1998 DODGE RAM 1500 belt

(5) Install the timing chain cover (Refer to 9 -
ENGINE/VALVE TIMING/TIMING BELT / CHAIN
COVER(S) - INSTALLATION).
(6) Install the pick-up tube and oil pan (Refer to 9
- ENGINE/LUBRICATION/OIL PAN - INSTALLA-
TION).
OIL FILTER
REMOVAL
All engines are equipped with a high quality full-
flow, disposable type oil filter. DaimlerChrysler Cor-
poration recommends a Mopartor equivalent oil
filter be used.
(1) Position a drain pan under the oil filter.
(2) Using a suitable oil filter wrench loosen filter.
(3) Rotate the oil filter counterclockwise (Fig. 83)
to remove it from the cylinder block oil filter boss.
(4) When filter separates from cylinder block oil
filter boss, tip gasket end upward to minimize oil
spill. Remove filter from vehicle.
NOTE: Make sure filter gasket was removed with fil-
ter.
(5) With a wiping cloth, clean the gasket sealing
surface of oil and grime.
INSTALLATION
(1) Lightly lubricate oil filter gasket with engine
oil.
(2) Thread filter onto adapter nipple. When gasket
makes contact with sealing surface, (Fig. 84) hand
tighten filter one full turn, do not over tighten.
(3) Add oil, verify crankcase oil level and start
engine. Inspect for oil leaks.
Fig. 82 Oil Pump And Primary Timing Chain
Tensioner Tightening SequenceFig. 83 OIL FILTER
1 - ENGINE OIL FILTER
Fig. 84 Oil Filter Sealing Surface-Typical
1 - SEALING SURFACE
2 - RUBBER GASKET
3 - OIL FILTER
9 - 70 ENGINE - 3.7LDR
OIL PUMP (Continued)

CRANKCASE OIL LEVEL INSPECTION
CAUTION: Do not overfill crankcase with engine oil,
pressure loss or oil foaming can result.
Inspect engine oil level approximately every 800
kilometers (500 miles). Unless the engine has exhib-
ited loss of oil pressure, run the engine for about five
minutes before checking oil level. Checking engine oil
level on a cold engine is not accurate.
To ensure proper lubrication of an engine, the
engine oil must be maintained at an acceptable level.
The acceptable levels are indicated between the ADD
and SAFE marks on the engine oil dipstick.
(1) Position vehicle on level surface.
(2) With engine OFF, allow approximately ten min-
utes for oil to settle to bottom of crankcase, remove
engine oil dipstick.
(3) Wipe dipstick clean.
(4) Install dipstick and verify it is seated in the
tube.
(5) Remove dipstick, with handle held above the
tip, take oil level reading.
(6) Add oil only if level is below the ADD mark on
dipstick.
ENGINE OIL CHANGE
Change engine oil at mileage and time intervals
described in Maintenance Schedules.
Run engine until achieving normal operating tem-
perature.
(1) Position the vehicle on a level surface and turn
engine off.
(2) Hoist and support vehicle on safety stands.
(3) Remove oil fill cap.
(4) Place a suitable drain pan under crankcase
drain.
(5) Remove drain plug from crankcase and allow
oil to drain into pan. Inspect drain plug threads for
stretching or other damage. Replace drain plug if
damaged.
(6) Install drain plug in crankcase.
(7) Lower vehicle and fill crankcase with specified
type and amount of engine oil described in this sec-
tion.
(8) Install oil fill cap.
(9) Start engine and inspect for leaks.
(10) Stop engine and inspect oil level.
USED ENGINE OIL DISPOSAL
Care should be exercised when disposing used
engine oil after it has been drained from a vehicle
engine. Refer to the WARNING at beginning of this
section.
INTAKE MANIFOLD
DESCRIPTION
The intake manifold (Fig. 88) is made of a compos-
ite material and features 300 mm (11.811 in.) long
runners which maximizes low end torque. The intake
manifold uses single plane sealing which consist of
six individual press in place port gaskets to prevent
leaks. The throttle body attaches directly to the
intake manifold. Eight studs and two bolts are used
to fasten the intake to the head.
DIAGNOSIS AND TESTING - INTAKE
MANIFOLD LEAKS
An intake manifold air leak is characterized by
lower than normal manifold vacuum. Also, one or
more cylinders may not be functioning.
WARNING: USE EXTREME CAUTION WHEN THE
ENGINE IS OPERATING. DO NOT STAND IN A
DIRECT LINE WITH THE FAN. DO NOT PUT YOUR
HANDS NEAR THE PULLEYS, BELTS OR THE FAN.
DO NOT WEAR LOOSE CLOTHING.
Fig. 88 Intake Manifold
1 - THROTTLE BODY
2 - INTAKE MANIFOLD
3 - INTAKE PORT GASKETS
9 - 72 ENGINE - 3.7LDR
OIL (Continued)

block. A large washer on the idler shaft bolt and the
rear flange of the idler shaft are used to control
sprocket thrust movement. Pressurized oil is routed
through the center of the idler shaft to provide lubri-
cation for the two bushings used in the idler sprocket
assembly.
There are two secondary drive chains, both are
roller type, one to drive the camshaft in each SOHC
cylinder head. There are no shaft speed changes in
the secondary chain drive system. Each secondary
chain drives a 26 tooth cam sprocket directly from
the 26 tooth sprocket on the idler sprocket assembly.
A fixed chain guide and a hydraulic oil damped ten-
sioner are used to maintain tension in each second-
ary chain system. The hydraulic tensioners for the
secondary chain systems are fed pressurized oil from
oil reservoir pockets in the block. Each tensioner
incorporates a controlled leak path through a device
known as a vent disc located in the nose of the piston
to manage chain loads. Each tensioner also has a
mechanical ratchet system that limits chain slack if
the tensioner piston bleeds down after engine shut
down. The tensioner arms and guides also utilize
nylon wear faces for low friction and long wear. The
secondary timing chains receive lubrication from a
small orifice in the tensioners. This orifice is pro-
tected from clogging by a fine mesh screen which is
located on the back of the hydraulic tensioners.
STANDARD PROCEDURE
MEASURING TIMING CHAIN WEAR
NOTE: This procedure must be performed with the
timing chain cover removed.
(1) Remove the timing chain cover (Refer to 9 -
ENGINE/VALVE TIMING/TIMING BELT/CHAIN
AND SPROCKETS - REMOVAL).
(2) To determine if the secondary timing chains
are worn, rotate the engine clockwise until maximum
tensioner piston extension is obtained. Measure the
distance between the secondary timing chain ten-
sioner housing and the step ledge on the piston. The
measurement at point (A) must be less than 15mm
(.5906 inches) (Fig. 95).
(3) If the measurement exceeds the specification
the secondary timing chains are worn and require
replacement (Refer to 9 - ENGINE/VALVE TIMING/
TIMING BELT/CHAIN AND SPROCKETS -
REMOVAL).
SERVICE PROCEDURE - TIMING VERIFICATION
CAUTION: The 3.7L is a non free-wheeling design
engine. Therefore, correct engine timing is critical.
NOTE: Components referred to as left hand or right
hand are as viewed from the drivers position inside
the vehicle.
NOTE: The blue link plates on the chains and the
dots on the camshaft drive sprockets may not line
up during the timing verification procedure. The
blue link plates are lined up with the sprocket dots
only when re-timing the complete timing drive.
Once the timing drive is rotated blue link-to-dot
alignment is no longer valid.
Engine base timing can be verified by the following
procedure:
(1) Remove the cylinder head covers. Refer to the
procedure in this section.
Fig. 95 Measuring Secondary Timing Chains For
Wear
1 - SECONDARY TENSIONER ARM
2 - SECONDARY CHAIN TENSIONER PISTON
DRENGINE - 3.7L 9 - 77
VALVE TIMING (Continued)

IDLER SHAFT
REMOVAL
(1) Remove the primary and secondary timing
chains and sprockets. Refer to procedure in this sec-
tion.
NOTE: To remove the idler shaft, it is necessary to
tap threads into the shaft, to install the removal
tool.
(2) Using a 12 mm X 1.75 tap, cut threads in the
idler shaft center bore.
(3) Cover the radiator core with a suitable cover.
CAUTION: Use care when removing the idler shaft,
Do not strike the radiator cooling fins with the slide
hammer.
(4) Using Special Tool 8517 Slide Hammer, remove
the idler shaft.
INSTALLATION
(1) Thoroughly clean the idler shaft bore.
(2) Position the idler shaft in the bore.
NOTE: The two lubrication holes in the idler shaft
do not require any special alignment.
NOTE: Before using the retaining bolt to install the
idler shaft, coat the threads and the pilot on the
idler shaft, with clean engine oil.
(3) Using the primary idler sprocket retaining bolt
and washer, carefully draw the idler shaft into the
bore until fully seated.
(4) Coat the idler shaft with clean engine oil.
(5) Install the timing chains and sprockets. Refer
to procedure in this section.
TIMING BELT / CHAIN
COVER(S)
REMOVAL
(1) Disconnect the battery negative cable.
(2) Drain cooling system (Refer to 7 - COOLING -
STANDARD PROCEDURE).
(3) Remove electric cooling fan and fan shroud
assembly.
(4) Remove fan and fan drive assembly (Refer to 7
- COOLING/ENGINE/FAN DRIVE VISCOUS
CLUTCH - REMOVAL).
(5) Disconnect both heater hoses at timing cover.
(6) Disconnect lower radiator hose at engine.(7) Remove accessory drive belt tensioner assembly
(Fig. 103).
(8) Remove crankshaft damper (Refer to 9 -
ENGINE/ENGINE BLOCK/VIBRATION DAMPER -
REMOVAL).
(9) Remove the generator (Refer to 8 - ELECTRI-
CAL/CHARGING/GENERATOR - REMOVAL).
(10) Remove A/C compressor (Refer to 24 - HEAT-
ING & AIR CONDITIONING/PLUMBING/A/C COM-
PRESSOR - REMOVAL).
CAUTION: The 3.7L engine uses an anerobic sealer
instead of a gasket to seal the front cover to the
engine block, from the factory. For service, MoparT
Engine RTV sealant must be substituted.
NOTE: It is not necessary to remove the water
pump for timing cover removal.
(11) Remove the bolts holding the timing cover to
engine block (Fig. 104).
(12) Remove the timing cover.
INSTALLATION
CAUTION: Do not use oil based liquids to clean tim-
ing cover or block surfaces. Use only rubbing alco-
hol, along with plastic or wooden scrapers. Use no
wire brushes or abrasive wheels or metal scrapers,
or damage to surfaces could result.
Fig. 103 ACCESSORY DRIVE BELT TENSIONER
1 - TENSIONER ASSEMBLY
2 - FASTENER TENSIONER TO FRONT COVER
DRENGINE - 3.7L 9 - 81

(1) Clean timing chain cover and block surface
using rubbing alcohol.
CAUTION: The 3.7L uses a special anerobic sealer
instead of a gasket to seal the timing cover to the
engine block, from the factory. For service repairs,
MoparTEngine RTV must be used as a substitute.
(2) Inspect the water passage o-rings for any dam-
age, and replace as necessary.
(3) Apply MopartEngine RTV sealer to front cover
following the path below usinga3to4mmthick
bead (Fig. 105).
(4) Install cover. Tighten fasteners in sequence as
shown in to 58 N´m (43 ft. lbs.) (Fig. 106).
(5) Install crankshaft damper (Refer to 9 -
ENGINE/ENGINE BLOCK/VIBRATION DAMPER -
INSTALLATION).
(6) Install the A/C compressor (Refer to 24 - HEAT-
ING & AIR CONDITIONING/PLUMBING/A/C COM-
PRESSOR - INSTALLATION).
(7) Install the generator (Refer to 8 - ELECTRI-
CAL/CHARGING/GENERATOR - INSTALLATION).
(8) Install accessory drive belt tensioner assembly
(Refer to 7 - COOLING/ACCESSORY DRIVE/BELT
TENSIONERS - INSTALLATION).
(9) Install radiator upper and lower hoses.
(10) Install both heater hoses.
(11) Install electric fan shroud and viscous fan
drive assembly (Refer to 7 - COOLING/ENGINE/FAN
DRIVE VISCOUS CLUTCH - INSTALLATION).
(12) Fill cooling system (Refer to 7 - COOLING -
STANDARD PROCEDURE).
(13) Connect the battery negative cable.
Fig. 104 TIMING CHAIN COVER FASTENERS
Fig. 105 TIMING COVER SEALANT
1 - TIMING CHAIN COVER
2 - WATER PASSAGE ORING
3 - MOPARTENGINE RTV SEALER
Fig. 106 TIMING CHAIN COVER FASTENERS
9 - 82 ENGINE - 3.7LDR
TIMING BELT / CHAIN COVER(S) (Continued)

TIMING BELT/CHAIN AND
SPROCKETS
REMOVAL
(1) Disconnect negative cable from battery.
(2) Drain cooling system(Refer to 7 - COOLING -
STANDARD PROCEDURE).
(3) Remove right and left cylinder head covers(Re-
fer to 9 - ENGINE/CYLINDER HEAD/CYLINDER
HEAD COVER(S) - REMOVAL).
(4) Remove radiator fan shroud(Refer to 7 - COOL-
ING/ENGINE/RADIATOR FAN - REMOVAL).
(5) Rotate engine until timing mark on crankshaft
damper aligns with TDC mark on timing chain cover
(Fig. 108) and the camshaft sprocket ªV6º marks are
at the 12 o'clock position (No. 1 TDC exhaust stroke)
(Fig. 107).
(6) Remove power steering pump(Refer to 19 -
STEERING/PUMP - REMOVAL).
Fig. 107 CAMSHAFT SPROCKET V6 MARKS, (#1 TDC EXHAUST STROKE)
1 - LEFT CYLINDER HEAD2 - RIGHT CYLINDER HEAD
Fig. 108 Engine Top Dead Center
1 - TIMING CHAIN COVER
2 - CRANKSHAFT TIMING MARKS
DRENGINE - 3.7L 9 - 83

(7) Remove access plug from left and right cylinder
heads for access to chain guide fasteners (Fig. 109).
(8) Remove the oil fill housing to gain access to the
right side tensioner arm fastener.
(9) Remove crankshaft damper (Refer to 9 -
ENGINE/ENGINE BLOCK/VIBRATION DAMPER -
REMOVAL) and timing chain cover(Refer to 9 -
ENGINE/VALVE TIMING/TIMING BELT / CHAIN
COVER(S) - REMOVAL).
(10) Collapse and pin primary chain tensioner.
CAUTION: Plate behind left secondary chain ten-
sioner could fall into oil pan. Therefore, cover pan
opening.
(11) Remove secondary chain tensioners.
(12) Remove camshaft position sensor (Fig. 110).
CAUTION: Care should be taken not to damage
camshaft target wheel. Do not hold target wheel
while loosening or tightening camshaft sprocket.
Do not place the target wheel near a magnetic
source of any kind. A damaged or magnetized tar-
get wheel could cause a vehicle no start condition.
CAUTION: Do not forcefully rotate the camshafts or
crankshaft independently of each other. Damaging
intake valve to piston contact will occur. Ensure
negative battery cable is disconnected to guard
against accidental starter engagement.
(13) Remove left and right camshaft sprocket bolts.
(14) While holding the left camshaft steel tube
with Special Tool 8428 Camshaft Wrench, remove the
left camshaft sprocket. Slowly rotate the camshaft
approximately 5 degrees clockwise to a neutral posi-
tion.(15) While holding the right camshaft steel tube
with Special Tool 8428 Camshaft Wrench, remove the
right camshaft sprocket.
(16) Remove idler sprocket assembly bolt.
(17) Slide the idler sprocket assembly and crank
sprocket forward simultaneously to remove the pri-
mary and secondary chains.
(18) Remove both pivoting tensioner arms and
chain guides.
(19) Remove primary chain tensioner.
INSPECTION
Inspect the following components:
²Sprockets for excessive tooth wear. Some tooth
markings are normal and not a cause for sprocket
replacement.
²Idler sprocket assembly bushing and shaft for
excessive wear.
²Idler sprocket assembly spline joint. The joint
should be tight with no backlash or axial movement.
²Chain guides and tensioner arms. Replace these
parts if grooving in plastic face is more than 1 mm
(0.039 in.) deep. If plastic face is severely grooved or
melted, the tensioner lube jet may be clogged. The
tensioner should be replaced.
²Secondary chain tensioner piston and ratcheting
device. Inspect for evidence of heavy contact between
tensioner piston and tensioner arm. If this condition
exist the tensioner tensioner arm and chain should
be replaced.
Fig. 109 Cylinder Head Access Plugs
1 - RIGHT CYLINDER HEAD ACCESS PLUG
2 - LEFT CYLINDER HEAD ACCESS PLUG
Fig. 110 Camshaft Position Sensor
1 - CYLINDER HEAD
2 - CAMSAHFT POSITION SENSOR
3 - SCREW
9 - 84 ENGINE - 3.7LDR
TIMING BELT/CHAIN AND SPROCKETS (Continued)

²Primary chain tensioner plastic faces. Replace as
required.
INSTALLATION
(1) Using a vise, lightly compress the secondary
chain tensioner piston until the piston step is flush
with the tensioner body. Using a pin or suitable tool,
release ratchet pawl by pulling pawl back against
spring force through access hole on side of tensioner.
While continuing to hold pawl back, Push ratchet
device to approximately 2 mm from the tensioner
body. Install Special Tool 8514 lock pin into hole on
front of tensioner (Fig. 111). Slowly open vise to
transfer piston spring force to lock pin.
(2) Position primary chain tensioner over oil pump
and insert bolts into lower two holes on tensioner
bracket. Tighten bolts to 28 N´m (250 in. lbs.).
(3) Install right side chain tensioner arm. Install
Torxtbolt. Tighten Torxtbolt to 28 N´m (250 in.
lbs.).
CAUTION: The silver bolts retain the guides to the
cylinder heads and the black bolts retain the guides
to the engine block.
(4) Install the left side chain guide. Tighten the
bolts to 28 N´m (250 in. lbs.).(5) Install left side chain tensioner arm, and Torxt
bolt. Tighten Torxtbolt to 28 N´m (250 in. lbs.).
(6) Install the right side chain guide. Tighten the
bolts to 28 N´m (250 in. lbs.).
(7) Install both secondary chains onto the idler
sprocket. Align two plated links on the secondary
chains to be visible through the two lower openings
on the idler sprocket (4 o'clock and 8 o'clock). Once
the secondary timing chains are installed, position
special tool 8429 to hold chains in place for installa-
tion.
(8) Align primary chain double plated links with
the timing mark at 12 o'clock on the idler sprocket.
Align the primary chain single plated link with the
timing mark at 6 o'clock on the crankshaft sprocket.
(9) Lubricate idler shaft and bushings with clean
engine oil.
NOTE: The idler sprocket must be timed to the
counterbalance shaft drive gear before the idler
sprocket is fully seated.
(10) Install all chains, crankshaft sprocket, and
idler sprocket as an assembly (Fig. 112). After guid-
ing both secondary chains through the block and cyl-
inder head openings, affix chains with a elastic strap
or equivalent. This will maintain tension on chains to
aid in installation. Align the timing mark on the
idler sprocket gear to the timing mark on the coun-
terbalance shaft drive gear, then seat idler sprocket
fully (Fig. 113). Before installing idler sprocket bolt,
lubricate washer with oil, and tighten idler sprocket
assembly retaining bolt to 34 N´m (25 ft. lbs.).
Fig. 111 RESETTING SECONDARY CHAIN
TENSIONERS
1 - VISE
2 - INSERT LOCK PIN
3 - RATCHET PAWL
4 - RATCHET
5 - PISTON
Fig. 112 INSTALLING IDLER GEAR, PRIMARY AND
SECONDARY TIMING CHAINS
1 - SPECIAL TOOL 8515
2 - PRIMARY CHAIN IDLER SPROCKET
3 - CRANKSHAFT SPROCKET
DRENGINE - 3.7L 9 - 85
TIMING BELT/CHAIN AND SPROCKETS (Continued)