1998 DODGE RAM 1500 Fig

INSTALLATION
NOTE: The cylinder head bolts are tightened using
a torque plus angle procedure. The bolts must be
examined BEFORE reuse. If the threads are necked
down the bolts should be replaced.
Necking can be checked by holding a straight edge
against the threads (Fig. 24). If all the threads do not
contact the scale, the bolt should be replaced.
CAUTION: When cleaning cylinder head and cylin-
der block surfaces, DO NOT use a metal scraper
because the surfaces could be cut or ground. Use
only a wooden or plastic scraper.
(1) Clean the cylinder head and cylinder block
mating surfaces (Fig. 25).
(2) Position the new cylinder head gasket on the
locating dowels.
CAUTION: When installing cylinder head, use care
not damage the tensioner arm or the guide arm.
(3) Position the cylinder head onto the cylinder
block. Make sure the cylinder head seats fully over
the locating dowels.
NOTE: The four M8 cylinder head mounting bolts
require sealant to be added to them before install-
ing. Failure to do so may cause leaks.
(4) Lubricate the cylinder head bolt threads with
clean engine oil and install the eight M10 bolts.
(5)
Coat the four M8 cylinder head bolts withMopar
Lock and Seal Adhesive
then install the bolts.
NOTE: The cylinder head bolts are tightened using
an angle torque procedure, however, the bolts are
not a torque-to-yield design.(6) Tighten the bolts in sequence using the follow-
ing steps and torque values:
²Step 1: Tighten bolts 1-8, 27 N´m (20 ft. lbs.).
²Step 2: Verify that bolts 1-8, all reached 27 N´m
(20 ft. lbs.), by repeating step 1 without loosening the
bolts. Tighten bolts 9 thru 12 to 14 N´m (10 ft. lbs.).
²Step 3: Tighten bolts 1-8, 90 É (Fig. 26).
²Step 4: Tighten bolts 1-8, 90 É, again. Tighten
bolts 9-12, 26 N´m (19 ft. lbs.)
Fig. 24 Checking Cylinder Head Bolts for Stretching
(Necking)
1 - STRETCHED BOLT
2 - THREADS ARE NOT STRAIGHT ON LINE
3 - THREADS ARE STRAIGHT ON LINE
4 - UNSTRETCHED BOLT
Fig. 25 Proper Tool Usage For Surface Preparation
1 - PLASTIC/WOOD SCRAPER
Fig. 26 Cylinder Head Tightening Sequence
* - INDICATES SEALANT ON THREADS
9 - 34 ENGINE - 3.7LDR
CYLINDER HEAD - RIGHT (Continued)

(5) Position Special Tool 8379 timing chain wedge
between the timing chain strands. Tap the tool to
securely wedge the timing chain against the ten-
sioner arm and guide.
(6) Remove the camshaft position sensor.
(7) Hold the camshaft with Special Tool 8428 Cam-
shaft Wrench, while removing the camshaft sprocket
bolt and sprocket.
(8) Starting at the outside working inward, loosen
the camshaft bearing cap retaining bolts 1/2 turn at
a time. Repeat until all load is off the bearing caps.
CAUTION: DO NOT STAMP OR STRIKE THE CAM-
SHAFT BEARING CAPS. SEVERE DAMAGE WILL
OCCUR TO THE BEARING CAPS.
NOTE: When the camshaft is removed the rocker
arms may slide downward, mark the rocker arms
before removing camshaft.
(9) Remove the camshaft bearing caps and the
camshaft.
INSTALLATION
(1) Lubricate camshaft journals with clean engine
oil.
NOTE: Position the right side camshaft so that the
camshaft sprocket dowel is near the 10 o'clock
position, This will place the camshaft at the neutral
position easing the installation of the camshaft
bearing caps.
(2) Position the camshaft into the cylinder head.
(3) Install the camshaft bearing caps, hand tighten
the retaining bolts.
NOTE: Caps should be installed so that the
stamped numbers on the caps are in numerical
order, ( 1 thru 4 ) from the front to the rear of the
engine. All caps should be installed so that the
stamped arrows on the caps point toward the front
of the engine.
(4) Working in 1/2 turn increments, tighten the
bearing cap retaining bolts starting with the middle
cap working outward (Fig. 27).
(5) Torque the camshaft bearing cap retaining
bolts to 11 N´m (100 in. lbs.).(6) Position the camshaft drive gear into the tim-
ing chain aligning the V6 mark between the two
marked chain links (Two links marked during
removal).
(7) Using Special Tool 8428 Camshaft Wrench,
rotate the camshaft until the camshaft sprocket
dowel is aligned with the slot in the camshaft
sprocket . Install the sprocket onto the camshaft.
CAUTION: Remove excess oil from camshaft
sprocket bolt. Failure to do so can cause bolt over-
torque resulting in bolt failure.
(8) Remove excess oil from camshaft sprocket bolt,
then install the camshaft sprocket retaining bolt and
hand tighten.
(9) Remove timing chain wedge special tool 8379.
(10) Using Special Tool 6958 spanner wrench with
adapter pins 8346, torque the camshaft sprocket
retaining bolt to 122 N´m (90 ft. lbs.).
(11) Install the camshaft position sensor.
(12) Install the cylinder head cover(Refer to 9 -
ENGINE/CYLINDER HEAD/CYLINDER HEAD
COVER(S) - INSTALLATION).
Fig. 27 CAMSHAFT BEARING CAPS TIGHTENING
9 - 36 ENGINE - 3.7LDR
CAMSHAFT(S) (Continued)

CYLINDER HEAD COVER(S)
REMOVAL
(1) Disconnect battery negative cable.
(2) Remove air cleaner assembly, resonator assem-
bly and air inlet hose.
(3) Drain cooling system, below the level of the
heater hoses(Refer to 7 - COOLING - STANDARD
PROCEDURE).
(4)
Remove accessory drive belt(Refer to 7 - COOL-
ING/ACCESSORY DRIVE/DRIVE BELTS - REMOVAL).
(5) Remove air conditioning compressor retaining
bolts and move compressor to the left.
(6) Remove heater hoses.
(7) Disconnect injector and ignition coil connectors.
(8) Disconnect and remove positive crankcase ven-
tilation (PCV) hose.
(9) Remove oil fill tube.
(10) Un-clip injector and ignition coil harness and
move away from cylinder head cover.
(11) Remove right rear breather tube and filter
assembly.
(12) Remove cylinder head cover retaining bolts.
(13) Remove cylinder head cover.
INSTALLATION
CAUTION: Do not use harsh cleaners to clean the
cylinder head covers. Severe damage to covers
may occur.
NOTE: The gasket may be used again, provided no
cuts, tears, or deformation has occurred.
(1) Clean cylinder head cover and both sealing sur-
faces. Inspect and replace gasket as necessary.
(2) Tighten cylinder head cover bolts and double
ended studs to 12 N´m (105 in. lbs).
(3) Install right rear breather tube and filter
assembly.
(4) Connect injector, ignition coil electrical connec-
tors and harness retaining clips.
(5) Install the oil fill tube.
(6) Install PCV hose.
(7) Install heater hoses.
(8) Install air conditioning compressor retaining
bolts.
(9) Install accessory drive belt(Refer to 7 - COOL-
ING/ACCESSORY DRIVE/DRIVE BELTS - INSTAL-
LATION).
(10) Fill Cooling system(Refer to 7 - COOLING -
STANDARD PROCEDURE).
(11) Install air cleaner assembly, resonator assem-
bly and air inlet hose.
(12) Connect battery negative cable.
ROCKER ARM
DESCRIPTION
The rocker arms are steel stampings with an inte-
gral roller bearing. The rocker arms incorporate a 2.8
mm (0.11 inch) oil hole in the lash adjuster socket for
roller and camshaft lubrication.
REMOVAL
NOTE: Disconnect the battery negative cable to pre-
vent accidental starter engagement.
(1) Remove the cylinder head cover (Refer to 9 -
ENGINE/CYLINDER HEAD/CYLINDER HEAD
COVER(S) - REMOVAL).
(2) For rocker arm removal on cylinder No. 4,
Rotate the crankshaft until cylinder No. 1 is at BDC
intake stroke.
(3) For rocker arm removal on cylinder No. 1,
Rotate the crankshaft until cylinder No. 1 is at BDC
combustion stroke.
(4) For rocker arm removal on cylinders No. 3 and
No. 5, Rotate the crankshaft until cylinder No. 1 is at
TDC exhaust stroke.
(5) For rocker arm removal on cylinders No. 2 and
No. 6, Rotate the crankshaft until cylinder No. 1 is at
TDC ignition stroke.
(6) Using special tool 8516 Rocker Arm Remover,
press downward on the valve spring, remove rocker
arm (Fig. 28).
Fig. 28 Rocker Arm - Removal
1 - CAMSHAFT
2 - SPECIAL TOOL 8516
DRENGINE - 3.7L 9 - 37

for this job. In addition to deglazing, it will reduce
taper and out-of-round, as well as removing light
scuffing, scoring and scratches. Usually, a few strokes
will clean up a bore and maintain the required lim-
its.
CAUTION: DO NOT use rigid type hones to remove
cylinder wall glaze.
(2) Deglazing of the cylinder walls may be done if
the cylinder bore is straight and round. Use a cylin-
der surfacing hone, Honing Tool C-3501, equipped
with 280 grit stones (C-3501-3810). about 20-60
strokes, depending on the bore condition, will be suf-
ficient to provide a satisfactory surface. Using honing
oil C-3501-3880, or a light honing oil, available from
major oil distributors.
CAUTION: DO NOT use engine or transmission oil,
mineral spirits, or kerosene.
(3) Honing should be done by moving the hone up
and down fast enough to get a crosshatch pattern.
The hone marks should INTERSECT at 50É to 60É
for proper seating of rings (Fig. 29).
(4) A controlled hone motor speed between 200 and
300 RPM is necessary to obtain the proper cross-
hatch angle. The number of up and down strokes per
minute can be regulated to get the desired 50É to 60É
angle. Faster up and down strokes increase the cross-
hatch angle.(5) After honing, it is necessary that the block be
cleaned to remove all traces of abrasive. Use a brush
to wash parts with a solution of hot water and deter-
gent. Dry parts thoroughly. Use a clean, white, lint-
free cloth to check that the bore is clean. Oil the
bores after cleaning to prevent rusting.
CLEANING
Thoroughly clean the oil pan and engine block gas-
ket surfaces.
Use compressed air to clean out:
²The galley at the oil filter adaptor hole.
²The front and rear oil galley holes.
²The feed holes for the crankshaft main bearings.
Once the block has been completely cleaned, apply
Loctite PST pipe sealant with Teflon 592 to the
threads of the front and rear oil galley plugs. Tighten
the 1/4 inch NPT plugs to 20 N´m (177 in. lbs.)
torque. Tighten the 3/8 inch NPT plugs to 27 N´m
(240 in. lbs.) torque.
INSPECTION
(1) It is mandatory to use a dial bore gauge to
measure each cylinder bore diameter. To correctly
select the proper size piston, a cylinder bore gauge,
capable of reading in 0.003 mm (.0001 in.) INCRE-
MENTS is required. If a bore gauge is not available,
do not use an inside micrometer (Fig. 30).
Fig. 29 CYLINDER BORE CROSSHATCH PATTERN
1 - CROSSHATCH PATTERN
2 - INTERSECT ANGLE
Fig. 30 BORE GAUGE-TYPICAL
1 - FRONT
2 - BORE GAUGE
3 - CYLINDER BORE
4 - 38 MM (1.5 in)
DRENGINE - 3.7L 9 - 39
ENGINE BLOCK (Continued)

(2) Measure the inside diameter of the cylinder
bore at three levels below top of bore. Start perpen-
dicular (across or at 90 degrees) to the axis of the
crankshaft and then take two additional reading.
(3) Measure the cylinder bore diameter crosswise
to the cylinder block near the top of the bore. Repeat
the measurement near the middle of the bore, then
repeat the measurement near the bottom of the bore.
(4) Determine taper by subtracting the smaller
diameter from the larger diameter.
(5) Rotate measuring device 90É and repeat steps
above.
(6) Determine out-of-roundness by comparing the
difference between each measurement.
(7) If cylinder bore taper does not exceed 0.025
mm (0.001 inch) and out-of-roundness does not
exceed 0.025 mm (0.001 inch), the cylinder bore can
be honed. If the cylinder bore taper or out- of-round
condition exceeds these maximum limits, the cylinder
block must be replaced. A slight amount of taper
always exists in the cylinder bore after the engine
has been in use for a period of time.
CRANKSHAFT
DESCRIPTION
The crankshaft is constructed of nodular cast iron.
The crankshaft is a three throw split pin design with
six counterweights for balancing purposes. The
crankshaft is supported by four select fit main bear-
ings with the No. 2 serving as the thrust washer
location. The main journals of the crankshaft are
cross drilled to improve rod bearing lubrication. The
No. 6 counterweight has provisions for crankshaft
position sensor target wheel mounting. The select fit
main bearing markings are located on the rear side
of the target wheel (Fig. 31). The crankshaft oil seals
are one piece design. The front oil seal is retained in
the timing chain cover, and the rear seal is pressed
in to a bore formed by the cylinder block and the
bedplate assembly.
REMOVAL
NOTE: To remove the crankshaft from the engine,
the engine must be removed from the vehicle.
(1) Remove the engine(Refer to 9 - ENGINE -
REMOVAL).
(2) Remove the engine oil pump(Refer to 9 -
ENGINE/LUBRICATION/OIL PUMP - REMOVAL).CAUTION: DO NOT pry on the oil pan gasket when
removing the oil pan, The oil pan gasket is mounted
to the cylinder block in three locations and will
remain attached to block when removing oil pan.
Gasket can not be removed with oil pan.
(3) Remove the bedplate mounting bolts. Note the
location of the two stud bolts for installation.
(4) Remove the connecting rods from the crank-
shaft.
CAUTION: The bedplate to cylinder block mating
surface is a critical sealing surface. Do not pry on
or damage this surface in anyway.
NOTE: The bedplate contains the lower main bear-
ing halves. Use care when handling bedplate as not
to drop or damage bearing halves. Installing main
bearing halves in the wrong position will cause
severe damage to the crankshaft.
Fig. 31 CRANKSHAFT AND TARGET RING
1 - CRANKSHAFT
2 - CRANKSHAFT POSITION SENSOR TARGET RING
9 - 40 ENGINE - 3.7LDR
ENGINE BLOCK (Continued)

NOTE: The bedplate has pry points cast into it. Use
these points only. The pry points are shown below.
(5) Carefully pry on the pry points (Fig. 32) to
loosen the bedplate then remove the bedplate.
CAUTION: When removing the crankshaft, use care
not to damage bearing surfaces on the crankshaft.
(6) Remove the crankshaft.
(7) Remove the crankshaft tone wheel.
INSPECTION
NOTE: Thoroughly inspect the connecting rod bear-
ing bores and main bearing bores for scoring, blue-
ing or severe scratches. Further disassembly may
be required.If connecting rod bearing bores show damage, the
cylinder heads must be removed to service the piston
and rod assemblies. If the bedplate or the cylinder
block main bearing bores show damage the engine
must be replaced.
(1) If required, remove the main bearing halves
from the cylinder block and bedplate.
(2) Thoroughly clean the bedplate to cylinder block
sealing surfaces and main bearing bores. Remove all
oil and sealant residue.
(3) Inspect the bedplate main bearing bores for
cracks, scoring or severe blueing. If either condition
exists the engine must be replaced.
(4) Inspect the crankshaft thrust washers for scor-
ing, scratches, wear or blueing. If either condition
exist replace the thrust washers.
(5) Inspect the oil pan gasket/windage tray for
splits, tears or cracks in the gasket sealing surfaces.
Replace gasket as necessary.
Fig. 32 BEDPLATE PRY POINT LOCATION
DRENGINE - 3.7L 9 - 41
CRANKSHAFT (Continued)

INSTALLATION
CAUTION: Main bearings are select fit. Refer to
Crankshaft Main Bearings in this section for proper
bearing selections.
CAUTION: When installing crankshaft, use care not
to damage bearing surfaces on the crankshaft.
NOTE: Apply sealant to the tone wheel retaining
screws prior to installation.
(1) Lubricate upper main bearing halves with
clean engine oil.
(2) Install the crankshaft tone wheel. Torque the
mounting screws to 15 N´m (11 ft. lbs.).
(3) Position crankshaft in cylinder block.
(4) Install the thrust washers (Fig. 33).
CAUTION: The bedplate to cylinder block mating
surface must be coated with MoparTEngine RTVsealant prior to installation. Failure to do so will
cause severe oil leaks.
NOTE:Make sure that the bedplate and cylinder block
sealing surfaces are clean and free of oil or other con-
taminants. Contaminants on the sealing surfaces may
cause main bearing distortion and/or oil leaks.
(5) Apply a 2.5mm (0.100 inch) bead of Mopart
Engine RTV sealant to the cylinder block-to-bedplate
mating surface as shown (Fig. 34).
(6) Coat the crankshaft main bearing journals
with clean engine oil and position the bedplate onto
the cylinder block.
Fig. 33 Crankshaft Thrust Washer Installation
1 - CRANKSHAFT THRUST WASHER
Fig. 34 BEDPLATE SEALANT
1 - CYLINDER BLOCK
2 - SEALENT
3 - SEALANT
9 - 42 ENGINE - 3.7LDR
CRANKSHAFT (Continued)

NOTE: Lubricate the bedplate retaining bolts with
clean engine oil prior to installation.
(7) Install the bedplate retaining bolts, making
sure to place the stud bolts in the correct location,
Torque the bolts in the sequence shown (Fig. 35).
²Hand tighten bolts1D,1G and 1Funtil the bed-
plate contacts the block.
²Tighten bolts1A - 1Jto 54 N´m (40 ft. lbs.)
²Tighten bolts1-8to 7 N´m (5 ft. lbs.)
²Turn bolts1-8an additional 90É.
²Tighten boltsA- E27 N´m ( 20 ft. lbs.).(8) Measure crankshaft end play.
(9)
Install the connecting rods and measure side clear-
ance(Refer to 9 - ENGINE/ENGINE BLOCK/PISTON &
CONNECTING ROD - STANDARD PROCEDURE).
(10) Install oil pump(Refer to 9 - ENGINE/LUBRI-
CATION/OIL PUMP - INSTALLATION).
(11) Install the engine(Refer to 9 - ENGINE -
INSTALLATION).
Fig. 35 BEDPLATE TIGHTENING SEQUENCE
DRENGINE - 3.7L 9 - 43
CRANKSHAFT (Continued)