Valve DODGE RAM 1500 1998 2.G Repair Manual

INSPECTION - WIPER & WASHER SYSTEM
WIPER SYSTEM
The wiper blades and wiper arms should be
inspected periodically, not just when wiper perfor-
mance problems are experienced. This inspection
should include the following points:
(1) Inspect the wiper arms for any indications of
damage, or contamination. If the wiper arms are con-
taminated with any foreign material, clean them as
required. (Refer to 8 - ELECTRICAL/WIPERS/
WASHERS - CLEANING). If a wiper arm is damaged
or corrosion is evident, replace the wiper arm with a
new unit. Do not attempt to repair a wiper arm that
is damaged or corroded.
(2) Carefully lift the wiper blade off of the glass.
Note the action of the wiper arm hinge. The wiper
arm should pivot freely at the hinge, but with no lat-
eral looseness evident. If there is any binding evident
in the wiper arm hinge, or there is evident lateral
play in the wiper arm hinge, replace the wiper arm.
CAUTION: Do not allow the wiper arm to spring
back against the glass without the wiper blade in
place or the glass may be damaged.
(3) Once proper hinge action of the wiper arm is
confirmed, check the hinge for proper spring tension.
Remove the wiper blade from the wiper arm. Either
place a small postal scale between the blade end of
the wiper arm and the glass, or carefully lift the
blade end of the arm away from the glass using a
small fish scale. Compare the scale readings between
the right and left wiper arms. Replace a wiper arm if
it has comparatively lower spring tension, as evi-
denced by a lower scale reading.
(4) Inspect the wiper blades and squeegees for any
indications of damage, contamination, or rubber dete-
rioration (Fig. 2). If the wiper blades or squeegees
are contaminated with any foreign material, clean
them and the glass as required. (Refer to 8 - ELEC-
TRICAL/WIPERS/WASHERS - CLEANING). After
cleaning the wiper blade and the glass, if the wiper
blade still fails to clear the glass without smearing,
streaking, chattering, hazing, or beading, replace the
wiper blade. Also, if a wiper blade is damaged or the
squeegee rubber is damaged or deteriorated, replace
the wiper blade with a new unit. Do not attempt to
repair a wiper blade that is damaged.
WASHER SYSTEM
The washer system components should be
inspected periodically, not just when washer perfor-
mance problems are experienced. This inspection
should include the following points:(1) Check for ice or other foreign material in the
washer reservoir. If contaminated, clean and flush
the washer system. (Refer to 8 - ELECTRICAL/WIP-
ERS/WASHERS - CLEANING).
(2) Inspect the washer plumbing for pinched, leak-
ing, deteriorated, or incorrectly routed hoses and
damaged or disconnected hose fittings. Replace dam-
aged or deteriorated hoses and hose fittings. Leaking
washer hoses can sometimes be repaired by cutting
the hose at the leak and splicing it back together
using an in-line connector fitting. Similarly, sections
of deteriorated hose can be cut out and replaced by
splicing in new sections of hose using in-line connec-
tor fittings. Whenever routing a washer hose or a
wire harness containing a washer hose, it must be
routed away from hot, sharp, or moving parts. Also,
sharp bends that might pinch the washer hose must
be avoided.CHECK VALVE
DESCRIPTION
A single washer system check valve is standard
equipment on this model, and is installed in the
Fig. 2 Wiper Blade Inspection
1 - WORN OR UNEVEN EDGES
2 - ROAD FILM OR FOREIGN MATERIAL DEPOSITS
3 - HARD, BRITTLE, OR CRACKED
4 - DEFORMED OR FATIGUED
5 - SPLIT
6 - DAMAGED SUPPORT COMPONENTS
DRWIPERS/WASHERS 8R - 7
WIPERS/WASHERS (Continued)

washer system plumbing (Fig. 3). The check valve is
integral to the washer nozzle plumbing wye fitting
located in the cowl plenum area beneath the cowl
plenum cover/grille panel near the base of the wind-
shield. The check valve consists of a molded plastic
body with a raised arrowhead molded into its center
section that indicates the direction of the flow
through the valve, and three barbed hose nipples
formed in a wye configuration on the outside circum-
ference of the center section of the valve body. The
check valve cannot be adjusted or repaired and, if
faulty or damaged, it must be replaced.
OPERATION
The check valve provides more than one function
in this application. It serves as a wye connector fit-
ting between the engine compartment and washer
nozzle sections of the washer supply hose. It prevents
washer fluid from draining out of the washer supply
hoses back to the washer reservoir. This drain-back
would result in a lengthy delay from when the
washer switch is actuated until washer fluid was dis-
pensed through the washer nozzles, because the
washer pump would have to refill the washer plumb-
ing from the reservoir to the nozzles. Such a drain-
back condition could also result in water, dirt, or
other outside contaminants being siphoned into the
washer system through the washer nozzle orifice.
This water could subsequently freeze and plug the
nozzle, while other contaminants could interfere with
proper nozzle operation and cause improper nozzle
spray patterns. In addition, the check valve prevents
washer fluid from siphoning through the washer noz-
zles after the washer system is turned Off.When the washer pump pressurizes and pumps
washer fluid from the reservoir through the washer
plumbing, the fluid pressure unseats a diaphragm
from over a sump well within the valve by overriding
the spring pressure applied to it by a piston (Fig. 4).
With the diaphragm unseated, washer fluid is
allowed to flow toward the two washer nozzles. When
the washer pump stops operating, the spring pres-
sure on the piston seats the diaphragm over the
sump well in the valve and fluid flow in either direc-
tion within the washer plumbing is prevented. The
check valve cannot be adjusted or repaired and, if
faulty or damaged, it must be replaced.REMOVAL
(1) Remove both wiper arms from the wiper pivots.
(Refer to 8 - ELECTRICAL/WIPERS/WASHERS/
WIPER ARM - REMOVAL).
(2) Unlatch and open the hood.
(3) Remove the cowl plenum cover/grille panel
from over the cowl plenum. (Refer to 23 - BODY/EX-
TERIOR/COWL GRILLE - REMOVAL).
(4) From the underside of the cowl plenum cover/
grille panel, disconnect the cowl plenum and washer
nozzle hoses from the three barbed nipples of the
check valve (Fig. 5).
(5) Remove the check valve from the underside of
the cowl plenum cover/grille panel.
INSTALLATION
(1) Position the check valve to the underside of the
cowl plenum cover/grille panel (Fig. 5). Be certain
that the flow direction arrow molded into the check
valve body is oriented towards the washer nozzles.
Fig. 3 Check Valve
1 - INLET NIPPLE
2 - CHECK VALVE
3 - OUTLET NIPPLE (2)
4 - FLOW DIRECTION ARROW
Fig. 4 Check Valve
1 - SPRING
2 - PISTON
3 - DIAPHRAGM
4 - TO WASHER NOZZLE
5 - FROM WASHER PUMP
8R - 8 WIPERS/WASHERSDR
CHECK VALVE (Continued)

(2) From the underside of the cowl plenum cover/
grille panel, reconnect the cowl plenum and washer
nozzle hoses to the three barbed nipples of the check
valve.
(3) Reinstall the cowl plenum cover/grille panel
over the cowl plenum. (Refer to 23 - BODY/EXTERI-
OR/COWL GRILLE - INSTALLATION).
(4) Close and latch the hood.
(5) Reinstall both wiper arms onto the wiper piv-
ots. (Refer to 8 - ELECTRICAL/WIPERS/WASHERS/
WIPER ARM - INSTALLATION).
WASHER FLUID LEVEL
SWITCH
DESCRIPTION
The washer fluid level switch is a single pole, sin-
gle throw reed-type switch mounted on the outboard
side of the of the washer reservoir in the engine com-
partment (Fig. 6). Only the molded plastic switch
mounting flange and the integral connector recepta-
cle are visible when the switch is installed in the res-
ervoir. A short nipple formation extends from the
inner surface of the switch mounting flange, and a
barb on the nipple near the switch mounting flange
is pressed through a rubber grommet seal installed
in the mounting hole of the reservoir.
A small, molded plastic float has two pivot pins
near its center that are snapped into two receptacles
near the ends of two stanchions that extend toward
the float from the switch nipple formation. A small
magnet is secured within the end of the float nearestthe switch nipple formation, and a reed switch is con-
cealed within the nipple. A diagnostic resistor is con-
nected between the two switch terminals within the
switch mounting flange. The washer fluid level
switch cannot be adjusted or repaired. If faulty or
damaged, the switch must be replaced.
OPERATION
The washer fluid level switch uses a pivoting,
oblong float to monitor the level of the washer fluid
in the washer reservoir. The float contains a small
magnet. When the float pivots, the proximity of this
magnet to a stationary reed switch within the nipple
formation of the switch changes. When the fluid level
in the washer reservoir is at or above the float level,
the float moves to a vertical position, the influence of
the float magnetic field is removed from the reed
switch, and the normally open reed switch contacts
open. When the fluid level in the washer reservoir
falls below the level of the pivoting float, the float
moves to a horizontal position, the influence of the
float magnetic field is applied to the reed switch, and
the contacts of the normally open reed switch close.
The washer fluid level switch is connected to the
vehicle electrical system through a dedicated take
out and connector of the right (except diesel engines)
or left (diesel engines only) headlamp and dash wire
harness. The switch is connected in series between a
clean ground output of the Front Control Module
Fig. 5 Check Valve Remove/Install
1 - WASHER NOZZLE HOSE (RIGHT)
2 - CHECK VALVE
3 - ROUTING CLIP
4 - COWL PLENUM WASHER HOSE
5 - COWL PLENUM COVER/GRILLE PANEL (UNDERSIDE)
6 - WASHER NOZZLE HOSE (LEFT)
Fig. 6 Washer Fluid Level Switch
1 - MOUNTING FLANGE
2 - BARBED NIPPLE
3 - FLOAT
4 - RESERVOIR
5 - GROMMET SEAL
6 - PIVOT
7 - MAGNET
8 - CONNECTOR RECEPTACLE
DRWIPERS/WASHERS 8R - 9
CHECK VALVE (Continued)

INSTALLATION
(1) Install a new rubber grommet seal into the
washer fluid level switch mounting hole in the
washer reservoir. Always use a new rubber grommet
seal on the reservoir.
(2) Insert the float of the washer fluid level switch
through the rubber grommet seal and into the
washer reservoir. The connector receptacle of the
washer fluid level switch should be pointed upward.
(3) Using hand pressure, press firmly and evenly
on the washer fluid level switch mounting flange
until the barbed nipple is fully seated in the rubber
grommet seal in the washer reservoir mounting hole.
(4) Reconnect the right (except diesel engine) or
left (diesel engine only) headlamp and dash wire har-
ness connector for the washer fluid level switch to
the switch connector receptacle (Fig. 7) or (Fig. 8).
(5) Reconnect the removed washer hose to the
barbed outlet nipple of the washer pump/motor unit.
(6) Refill the washer reservoir with the washer
fluid drained from the reservoir during the removal
procedure.
(7) Reconnect the battery negative cable.
(8) Close and latch the hood.
WASHER HOSES/TUBES
DESCRIPTION
The washer plumbing consists of a small diameter
rubber reservoir washer hose that is routed from the
barbed outlet nipple of the electric washer pump/mo-tor unit on the washer reservoir through a trough
molded into the back of the reservoir above the
washer pump and to the engine compartment washer
hose (Fig. 9). On models equipped with an optional
diesel engine, the reservoir washer hose is routed
through routing clips on the top of the radiator fan
shroud from the washer reservoir on the left side of
the radiator to the engine compartment washer hose
on the right side of the radiator. The engine compart-
ment washer hose is contained within the right head-
lamp and dash wire harness, which is routed through
the engine compartment along the top of the right
front fender wheel house to the dash panel.
The engine compartment washer hose is connected
to the washer reservoir washer hose and to the cowl
plenum washer hose with molded plastic in-line fit-
tings that have a barbed nipple on each end. The
cowl plenum washer hose is routed from the engine
compartment into the cowl plenum area through a
trough formation located near the right end of the
cowl plenum cover/grille panel. The cowl plenum
washer hose is connected to the washer system check
valve/wye fitting on the underside of the cowl plenum
cover/grille panel. The cowl plenum washer hose and
the two washer nozzle hoses are routed through inte-
gral routing clips on the underside of the cowl ple-
num cover/grille panel. The cowl plenum washer hose
is connected to one nipple on the wye fitting and the
two washer nozzle hoses are connected to the other
two wye fitting nipples. The washer nozzle hoses are
then routed along the underside of the cowl plenum
cover/grille panel to the two washer nozzles.
Washer hose is available for service only as roll
stock, which must then be cut to length. The molded
plastic washer hose fittings cannot be repaired. If
these fittings are faulty or damaged, they must be
replaced.
OPERATION
Washer fluid in the washer reservoir is pressurized
and fed by the washer pump/motor through the
washer system plumbing and fittings to the two
washer nozzles. Whenever routing the washer hose
or a wire harness containing a washer hose, it must
be routed away from hot, sharp, or moving parts;
and, sharp bends that might pinch the hose must be
avoided.
WASHER NOZZLE
DESCRIPTION
The two washer nozzles have integral snap fea-
tures and an anti-rotation tab that secure them in
dedicated holes in the cowl plenum cover/grille panel
located near the base of the windshield (Fig. 10). The
Fig. 9 Engine Compartment Washer Hose
1 - RIGHT FENDER
2 - RIGHT HEADLAMP & DASH WIRE HARNESS
3 - ENGINE COMPARTMENT WASHER HOSE (TO COWL
PLENUM)
4 - COWL PLENUM WASHER HOSE
5 - ENGINE COMPARTMENT WASHER HOSE (TO WASHER
RESERVOIR)
DRWIPERS/WASHERS 8R - 11
WASHER FLUID LEVEL SWITCH (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

REMOVAL.............................38
INSTALLATION.........................38
ENGINE BLOCK
DESCRIPTION.........................38
STANDARD PROCEDURE - CYLINDER BORE
HONING............................38
CLEANING............................39
INSPECTION..........................39
CRANKSHAFT
DESCRIPTION.........................40
REMOVAL.............................40
INSPECTION..........................41
INSTALLATION.........................42
CRANKSHAFT MAIN BEARINGS
STANDARD PROCEDURE
MAIN BEARING FITTING................44
CRANKSHAFT OIL SEAL - FRONT
REMOVAL.............................46
INSTALLATION.........................46
CRANKSHAFT OIL SEAL - REAR
REMOVAL.............................47
INSTALLATION.........................47
FLEX PLATE
REMOVAL.............................48
INSTALLATION.........................48
PISTON & CONNECTING ROD
DESCRIPTION.........................48
STANDARD PROCEDURE
CONNECTING ROD BEARING FITTING....49
STANDARD PROCEDURE - PISTON FITTING..51
REMOVAL.............................51
CLEANING............................52
INSPECTION..........................52
INSTALLATION.........................52
PISTON RINGS
STANDARD PROCEDURE - PISTON RING
FITTING.............................53
VIBRATION DAMPER
REMOVAL.............................55
INSTALLATION.........................56
STRUCTURAL COVER
DESCRIPTION.........................57
OPERATION...........................57
REMOVAL.............................57
INSTALLATION.........................57
FRONT MOUNT
REMOVAL.............................58
INSTALLATION.........................59
REAR MOUNT
REMOVAL.............................61
INSTALLATION.........................61
LUBRICATION
DESCRIPTION.........................61
OPERATION...........................61
DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTING - ENGINE OIL
LEAK...............................64DIAGNOSIS AND TESTING - CHECKING
ENGINE OIL PRESSURE................65
DIAGNOSIS AND TESTING - REAR SEAL
AREA LEAKS.........................65
OIL PAN
DESCRIPTION.........................66
REMOVAL.............................66
CLEANING............................66
INSPECTION..........................66
INSTALLATION.........................66
OIL PRESSURE SENSOR/SWITCH
DESCRIPTION.........................67
OPERATION...........................67
REMOVAL.............................67
INSTALLATION.........................67
OIL PUMP
REMOVAL.............................67
DISASSEMBLY.........................68
INSPECTION..........................68
ASSEMBLY............................69
INSTALLATION.........................69
OIL FILTER
REMOVAL.............................70
INSTALLATION.........................70
OIL
STANDARD PROCEDURE - ENGINE OIL
SERVICE............................71
INTAKE MANIFOLD
DESCRIPTION.........................72
DIAGNOSIS AND TESTING - INTAKE
MANIFOLD LEAKS.....................72
REMOVAL.............................73
INSTALLATION.........................73
EXHAUST MANIFOLD
DESCRIPTION.........................74
REMOVAL.............................74
INSTALLATION.........................74
VALVE TIMING
DESCRIPTION.........................76
OPERATION...........................76
STANDARD PROCEDURE
MEASURING TIMING CHAIN WEAR.......77
SERVICE PROCEDURE - TIMING
VERIFICATION........................77
BALANCE SHAFT
REMOVAL.............................80
INSTALLATION.........................80
IDLER SHAFT
REMOVAL.............................81
INSTALLATION.........................81
TIMING BELT / CHAIN COVER(S)
REMOVAL.............................81
INSTALLATION.........................81
TIMING BELT/CHAIN AND SPROCKETS
REMOVAL.............................83
INSPECTION..........................84
INSTALLATION.........................85
9 - 2 ENGINE - 3.7LDR

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)

DIAGNOSIS AND TESTING - ENGINE DIAGNOSIS - MECHANICAL
CONDITION POSSIBLE CAUSES CORRECTIONS
NOISY VALVES 1. High or low oil level in
crankcase.1. (Refer to LUBRICATION &
MAINTENANCE -
SPECIFICATIONS)
2. Thin or diluted oil. 2. Change oil and filter.
3. Low oil pressure. 3. Check oil pump, if Ok, check rod
and main bearings for excessive
wear.
4. Dirt in lash adjusters. 4. Replace as necessary.
5. Worn rocker arms. 5. Replace as necessary.
6. Worn lash adjusters 6. Replace as necessary.
7. Worn valve guides. 7. (Refer to 9 - ENGINE/CYLINDER
HEAD/INTAKE/EXHAUST VALVES
& SEATS - STANDARD
PROCEDURE)
8. Excessive runout of valve seats
on valve faces.8. (Refer to 9 - ENGINE/CYLINDER
HEAD/INTAKE/EXHAUST VALVES
& SEATS - STANDARD
PROCEDURE)
CONNECTING ROD NOISE 1. Insufficient oil supply. 1. (Refer to LUBRICATION &
MAINTENANCE -
SPECIFICATIONS)
2. Low oil pressure. 2. Check oil pump, if Ok, check rod
and main bearings for excessive
wear.
3. Thin or diluted oil. 3. Change oil and filter.
4. Excessive bearing clearance. 4. Replace as necessary.
5. Connecting rod journal
out-of-round.5. Service or replace crankshaft.
6. Misaligned connecting rods. 6. Replace bent connecting rods.
MAIN BEARING NOISE 1. Insufficient oil supply. 1. (Refer to LUBRICATION &
MAINTENANCE -
SPECIFICATIONS)
2. Low oil pressure. 2. Check oil pump, if Ok, check rod
and main bearings for excessive
wear.
3. Thin or diluted oil. 3. Change oil and filter.
4. Excessive bearing clearance. 4. Replace as necessary.
5. Excessive end play. 5. Check thrust washers for wear.
6. Crankshaft journal out-of round. 6. Service or replace crankshaft.
7. Loose flywheel or torque
converter.7. Tighten to correct torque
9 - 6 ENGINE - 3.7LDR
ENGINE - 3.7L (Continued)

DIAGNOSIS AND TESTING - ENGINE 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 (Refer to 9
- ENGINE/ENGINE BLOCK/
CRANKSHAFT OIL SEAL - REAR -
REMOVAL).
3. Crankshaft seal flange.
Scratched, nicked or grooved.3. Polish or replace crankshaft.
4. Oil pan flange cracked. 4. Replace oil pan (Refer to 9 -
ENGINE/LUBRICATION/OIL PAN -
REMOVAL).
5. Timing chain cover seal,
damaged or misaligned.5. Replace seal (Refer to 9 -
ENGINE/ENGINE BLOCK/
CRANKSHAFT OIL SEAL - FRONT
- REMOVAL).
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 (Refer to 9
- ENGINE/LUBRICATION/OIL
PRESSURE SENSOR/SWITCH -
REMOVAL).
3. Low oil pressure. 3. Check oil pump and bearing
clearance.
4. Clogged oil filter. 4. Replace oil filter (Refer to 9 -
ENGINE/LUBRICATION/OIL FILTER
- REMOVAL).
5. Worn oil pump. 5. Replace oil pump (Refer to 9 -
ENGINE/LUBRICATION/OIL PUMP
- REMOVAL).
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 (Refer to 9 -
ENGINE/LUBRICATION/OIL PUMP
- REMOVAL).
9. Oil pick up tube loose, damaged
or clogged.9. Replace as necessary.
DRENGINE - 3.7L 9 - 7
ENGINE - 3.7L (Continued)

CONDITION POSSIBLE CAUSES CORRECTION
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 (Refer to 9 -
ENGINE/ENGINE BLOCK/PISTON
RINGS - STANDARD
PROCEDURE).
3. Incorrect ring size installed. 3. Replace rings (Refer to 9 -
ENGINE/ENGINE BLOCK/PISTON
RINGS - STANDARD
PROCEDURE).
4. Worn valve guides. 4. Ream guides and replace valves
(Refer to 9 - ENGINE/CYLINDER
HEAD/INTAKE/EXHAUST VALVES
& SEATS - STANDARD
PROCEDURE).
5. Leaking valve guide seals. 5. Replace valve guide seals.
DIAGNOSIS AND TESTING - CYLINDER
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.
(3) Disable the fuel system (Refer to 14 - FUEL
SYSTEM/FUEL DELIVERY - DESCRIPTION).
(4) Remove the ASD relay (Refer to 8 - ELECTRI-
CAL/IGNITION CONTROL/AUTO SHUT DOWN
RELAY - REMOVAL).
(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 3rd
revolution. Continue the test for the remaining cylin-
ders.
(7) (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
jacket.
²Any causes for combustion/compression pressure
loss.
(1) Check the coolant level and fill as required. DO
NOT install the radiator cap.
(2) Start and operate the engine until it attains
normal operating temperature, then turn the engine
OFF.
(3) Remove the spark plugs.
(4) Remove the oil filler cap.
(5) Remove the air cleaner hose.
(6) Calibrate the tester according to the manufac-
turer'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.
(7) Perform the test procedures on each cylinder
according to the tester manufacturer's instructions.
Set piston of cylinder to be tested at TDC compres-
sion,While testing, listen for pressurized air escaping
through the throttle body, tailpipe and 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.
Refer to CYLINDER COMBUSTION PRESSURE
LEAKAGE DIAGNOSIS CHART.
9 - 8 ENGINE - 3.7LDR
ENGINE - 3.7L (Continued)