - RIGHT CYLINDER HEAD
Fig. 7 Using Special Tool 8429
1 - SPECIAL TOOL 8429
2 - CAMSHAFT CHAIN
3 - CRANKSHAFT TIMING GEAR
Fig. 8 Cylinder Head Access Plugs
1 - RIGHT CYLINDER HEAD ACCESS PLUG
2 - LEFT CYLINDER HEAD ACCESS PLUG
DRENGINE - 3.7L 9 - 23
CYLINDER HEAD - LEFT (Continued)