1998 DODGE RAM 1500 5.9l

(5) Before starting engine, operate accelerator
pedal to check for any binding.
(6) Install cable/lever cover.
SERVO
DESCRIPTION
A speed control servo is not used with any
5.7L V-8 engine, or with the 5.9L diesel engine
when equipped with a manual transmission.
The speed control servo is attached to the bottom
of the battery tray.
The servo unit consists of a solenoid valve body,
and a vacuum chamber. The solenoid valve body con-
tains three solenoids:
²Vacuum
²Vent
²Dump
The vacuum chamber contains a diaphragm with a
cable attached to control the throttle linkage.
OPERATION
A speed control servo is not used with any
5.7L V-8 engine, or with the 5.9L diesel engine
when equipped with a manual transmission.
The following information applies only to
vehicles equipped with a mechanical servo.
When/if a servo is used on gasoline powered vehi-
cles, the Powertrain Control Module (PCM) controls
the solenoid valve body. When/if a servo is used on
certain diesel powered vehicles, the Engine Control
Module (ECM) controls the solenoid valve body. The
solenoid valve body controls the application and
release of vacuum to the diaphragm of the vacuum
servo. The servo unit cannot be repaired and is ser-
viced only as a complete assembly.
Power is supplied to the servo's by the PCM/ECM
through the brake switch. The PCM/ECM controls
the ground path for the vacuum and vent solenoids.
The dump solenoid is energized anytime it receives
power. If power to the dump solenoid is interrupted,
the solenoid dumps vacuum in the servo. This pro-
vides a safety backup to the vent and vacuum sole-
noids.
The vacuum and vent solenoids must be grounded
at the PCM/ECM to operate. When the PCM/ECM
grounds the vacuum servo solenoid, the solenoid
allows vacuum to enter the servo and pull open the
throttle plate using the cable. When the PCM/ECM
breaks the ground, the solenoid closes and no more
vacuum is allowed to enter the servo. The PCM/ECM
also operates the vent solenoid via ground. The vent
solenoid opens and closes a passage to bleed or hold
vacuum in the servo as required.The PCM/ECM duty cycles the vacuum and vent
solenoids to maintain the set speed, or to accelerate
and decelerate the vehicle. To increase throttle open-
ing, the PCM/ECM grounds the vacuum and vent
solenoids. To decrease throttle opening, the PCM/
ECM removes the grounds from the vacuum and
vent solenoids. When the brake is released, if vehicle
speed exceeds 30 mph to resume, 35 mph to set, and
the RES/ACCEL switch has been depressed, ground
for the vent and vacuum circuits is restored.
REMOVAL
The speed control servo assembly is attached to the
bottom of the battery tray (Fig. 6).
(1) Disconnect negative battery cable at battery
(both cables at both batteries if diesel).
(2) To gain access to servo, remove plastic wheel-
house splash shield over left-front wheel.
(3) Disconnect vacuum line at servo (Fig. 6).
(4) Disconnect electrical connector at servo (Fig. 6).
(5) Remove 3 servo mounting screws (Fig. 6).
Depending on engine application, different sets of
mounting lugs (Fig. 6) are used to support servo to
battery tray. While removing, note proper lugs.
(6) Disconnect servo cable at throttle body. Refer to
Servo Cable Removal/Installation.
(7) Remove 2 mounting nuts holding servo cable
sleeve to bracket (Fig. 7).
(8) Pull speed control cable sleeve and servo away
from servo mounting bracket to expose cable retain-
ing clip (Fig. 7) and remove clip. Note: The servo
mounting bracket displayed in (Fig. 7) is a typical
bracket and may/may not be applicable to this model
vehicle.
(9) Remove servo from mounting bracket. While
removing, note orientation of servo to bracket.
INSTALLATION
(1) Position servo to mounting bracket (Fig. 7).
(2) Align hole in cable connector with hole in servo
pin. Install cable-to-servo retaining clip (Fig. 7).
(3) Insert servo mounting studs through holes in
servo mounting bracket.
(4) Install 2 servo-to-mounting bracket nuts and
tighten. Refer to torque specifications.
(5) Position servo assembly to correct mounting
lugs on battery tray (Fig. 6) and install 3 screws.
Tighten 3 screws. Refer to torque specifications.
(6) Connect vacuum line at servo.
(7) Connect electrical connector at servo.
(8) Connect servo cable to throttle body. Refer to
servo Cable Removal/Installation.
(9) Install left-front wheel-well liner.
(10) Connect negative battery cable to battery
(connect both cables if diesel).
8P - 6 SPEED CONTROLDR
CABLE (Continued)

ENGINE
TABLE OF CONTENTS
page page
ENGINE - 3.7L............................ 1
ENGINE - 4.7L........................... 88ENGINE - 5.7L.......................... 180
ENGINE 5.9L DIESEL..................... 230
ENGINE - 3.7L
TABLE OF CONTENTS
page page
ENGINE - 3.7L
DESCRIPTION..........................3
DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTING - ENGINE
DIAGNOSIS - INTRODUCTION............4
DIAGNOSIS AND TESTING - ENGINE
DIAGNOSIS - PERFORMANCE............4
DIAGNOSIS AND TESTING - ENGINE
DIAGNOSIS - MECHANICAL..............6
DIAGNOSIS AND TESTING - ENGINE
DIAGNOSIS - LUBRICATION..............7
DIAGNOSIS AND TESTING - CYLINDER
COMPRESSION PRESSURE..............8
DIAGNOSIS AND TESTING - CYLINDER
COMBUSTION PRESSURE LEAKAGE.......8
STANDARD PROCEDURE
STANDARD PROCEDURE - REPAIR
DAMAGED OR WORN THREADS..........9
STANDARD PROCEDURE - FORM-IN-
PLACE GASKETS AND SEALERS..........9
STANDARD PROCEDURE - ENGINE
GASKET SURFACE PREPARATION........10
REMOVAL.............................10
INSTALLATION.........................11
SPECIFICATIONS
SPECIFICATIONS - 3.7L ENGINE.........12
TORQUE............................16
SPECIAL TOOLS.......................17
AIR CLEANER ELEMENT
REMOVAL.............................21
INSTALLATION.........................21
CYLINDER HEAD - LEFT
DIAGNOSIS AND TESTING - CYLINDER HEAD
GASKET............................21
REMOVAL.............................22
INSTALLATION.........................24
CAMSHAFT(S)
DESCRIPTION.........................25
REMOVAL.............................25INSTALLATION.........................27
CYLINDER HEAD COVER(S)
DESCRIPTION.........................27
REMOVAL.............................28
INSTALLATION.........................28
INTAKE/EXHAUST VALVES & SEATS
DESCRIPTION.........................28
STANDARD PROCEDURE - REFACING......28
REMOVAL.............................29
INSTALLATION.........................30
ROCKER ARM
DESCRIPTION.........................31
REMOVAL.............................31
INSTALLATION.........................31
VALVE GUIDE SEALS
DESCRIPTION.........................32
VALVE SPRINGS
DESCRIPTION.........................32
REMOVAL.............................32
INSTALLATION.........................32
CYLINDER HEAD - RIGHT
DIAGNOSIS AND TESTING - HYDRAULIC
LASH ADJUSTER.....................32
REMOVAL.............................33
INSTALLATION.........................34
CAMSHAFT(S)
DESCRIPTION.........................35
REMOVAL.............................35
INSTALLATION.........................36
CYLINDER HEAD COVER(S)
REMOVAL.............................37
INSTALLATION.........................37
ROCKER ARM
DESCRIPTION.........................37
REMOVAL.............................37
VALVE GUIDE SEALS
DESCRIPTION.........................38
VALVE SPRINGS
DESCRIPTION.........................38
DRENGINE 9 - 1

ENGINE 5.9L DIESEL
TABLE OF CONTENTS
page page
ENGINE 5.9L DIESEL
DESCRIPTION........................232
DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTINGÐENGINE
DIAGNOSIS - MECHANICAL............233
DIAGNOSIS AND TESTINGÐSMOKE
DIAGNOSIS CHARTS.................236
DIAGNOSIS AND TESTING - CYLINDER
COMPRESSION/LEAKAGE TESTS.......239
STANDARD PROCEDURE
STANDARD PROCEDURE - FORM-IN-
PLACE GASKETS AND SEALERS........239
STANDARD PROCEDURE - REPAIR
DAMAGED OR WORN THREADS........240
STANDARD PROCEDUREÐHYDROSTATIC
LOCK..............................240
REMOVAL
REMOVAL - ENGINE..................241
REMOVALÐCRANKCASE BREATHER....242
INSTALLATION
INSTALLATION - ENGINE..............242
INSTALLATIONÐCRANKCASE BREATHER . 243
SPECIFICATIONS
SPECIFICATIONS - 5.9L DIESEL.........244
TORQUE...........................245
SPECIAL TOOLS
5.9L DIESEL ENGINE.................246
ENGINE DATA PLATE
DESCRIPTION........................248
AIR CLEANER ELEMENT
REMOVAL............................248
INSTALLATION........................249
CYLINDER HEAD
DESCRIPTION........................249
REMOVAL............................249
CLEANING
CLEANINGÐCYLINDER HEAD..........251
CLEANINGÐCROSSHEADS............251
CLEANINGÐPUSHRODS..............252
INSPECTION
INSPECTION - CYLINDER HEAD.........252
INSPECTIONÐCROSSHEADS..........252
INSPECTIONÐPUSHRODS.............253
INSTALLATION........................253
CYLINDER HEAD COVER(S)
REMOVAL
REMOVALÐCYLINDER HEAD COVER....255
REMOVALÐROCKER HOUSING.........255
CLEANING...........................255INSPECTION.........................255
INSTALLATION
INSTALLATIONÐCYLINDER HEAD COVER . 255
INSTALLATION - ROCKER HOUSING.....255
INTAKE/EXHAUST VALVES & SEATS
DESCRIPTION........................256
STANDARD PROCEDURE
STANDARD PROCEDURE - VALVES,
GUIDES AND SPRINGS................256
STANDARD PROCEDURE - VALVE LASH
ADJUSTMENT AND VERIFICATION.......259
REMOVAL - VALVE SPRINGS AND SEALS . . . 260
INSTALLATION........................261
ROCKER ARM / ADJUSTER ASSY
DESCRIPTION........................261
REMOVAL............................261
CLEANING...........................262
INSPECTION.........................262
INSTALLATION........................263
ENGINE BLOCK
STANDARD PROCEDURE
STANDARD PROCEDURE - CYLINDER
BLOCK REFACING...................264
STANDARD PROCEDURE - CYLINDER
BORE - DE-GLAZE...................264
STANDARD PROCEDUREÐCYLINDER
BORE REPAIR.......................265
STANDARD PROCEDUREÐCAM BORE
REPAIR ............................267
INSPECTION.........................267
CAMSHAFT & BEARINGS (IN BLOCK)
REMOVAL
REMOVALÐCAMSHAFT BEARINGS......268
REMOVAL - CAMSHAFT...............268
INSPECTION.........................270
INSTALLATION
INSTALLATION - CAMSHAFT BEARINGS . . 271
INSTALLATION - CAMSHAFT............271
CONNECTING ROD BEARINGS
STANDARD PROCEDURE - CONNECTING
ROD BEARING AND CRANKSHAFT
JOURNAL CLEARANCE................272
CRANKSHAFT AND GEAR
DESCRIPTION........................273
REMOVAL - GEAR.....................273
INSTALLATION - GEAR..................273
CRANKSHAFT MAIN BEARINGS
STANDARD PROCEDURE - MAIN BEARING
CLEARANCE........................274
9 - 230 ENGINE 5.9L DIESELDR

CRANKSHAFT OIL SEAL - FRONT
REMOVAL............................275
INSTALLATION........................275
CRANKSHAFT OIL SEAL - REAR
REMOVAL............................276
INSTALLATION........................276
CRANKSHAFT REAR OIL SEAL RETAINER
REMOVAL............................277
INSTALLATION........................277
SOLID LIFTERS/TAPPETS
REMOVAL............................279
CLEANING...........................279
INSPECTION.........................279
INSTALLATION........................280
PISTON & CONNECTING ROD
DESCRIPTION........................281
STANDARD PROCEDURE - HEAD GASKET
SELECTION.........................281
REMOVAL............................281
CLEANINGÐPISTON AND CONNECTING
ROD ..............................282
INSPECTION
INSPECTION - PISTONS...............282
INSPECTIONÐCONNECTING ROD.......283
INSTALLATION........................283
PISTON RINGS
STANDARD PROCEDURE - PISTON RING
FITTING............................284
VIBRATION DAMPER
REMOVAL............................285
INSPECTION.........................285
INSTALLATION........................286
FRONT MOUNT
REMOVAL............................286
INSTALLATION........................287
REAR MOUNT
REMOVAL............................288
INSTALLATION........................288
LUBRICATION
DESCRIPTION........................289
OPERATION..........................289
DIAGNOSIS AND TESTINGÐENGINE OIL
PRESSURE.........................289
OIL
STANDARD PROCEDURE
STANDARD PROCEDURE - ENGINE OIL
LEVEL.............................292STANDARD PROCEDURE - ENGINE OIL
SERVICE...........................292
OIL COOLER & LINES
CLEANING
CLEANING AND INSPECTION...........293
OIL FILTER
REMOVAL............................293
INSTALLATION........................293
OIL PAN
REMOVAL............................293
CLEANING...........................293
INSPECTION.........................293
INSTALLATION........................293
OIL PRESSURE RELIEF VALVE
REMOVAL............................294
CLEANING...........................294
INSPECTION.........................294
INSTALLATION........................294
OIL PRESSURE SWITCH
REMOVAL............................294
INSTALLATION........................294
OIL PUMP
REMOVAL............................294
CLEANING...........................295
INSPECTION.........................295
INSTALLATION........................296
INTAKE MANIFOLD
REMOVAL............................297
CLEANING...........................297
INSPECTION.........................297
INSTALLATION........................298
EXHAUST MANIFOLD
REMOVAL............................298
CLEANING...........................298
INSPECTION.........................298
INSTALLATION........................298
VALVE TIMING
STANDARD PROCEDURE - TIMING
VERIFICATION.......................299
GEAR HOUSING
REMOVAL............................299
INSTALLATION........................300
GEAR HOUSING COVER
REMOVAL............................301
INSTALLATION........................301
DRENGINE 5.9L DIESEL 9 - 231

ENGINE 5.9L DIESEL
DESCRIPTION
The cylinder block is constructed of cast iron. The
casting is a skirted design which incorporates longi-
tudal ribs for superior strength and noise reduction.
The block incorporates metric straight thread o-ring
fittings at lubrication oil access points. The engine
(Fig. 1) is manufactured with the cylinders being a
non-sleeved type cylinder. However, one approved
service method is to bore out the cylinders and add
cylinder sleeves to the cylinder block.
The cylinders are numbered front to rear (Fig. 2); 1
to 6. The firing order is 1±5±3±6±2±4.
Fig. 1 CumminsT24-Valve Turbo-Diesel Engine
Fig. 2 Cylinder Numbering
9 - 232 ENGINE 5.9L DIESELDR

DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTINGÐENGINE DIAGNOSIS - MECHANICAL
CONDITION POSSIBLE CAUSES CORRECTION
LUBRICATING OIL
PRESSURE LOW1. Low oil level. 1. (a) Check and fill with clean engine oil.
(b) Check for a severe external oil leak that
could reduce the pressure.
2. Oil viscosity thin, diluted or wrong
specification.2. (a) Verify the correct engine oil is being
used. (Refer to LUBRICATION &
MAINTENANCE/FLUID TYPES -
DESCRIPTION).
2. (b) Look for reduced viscosity from fuel
dilution.
3. Improperly operating pressure
switch/gauge.3. Verify the pressure switch is functioning
correctly. If not, replace switch/gauge.
4. Relief valve stuck open. 4. Check/replace valve.
6. If cooler was replaced, shipping
plugs may have been left in cooler6. Check/remove shipping plugs.
7. Worn oil pump. 7. Check and replace oil pump.
8. Suction tube loose or seal leaking. 8. Check and replace seal.
9. Loose main bearing cap. 9. Check and install new bearing. Tighten
cap to proper torque.
10. Worn bearings or wrong bearings
installed.10. Inspect and replace connecting rod or
main bearings. Check and replace directed
piston cooling nozzles.
11. Directed piston cooling nozzles
under piston, bad fit into main
carrier.11. Check directed piston cooling nozzles
position.
12. Loose oil rifle plug with saddle-jet
style nozzles12.Tighten oil rifle plug.
13. Loose directed piston cooling
nozzle.13. Tighten directed piston cooling nozzle.
14. Both J-jet and saddle jet style
cooling nozzle installed.14. Install correct style jet.
LUBRICATING OIL
PRESSURE TOO HIGH1. Pressure switch/gauge not
operating properly.1. Verify pressure switch is functioning
correctly. If not, replace switch/gauge.
DRENGINE 5.9L DIESEL 9 - 233
ENGINE 5.9L DIESEL (Continued)

CONDITION POSSIBLE CAUSES CORRECTION
2. Engine running too cold. 2. Refer to Coolant Temperature Below
Normal (Refer to 7 - COOLING -
DIAGNOSIS AND TESTING).
3. Oil viscosity too thick. 3. Make sure the correct oil is being used.
(Refer to LUBRICATION &
MAINTENANCE/FLUID TYPES -
DESCRIPTION).
4. Oil pressure relief valve stuck
closed or binding4. Check and replace valve.
LUBRICATING OIL LOSS 1. External leaks. 1. Visually inspect for oil leaks. Repair as
required.
2. Crankcase being overfilled. 2. Verify that the correct dipstick is being
used.
3. Incorrect oil specification or
viscosity.3. (a) Make sure the correct oil is being
used (Refer to LUBRICATION &
MAINTENANCE/FLUID TYPES -
DESCRIPTION).
(b) Look for reduced viscosity from dilution
with fuel.
(c) Review/reduce oil change intervals.
4. Oil cooler leak 4. Check and replace the oil cooler.
5. High blow-by forcing oil out the
breather.5. Check the breather tube area for signs of
oil loss. Perform the required repairs.
6. Turbocharger leaking oil to the air
intake.6. Inspect the air ducts for evidence of oil
transfer. Repair as required.
COMPRESSION KNOCKS 1. Air in the fuel system. 1. Identify location of air leak and repair. Do
not bleed high pressure fuel system.
2. Poor quality fuel or water/gasoline
contaminated fuel.2. Verify by operating from a temporary
tank with good fuel. Clean and flush the
fuel tank. Replace fuel/water separator filter.
3. Engine overloaded. 3. Verify the engine load rating is not being
exceeded.
4. Improperly operating injectors. 5. Check and replace misfiring/inoperative
injectors.
EXCESSIVE VIBRATION 1. Loose or broken engine mounts. 1. Replace engine mounts.
2. Damaged fan or improperly
operating accessories.2. Check and replace the vibrating
components.
3. Improperly operating vibration
damper3. Inspect/replace vibration damper.
4. Improperly operating electronically
controlled viscous fan drive.4. Inspect/replace fan drive.
5. Worn or damaged generator
bearing.5. Check/replace generator.
6. Flywheel housing misaligned. 6. Check/correct flywheel alignment.
9 - 234 ENGINE 5.9L DIESELDR
ENGINE 5.9L DIESEL (Continued)

CONDITION POSSIBLE CAUSES CORRECTION
7. Loose or broken power
component.7. Inspect the crankshaft and rods for
damage that causes an unbalance
condition. Repair/replace as required.
8. Worn or unbalanced driveline
components.8. Check/repair driveline components.
EXCESSIVE ENGINE
NOISES1. Drive belt squeal, insufficient
tension or abnormally high loading.1. Check the automatic tensioner and
inspect the drive belt. Make sure water
pump, tensioner pulley, fan hub, generator
and power steering pump turn freely.
2. Intake air or exhaust leaks. 2. Refer to Excessive Exhaust Smoke
(Refer to 9 - ENGINE - DIAGNOSIS AND
TESTING).
3. Excessive valve lash. 3. Adjust valves. Make sure the push rods
are not bent and rocker arms, adjusting
screws, crossheads, are not severely worn.
Replace bent or severely worn components.
4. Turbocharger noise. 4. Check turbocharger impeller and turbine
wheel for housing contact. Repair/replace
as required.
5. Gear train noise. 5. Visually inspect and measure gear
backlash. Replace gears as required.
6. Power function knock. 6. Check/replace rod and main bearings.
DRENGINE 5.9L DIESEL 9 - 235
ENGINE 5.9L DIESEL (Continued)