1998 DODGE RAM 1500 Cylinder head

8W-39 VEHICLE THEFT SECURITY SYSTEM
Component Page
Cylinder Lock Switch-Driver........... 8W-39-5
Data Link Connector................. 8W-39-3
Door Lock Motor/Ajar Switch-Driver..... 8W-39-5
Door Lock Motor/Ajar Switch-Left Rear . . . 8W-39-5
Door Lock Motor/Ajar Switch-Passenger . . 8W-39-4
Door Lock Motor/Ajar Switch-Right Rear . . 8W-39-4
Front Control Module................. 8W-39-3
Fuse 15............................ 8W-39-3
Fuse 23............................ 8W-39-2
Fuse 45............................ 8W-39-3
Fuse 50............................ 8W-39-2Component Page
G104.............................. 8W-39-3
G105.............................. 8W-39-3
G201.............................. 8W-39-2
G301............................ 8W-39-4, 5
Headlamp-Left...................... 8W-39-3
Headlamp-Right..................... 8W-39-3
Horn Relay......................... 8W-39-3
Instrument Cluster............... 8W-39-2, 4, 5
Integrated Power Module............ 8W-39-2, 3
Park Lamp Relay.................... 8W-39-3
Sentry Key Immobilizer Module......... 8W-39-2
DR8W-39 VEHICLE THEFT SECURITY SYSTEM 8W - 39 - 1

8W-40 INSTRUMENT CLUSTER
Component Page
A/C-Heater Control.................. 8W-40-12
Brake Transmission Shift Interlock
Solenoid........................ 8W-40-10
Center High Mounted Stop Lamp/Cargo
Lamp........................ 8W-40-5, 11
Clockspring..................... 8W-40-10, 14
Cylinder Lock Switch-Driver........... 8W-40-6
Data Link Connector................. 8W-40-5
Dome Lamp....................... 8W-40-11
Door Ajar Switch-Driver.............. 8W-40-13
Door Ajar Switch-Left Rear........... 8W-40-13
Door Ajar Switch-Passenger........... 8W-40-13
Door Ajar Switch-Right Rear.......... 8W-40-13
Door Lock Motor/Ajar Switch-Driver..... 8W-40-7
Door Lock Motor/Ajar Switch-Left Rear . . . 8W-40-7
Door Lock Motor/Ajar
Switch-Passenger................ 8W-40-6, 8
Door Lock Motor/Ajar
Switch-Right Rear............... 8W-40-7, 8
Door Lock Switch-Passenger........... 8W-40-6
Driver Door Module.................. 8W-40-8
Fog Lamp Relay..................... 8W-40-3
Fog Lamp-Left...................... 8W-40-3
Fog Lamp-Right..................... 8W-40-3
Fuse 18............................ 8W-40-5
Fuse 22............................ 8W-40-5Component Page
Fuse 41............................ 8W-40-3
G201........................... 8W-40-3, 12
G202............................. 8W-40-10
G301....................... 8W-40-2, 6, 7, 13
Glove Box Lamp And Switch.......... 8W-40-12
Headlamp Switch.................... 8W-40-3
Heated Seat Switch-Driver.......... 8W-40-8, 12
Heated Seat Switch-Passenger....... 8W-40-8, 12
Horn Switch....................... 8W-40-14
Ignition Switch................... 8W-40-5, 14
Instrument Cluster........ 8W-40-2, 3, 4, 5, 6, 7,
8, 9, 10, 11, 12, 13, 14
Integrated Power Module........ 8W-40-2, 3, 5, 9
Multi-Function Switch................ 8W-40-4
Overhead Map/Reading Lamp......... 8W-40-11
Park Brake Switch.................. 8W-40-14
Powertrain Control Module........... 8W-40-14
PTCNo.2........................ 8W-40-2, 9
Radio.......................... 8W-40-9, 11
Remote Radio Switch-Left............ 8W-40-10
Remote Radio Switch-Right........... 8W-40-10
Seat Belt Switch-Driver............... 8W-40-2
Seat Belt Tensioner Reducer........... 8W-40-2
Transfer Case Selector Switch.......... 8W-40-9
Transmission Range Sensor............ 8W-40-5
DR8W-40 INSTRUMENT CLUSTER 8W - 40 - 1

INSTRUMENT CLUSTER C2 - GRAY 16 WAY
CAV CIRCUIT FUNCTION
1 G194 20VT/LG WASH/BEAM SELECT SWITCH SIGNAL
2 G160 20VT/LG (SLT)8PASSENGER DOOR LOCK SWITCH MUX
3 G161 20VT/DG (SLT) DRIVER DOOR LOCK SWITCH MUX
4 E2 20OR/BR PANEL LAMPS DIMMER SIGNAL
5 L116 20WT/LG HEADLAMP SWITCH SIGNAL
6- -
7 G163 20VT/LB (SLT) DRIVER CYLINDER LOCK SWITCH MUX
8 L12 20WT/OR TURN LAMPS SWITCH SIGNAL
9- -
10 W52 20BR/YL INTERMITTENT WIPER SWITCH SIGNAL
11 T117 20DG/YL TRANS RANGE SENSOR ELECTRONIC CLUSTER 5
VOLT SUPPLY
12 X20 20GY/WT (SLT PREMIUM RADIO) RADIO CONTROL MUX
13 - -
14 - -
15 - -
16 - -
INSTRUMENT CLUSTER C3 - GRAY 26 WAY
CAV CIRCUIT FUNCTION
1 G75 20VT DRIVER DOOR AJAR SWITCH SENSE
2 G77 20VT/GY LEFT REAR DOOR AJAR SWITCH SENSE
3 G76 20VT/YL RIGHT REAR DOOR AJAR SWITCH SENSE
4 G74 20VT/WT PASSENGER DOOR AJAR SWITCH SENSE
5- -
6- -
7 K77 18BR/WT TRANSFER CASE POSITION SENSOR INPUT
8 L900 20WT/YL WIPER/TURN/BEAM SELECT SWITCH RETURN
9 L115 20WT/YL HEADLAMP SWITCH RETURN
10 T917 20YL/TN TRANS RANGE SENSOR ELECTRONIC CLUSTER MUX
11 - -
12 - -
13 Z18 20BK/LB GROUND
14 X3 20DG/VT HORN SWITCH SENSE
15 L50 18WT/TN BRAKE LAMP SWITCH OUTPUT
16 G15 20VT/TN KEY IN IGNITION SWITCH SENSE
17 - -
18 - -
19 D25 20WT/VT PCI BUS
20 G10 20VT/LG SEAT BELT SWITCH SENSE
21 - -
22 B25 20DG/WT PARK BRAKE SWITCH SENSE
23 F983 20PK/YL FUSED IGNITION SWITCH OUTPUT (RUN-ACC)
24 F1 16PK/WT FUSED IGNITION SWITCH OUTPUT (OFF-RUN-START)
25 F21 20PK/DG FUSED IGNITION SWITCH OUTPUT (RUN-START)
26 A114 18GY/RD FUSED B(+)
8W - 80 - 72 8W-80 CONNECTOR PIN-OUTSDR

CONNECTOR NAME/NUMBER COLOR LOCATION FIG.
C315 DK GY At Driver Seat N/S
C316 BK At Passenger Seat N/S
C317 BK At Passenger Seat N/S
C319 BK Bottom Left of Left Door N/S
C320 Right Rear Door 43
C322 DK GY Left Rear of Frame 44, 46
C323 BK Left Side of Instrument Panel N/S
C327 BK Right Rear Fender 50, 51
C328 BK Left Rear Fender 50, 51, 52
Camshaft Position Sensor GY Right Front Side of Engine 3, 9
Capacitor Left Rear of Engine Compartment 4
Center High Mounted Stop
Lamp/Cargo LampBK Rear of Cab 49
Cigar Lighter Outlet NAT Rear of Cigar Lighter 32, 35, 36
Clearance Lamp No. 1 BK Left Roof 48
Clearance Lamp No. 2 BK Left-Center Roof 48
Clearance Lamp No. 3 BK Center Roof 48
Clearance Lamp No. 4 BK Right-Center Roof 48
Clearance Lamp No. 5 BK Right Roof 48
Clockspring C1 BK Steering Column 31
Clockspring C2 YL Steering Column 31
Clockspring C3 BK Steering Column N/S
Clockspring C4 BK Steering Column N/S
Clutch Interlock Brake Switch BK At Clutch Pedal 22, 24
Coil On Plug No.1 BK Left Top Side of Intake Manifold 6
Coil On Plug No.2 BK Right Top Side of Intake Manifold 3
Coil On Plug No.3 BK Left Top Side of Intake Manifold 6
Coil On Plug No.4 BK Right Top Side of Intake Manifold 3
Coil On Plug No.5 BK Left Top Side of Intake Manifold 5, 6
Coil On Plug No.6 BK Right Top Side of Intake Manifold 3
Coil On Plug No.7 BK Left Top Side of Intake Manifold 6
Coil On Plug No.8 BK Right Top Side of Intake Manifold 3
Compass/Mini-Trip Computer BK In Overhead Console N/S
Condenser Fan BK Near Condenser 23, 24
Controller Anti-Lock Brake C1 BK Left Fender Side Shield 22, 24, 25
Controller Anti-Lock Brake C2
(ABS)BK Left Fender Side Shield 22, 25
Crankshaft Position Sensor BK Right Rear of Engine Block 3, 9
Cylinder Lock Switch-Driver
(Premium)BK In Left Front Door 41
Cylinder Lock Switch-Passenger
(Premium)LT GY In Right Front Door N/S
Data Link Connector BK Left Bottom of Instrument Panel 35, 38
DR8W-91 CONNECTOR/GROUND/SPLICE LOCATION 8W - 91 - 3
CONNECTOR/GROUND/SPLICE LOCATION (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 - 3.7L
DESCRIPTION
The 3.7 liter (226 CID) six-cylinder engine is an
90É single overhead camshaft engine (Fig. 1). The
cast iron cylinder block is made up of two different
components; the first component is the cylinder bore
and upper block, the second component is the bed-
plate that comprises the lower portion of the cylinderblock and houses the lower half of the crankshaft
main bearings. The cylinders are numbered from
front to rear with the left bank being numbered 1,3,
and 5 and the right bank being numbered 2,4, and 6.
The firing order is 1±6±5±4±3±2. The engine serial
number is located at the right front side of the
engine block
Fig. 1 3.7 L ENGINE
DRENGINE - 3.7L 9 - 3

DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTING - ENGINE
DIAGNOSIS - INTRODUCTION
Engine diagnosis is helpful in determining the
causes of malfunctions not detected and remedied by
routine maintenance.
These malfunctions may be classified as either per-
formance (e.g., engine idles rough and stalls) or
mechanical (e.g., a strange noise).
(Refer to 9 - ENGINE - DIAGNOSIS AND TEST-
ING) - PERFORMANCE and (Refer to 9 - ENGINE -
DIAGNOSIS AND TESTING)ÐMECHANICAL for
possible causes and corrections of malfunctions.
(Refer to 14 - FUEL SYSTEM/FUEL DELIVERY -
DIAGNOSIS AND TESTING) and (Refer to 14 -
FUEL SYSTEM/FUEL INJECTION - DIAGNOSIS
AND TESTING) for the fuel system diagnosis.Additional tests and diagnostic procedures may be
necessary for specific engine malfunctions that can
not be isolated with the Service Diagnosis charts.
Information concerning additional tests and diagno-
sis is provided within the following diagnosis:
²Cylinder Compression Pressure Test (Refer to 9 -
ENGINE - DIAGNOSIS AND TESTING).
²Cylinder Combustion Pressure Leakage Test
(Refer to 9 - ENGINE - DIAGNOSIS AND TEST-
ING).
²Engine Cylinder Head Gasket Failure Diagnosis
(Refer to 9 - ENGINE/CYLINDER HEAD - DIAGNO-
SIS AND TESTING).
²Intake Manifold Leakage Diagnosis (Refer to 9 -
ENGINE/MANIFOLDS/INTAKE MANIFOLD -
DIAGNOSIS AND TESTING).
DIAGNOSIS AND TESTING - ENGINE DIAGNOSIS - PERFORMANCE
CONDITION POSSIBLE CAUSE CORRECTION
ENGINE WILL NOT START 1. Weak battery 1. Charge or replace as necessary.
2. Corroded or loose battery
connections.2. Clean and tighten battery
connections. Apply a coat of light
mineral grease to the terminals.
3. Faulty starter. 3. (Refer to 8 - ELECTRICAL/
STARTING - DIAGNOSIS AND
TESTING).
4. Faulty coil or control unit. 4. (Refer to 8 - ELECTRICAL/
IGNITION CONTROL/IGNITION
COIL - REMOVAL).
5. Incorrect spark plug gap. 5. (Refer to 8 - ELECTRICAL/
IGNITION CONTROL/SPARK PLUG
- CLEANING).
6. Incorrect right bank cam timing. 6. Refer to engine timing in this
section.
7. Dirt or water in fuel system. 7. Clean system and replace fuel
filter.
8.Faulty fuel pump, relay or wiring. 8.Repair or replace as necessary.
9. Faulty cam or crank sensor 9. Refer to Ignition system.
ENGINE STALLS OR ROUGH IDLE 1. Vacuum leak. 1. Inspect intake manifold and
vacuum hoses, repair or replace as
necessary.
2. Faulty crank position sensor 2. Replace crank position sensor.
3. Faulty coil. 3. (Refer to 8 - ELECTRICAL/
IGNITION CONTROL/IGNITION
COIL - REMOVAL).
9 - 4 ENGINE - 3.7LDR
ENGINE - 3.7L (Continued)

CONDITION POSSIBLE CAUSE CORRECTION
4. Incorrect cam timing. 4. (Refer to 9 - ENGINE/VALVE
TIMING - STANDARD
PROCEDURE).
1. ENGINE LOSS OF POWER 1. Dirty or incorrectly gapped spark
plugs.1. (Refer to 8 - ELECTRICAL/
IGNITION CONTROL/SPARK PLUG
- CLEANING).
2. Dirt or water in fuel system. 2. Clean system and replace fuel
filter.
3. Faulty fuel pump. 3. (Refer to 14 - FUEL SYSTEM/
FUEL DELIVERY/FUEL PUMP -
DIAGNOSIS AND TESTING).
4. Blown cylinder head gasket. 4. Replace cylinder head gasket.
5. Low compression. 5. (Refer to 9 - ENGINE -
DIAGNOSIS AND TESTING), repair
as necessary.
6. Burned, warped or pitted valves. 6. Replace as necessary.
7. Plugged or restricted exhaust
system.7. Inspect and replace as
necessary.
8. Faulty coil. 8. (Refer to 8 - ELECTRICAL/
IGNITION CONTROL/IGNITION
COIL - REMOVAL).
9. Incorrect cam timing. 9. Refer to Engine TIming in this
section.
1. ENGINE MISSES ON
ACCELERATION1. Spark plugs dirty or incorrectly
gapped.1. (Refer to 8 - ELECTRICAL/
IGNITION CONTROL/SPARK PLUG
- CLEANING).
2. Dirt in fuel system. 2. Clean fuel system.
3. Burned, warped or pitted valves. 3. Replcae as necessary.
4. Faulty coil. 4. (Refer to 8 - ELECTRICAL/
IGNITION CONTROL/IGNITION
COIL - REMOVAL).
1. ENGINE MISSES AT HIGH
SPEED1. Spark plugs dirty or incorrectly
gapped.1. (Refer to 8 - ELECTRICAL/
IGNITION CONTROL/SPARK PLUG
- CLEANING).
2. Faulty coil. 2. (Refer to 8 - ELECTRICAL/
IGNITION CONTROL/IGNITION
COIL - REMOVAL).
3. Dirt or water in fuel system. 3. Clean system and replace fuel
filter.
DRENGINE - 3.7L 9 - 5
ENGINE - 3.7L (Continued)