1998 DODGE RAM 1500 Intake

(15) Remove the two charge air cooler mounting
bolts.
(16) Remove charge air cooler (and A/C condenser
if equipped) from vehicle.
(17) Remove accessory drive belt (Refer to 7 -
COOLING/ACCESSORY DRIVE/DRIVE BELTS -
REMOVAL).
(18) Remove accessory drive belt tensioner.
(19) Remove the fan support/hub assembly.
(20) Remove crankshaft damper and speed indica-
tor ring (Refer to 9 - ENGINE/ENGINE BLOCK/VI-
BRATION DAMPER - REMOVAL).
(21) Remove the gear cover-to-housing bolts and
gently pry the cover away from the housing, taking
care not to mar the sealing surfaces. Remove dust
seal with cover.
(22) Using Special Tool 7471±B Crankshaft Bar-
ring Tool, rotate the crankshaft to align the timing
marks on the crankshaft and the camshaft gears.
(23) Remove the cylinder head cover (Refer to 9 -
ENGINE/CYLINDER HEAD/CYLINDER HEAD
COVER(S) - REMOVAL).
(24) Remove the rocker arms, cross heads, and
push rods (Fig. 55). Mark each component so they
can be installed in their original positions.
NOTE: The #5 cylinder intake and the #6 cylinder
intake and exhaust pushrods are removed by lifting
them up and through the provided cowl panel
access holes. Remove the rubber plugs to expose
these relief holes.
(25) Raise the tappets as follows, using the wooden
dowel rods (Fig. 57)provided with the Miller Tool Kit
8502.
(a) Insert the slotted end of the dowel rod into
the tappet.The dowel rods for the rear two
cylinders will have to be cut for cowl panel
clearance.Press firmly to ensure that it is seated
in the tappet.(b) Raise the dowel rod to bring the tappet to
the top of its travel, and wrap a rubber band
around the dowel rods (Fig. 57) to prevent the tap-
pets from dropping into the crankcase.
(c) Repeat this procedure for the remaining cyl-
inders.
(26) Verify that the camshaft timing marks are
aligned with the crankshaft mark (Fig. 56).
(27) Remove the bolts from the thrust plate.
(28) Remove engine mount through bolts.
(29) Install engine support fixture special tool #
8534,and steel bracket/wing nut special tool #
8534A.
(30) Raise engine enough to allow camshaft
removal.
(31) Remove the camshaft, gear and thrust plate.
Fig. 55 Push Rod Removal/Installation
Fig. 56 Timing Mark Alignment
Fig. 57 Use Wooden Dowel Rods to Secure Tappets
in Place - Typical
DRENGINE 5.9L DIESEL 9 - 269
CAMSHAFT & BEARINGS (IN BLOCK) (Continued)

INSPECTION
Camshaft
(1) Inspect the valve lobes and bearing journals for
cracks, pitting, scoring, or generally excessive wear.
Replace any camshaft that exceeds the allowable lim-
its.
(2) Measure the bearing journals and lobes (Fig.
58).
CAUTION: If Camshaft lobes are worn, requiring
camshaft replacement, it is necessary to replace the
tappets also. (Refer to 9 - ENGINE/ENGINE BLOCK/
SOLID LIFTERS - REMOVAL).
CAMSHAFT DIMENSIONS
CAMSHAFT DIMENSIONS
Journal diameter (No.1 and No.7)
Min. 54.028 mm.
(2.127 in.)
Max. 54.048 mm.
(2.128 in.)
Journal diameter (No.2 through
No.6)
Min. 53.962 mm.
(2.1245 in.)
Max. 54.013 mm.
(2.1265 in.)
Diameter of peak of lobe
Intake
Min. 47.175 mm
(1.857 in.)
Max 47.855 mm.
Exhaust
Min. 45.632 mm.
(1.797 in.)
Max. 46.312 mm.
(1.823 in.)
Camshaft Bushing/Bores
Camshaft bores No. 2±6do notuse a bushing.
(1) Inspect the camshaft bushing and bores for
signs of excessive wear.
(2) Measure the camshaft bushing and bores (Fig.
59) with a telescoping bore gauge and micrometer. If
out of specification, (Refer to 9 - ENGINE/ENGINE
BLOCK/CAMSHAFT & BEARINGS (IN BLOCK) -
REMOVAL).
Fig. 59 Measuring Camshaft Bushing and Bores
Fig. 58 Measuring
1 - VALVE LOBE
2 - CAMSHAFT JOURNAL
9 - 270 ENGINE 5.9L DIESELDR
CAMSHAFT & BEARINGS (IN BLOCK) (Continued)

(6) Remove the wooden dowel rods and rubber
bands from the tappets.
(7) Lubricate the push rods with engine oil and
install in their original location.Verify that they
are seated in the tappets.
(8) Lubricate the valve tips with engine oil and
install the crossheads in their original locations.
(9) Lubricate the crossheads and push rod sockets
with engine oil and install the rocker arms and ped-
estals in their original locations. Tighten bolts to 36
N´m (27 ft. lbs.) torque.
(10)Verify valve lash adjustment (Refer to 9 -
ENGINE/CYLINDER HEAD/INTAKE/EXHAUST
VALVES & SEATS - STANDARD PROCEDURE).
(11) Install the cylinder head cover and reusable
gasket (Refer to 9 - ENGINE/CYLINDER HEAD/
CYLINDER HEAD COVER(S) - INSTALLATION).
(12) Install gear housing cover (Refer to 9 -
ENGINE/VALVE TIMING/GEAR HOUSING COVER
- INSTALLATION). Install front crankshaft dust
seal.
(13) Install the crankshaft damper with the speed
indicator ring (Refer to 9 - ENGINE/ENGINE
BLOCK/VIBRATION DAMPER - INSTALLATION).
(14) Install the fan support/hub assembly Refer to
(Refer to 7 - COOLING/ENGINE/RADIATOR FAN -
INSTALLATION).
(15) Install the power steering pump.
(16) Install accessory drive belt tensioner. Torque
bolt to 43 Nm (32 ft. lbs.).
(17) Install the accessory drive belt (Refer to 7 -
COOLING/ACCESSORY DRIVE/DRIVE BELTS -
INSTALLATION).
(18) Install the charge air cooler (with a/c con-
denser and auxiliary transmission oil cooler, if
equipped) and tighten the mounting bolts to 2 N´m
(17 in. lbs.) torque.
(19) Connect charge air cooler inlet and outlet
pipes. Tighten clamps to 11 N´m (95 in. lbs.) torque.
(20) Install the radiator upper support panel.
(21) Close radiator petcock and lower the radiator
into the engine compartment. Tighten the mounting
bolts to 11 N´m (95 in. lbs.) torque.
(22) Raise vehicle on hoist.
(23) Connect radiator lower hose and install
clamp.
(24) Connect transmission auxiliary oil cooler lines
(if equipped).
(25) Lower vehicle.
(26) Install the fan shroud and tighten the mount-
ing screws to 6 N´m (50 in. lbs.) torque.
(27) Install the electronically controlled viscous
fan/drive assembly. Connect harness connector.(Refer
to 7 - COOLING/ENGINE/RADIATOR FAN -
INSTALLATION).(28) Install the coolant recovery and windshield
washer fluid reservoirs to the fan shroud.
(29) Connect the coolant recovery hose to the radi-
ator filler neck.
(30) Add engine coolant (Refer to 7 - COOLING -
STANDARD PROCEDURE).
(31) Charge A/C system with refrigerant (if A/C
equipped) (Refer to 24 - HEATING & AIR CONDI-
TIONING/PLUMBING - STANDARD PROCEDURE).
(32) Connect the battery negative cables.
(33) Start engine and check for engine oil and cool-
ant leaks.
CONNECTING ROD BEARINGS
STANDARD PROCEDURE - CONNECTING ROD
BEARING AND CRANKSHAFT JOURNAL
CLEARANCE
(1) Measure the connecting rod bore with bearings
removedand the bolts tightened to 100 N´m (73 ft.
lbs.) torque..
(2) Measure the connecting rod bore with the bear-
ingsinstalledand the bolts tightened to 100 N´m
(73 ft. lbs.) torque.
Measure within 20É arc from each side of the part-
ing line. Also measure 90É from parting line.
Record the smallest and largest diameter.
Measure the diameter of the rod journal at the
location shown (Fig. 63). Calculate the average diam-
eter for each side of the journal.
Determine minimum bearing clearance by calculat-
ing the differance between the smallest connecting
rod bore diameter with the bearing installed and the
average diameter for each side of the crankshaft jour-
nal.
Determine the maximum bearing clearance by cal-
culating the difference between the largest connect-
ing rod bore diameter and the average diameter with
the bearing installed for each side of the crankshaft
journal.
DESCRIPTION MEASUREMENT
CONNECTING ROD
BORE, BEARINGS
REMOVEDMIN. 72.99 mm (2.874
in.)
MAX. 73.01 mm (2.875
in.)
CONNECTING ROD
BORE, BEARINGS
INSTALLEDMIN. 69.05 mm (2.719
in.)
MAX. 69.10 mm (2.720
in.)
9 - 272 ENGINE 5.9L DIESELDR
CAMSHAFT & BEARINGS (IN BLOCK) (Continued)

PISTON & CONNECTING ROD
DESCRIPTION
PISTONS
The piston (Fig. 85) is constructed of aluminum
and is gravity cast, free floating design. The piston
incorporates a centrally located high swirl combus-
tion bowl, and utilizes a ªkeystoneº style top com-
pression ring (Fig. 86), and a ªTapered Faceº
intermediate ring (Fig. 86), for superior cylinder wall
scraping. Piston cooling nozzles cool the piston and
pin with engine oil supplied by the crankshaft main
journals. High horsepower pistons are gallery cooled
and utilize J-jet piston cooling nozzles. Pistons are
directional in order to provide clearance to piston
cooling nozzles.
CONNECTING RODS
The connecting rods are a split angle design. They
have a pressed-in-place wrist pin bushing that is
lubricated by piston cooling nozzle oil spray.
Machined connecting rods are no longer used
in the diesel engine. Do not install machined
connecting rods into an engine that has frac-
tured split connecting rods.
Fractured split connecting rods are first manufac-
tured as a single piece and then fractured into two
pieces. Fractured split connecting rods can be identi-
fied by a rough and irregular surface at the connect-
ing rod split face. To properly assemble the rod cap to
the connecting rod, the bearing tangs on the connect-
ing rod and cap must be located on the same side of
the rod. The long end of the connecting rod must be
assembled on the intake or camshaft side of the
engine.
Each matched fractured split connecting rod and
cap is an assembly and are not interchangeable. If a
connecting rod or cap is damaged, the entire assem-
bly must be replaced.
STANDARD PROCEDURE - HEAD GASKET
SELECTION
(1) Measure piston protrusion for all six pistons.
(2) Calculate the average piston protrusion. Maxi-
mum allowable protrusion is 0.516 mm (0.020 inch).
NOTE: There are two different head gaskets avail-
able. One gasket is for Average piston protrusion
less than 0.30 mm (0.011 inch). The other gasket is
for Average piston protrusion greater than 0.30 mm
(0.011 inch)
REMOVAL
(1) Disconnect the battery cables.
(2) Remove the cylinder head (Refer to 9 -
ENGINE/CYLINDER HEAD - REMOVAL).
(3) Remove the oil pan and suction tube (Refer to 9
- ENGINE/LUBRICATION/OIL PAN - REMOVAL).
(4) Remove bolts and the block stiffener.
(5) Using Miller Tool 7471-B crankshaft barring
tool, rotate the crankshaft so all of the pistons are
below TDC.
(6) Before removing the piston(s) from the bore(s):
(a) Remove any carbon ridge formations or
deposits at the top of the bore with a dull scraper
or soft wire brush.
(b) If cylinder bore wear ridges are found, use a
ridge reamer to cut the ridge from the bore. DO
NOT remove more metal than necessary to remove
the ridge.
(7) Remove the J-jet cooling nozzles, if equipped.
Fig. 85 Piston - Typical
Fig. 86 Piston Ring Identification
DRENGINE 5.9L DIESEL 9 - 281

Inspect the piston pin for nicks, gouges and exces-
sive wear. Measure the pin diameter (Fig. 89). The
minimum diameter is 39.990 mm (1.5744 inch), max-
imum 40.003 mm (1.5749 inch). If the diameter is out
of limits, replace the pin.
INSPECTIONÐCONNECTING ROD
Inspect the connecting rod for damage and wear.
The I-Beam section of the connecting rod cannot have
dents or other damage. Damage to this part can
cause stress risers which will progress to breakage.
Measure the connecting rod pin bore (Fig. 90). The
maximum diameter is 40.042 mm (1.5765 inch), min-
imum diameter is 40.019 mm (1.5756 inch). If out of
limits, replace the connecting rod.
INSTALLATION
(1) Lubricate the cylinder bores with clean engine
oil.
(2) Generously lubricate the rings and piston
skirts with clean engine oil.(3) Orientate the rings on the piston (Refer to 9 -
ENGINE/ENGINE BLOCK/PISTON RINGS - STAN-
DARD PROCEDURE).
(4) Compress the rings using a piston ring com-
pressor tool (Fig. 91). If using a strap-type ring com-
pressor, make sure the inside end of the strap does
not hook on a ring gap and break the ring.
(5) Bar the crankshaft so the rod journal for the
piston to be installed is at BDC (Bottom Dead Cen-
ter) - (Fig. 92).
(6) Make sure the front of the piston is oriented
properly according to the marking on the top of the
piston and the connecting rod is oriented properly.
(7) Position the piston and rod assembly into the
cylinder bore with the front of the piston oriented
properly according to the stamping in the top of the
piston. Use care when you install the piston and con-
necting rod so the cylinder bore is not damaged. The
long side of the connecting rod must be installed on
the intake side of the engine.
(8) Push the piston into the bore until the top of
the piston is approximately 50 mm (2 inch) below the
top of the block. Carefully pull the connecting rod
onto the crankshaft journal.
(9) Use clean engine oil to lubricate the threads
and under the heads of the connecting rod bolts.
Fig. 89 Piston Pin Diameter
1 - PISTON PIN
Fig. 90 Connecting Rod Pin Bore
1 - CONNECTING ROD
Fig. 91 Piston Ring Compressor Tool
1 - PISTON RING COMPRESSOR TOOL
Fig. 92 Piston/Rod Assembly at BDC
DRENGINE 5.9L DIESEL 9 - 283
PISTON & CONNECTING ROD (Continued)

(10)For fractured/split type connecting rods,
the long end of the rod must be installed towards the
intake side of the engine.
(a) The connecting rod split/face must face
toward the same side as the piston notch feature
on the skirt. The split face will face toward the
exhaust side of the engine if properly installed.
(11) Install the rod cap and bolts to the connecting
rod. Tighten the connecting rod bolts evenly in 3
steps.
²Tighten the bolts to 30 N´m (22 ft. lbs.) torque.
²Tighten the bolts to 60 N´m (44 ft. lbs.) torque.
²Rotate 60É clockwise.
(12) The crankshaft must rotate freely. Check for
freedom of rotation as the caps are installed. If the
crankshaft does not rotate freely, check the installa-
tion of the rod bearing and the bearing size.
(13) Measure the side clearance between the con-
necting rod and the crankshaft. DO NOT measure
the clearance between the cap and crankshaft.
(14) Install J-jet piston cooling nozzles if equipped.
(15) Install block stiffener. Torque to 43 N´m (32 ft.
lbs.).
(16) Install the suction tube and oil pan (Refer to 9
- ENGINE/LUBRICATION/OIL PAN - INSTALLA-
TION).
(17) Install the cylinder head onto the engine
(Refer to 9 - ENGINE/CYLINDER HEAD - INSTAL-
LATION).
(18) Install a new filter and fill the crankcase with
new engine oil.Prefill the filter with clean oil.
(19) Connect the battery negative cables and start
engine.
PISTON RINGS
STANDARD PROCEDURE - PISTON RING
FITTING
(1) Determine the piston diameter and obtain the
appropriate ring set. The piston rings can be identi-
fied as shown in (Fig. 93).
(2) Position each ring in the cylinder and use a
piston to square it with the bore at a depth of 89.0
mm (3.5 inch) - (Fig. 94).(3) Use a feeler gauge to measure the piston ring
gap.
PISTON RING GAP CHART
TOP RING 0.26 - 0.36 mm(0.010 - 0.014
in.)
INTERMEDIATE
RING0.85-1.15 mm(0.033 - 0.045
in.)
OIL CONTROL
RING0.25-0.55 mm(0.010 - 0.022
in.)
Fig. 93 Piston Ring Identification
Fig. 94 Position of Ring in Cylinder Bore
1 - PISTON
2 - CYLINDER BORE
3 - DEPTH
9 - 284 ENGINE 5.9L DIESELDR
PISTON & CONNECTING ROD (Continued)

LUBRICATION
DESCRIPTION
NOTE: Refer to (Fig. 105) and (Fig. 106) for circuit
illustrations.
A gear driven gerotor type oil pump is mounted
behind the front gear cover in the lower right portion
on the engine.
OPERATION
A gerotor style oil pump draws oil from the crank-
case through the suction tube and delivers it through
the block where it enters the oil cooler cover and
pressure regulator valve. When oil pressure exceeds
517 kPa (75 PSI), the valve opens exposing the dump
port, which routes excess oil back to the oil pump.
At the same time, oil is directed to a cast in pas-
sage in the oil cooler cover, leading to the oil cooler
element. As the oil travels through the element
plates, it is cooled by engine coolant traveling past
the outside of the plates. It is then routed to the oil
filter head and through a full flow oil filter. If a
plugged filter is encountered, the filter by-pass valve
opens, allowing unfiltered oil to lubricate the engine.
This condition can be avoided by frequent oil and fil-
ter changes, per the maintenance schedules found in
the owners manual. The by-pass valve is calibrated
to open when it sees a pressure drop of more than
345 kPa (50 psi) across the oil filter.
The oil filter head then divides the oil between the
engine and the turbocharger. The turbocharger
receives filtered, cooled and pressurized oil through a
supply line from the filter head. The oil lubricates
the turbocharger and returns to the pan by way of a
drain tube connecting the bottom of the turbocharger
to a pressed in tube in the cylinder block.
Oil is then carried across the block to an angle
drilling which intersects the main oil rifle. The main
oil rifle runs the length of the block and delivers oil
to the crankshaft main journals and valve train. Oil
travels to the crankshaft through a series of transfer
drillings (one for each main bearing) and lubricates a
groove in the main bearing upper shell. From there
another drilling feeds the camshaft main journals.The saddle jet piston cooling nozzles are also sup-
plied by the main bearing upper shell. J-jet piston
cooling nozzles are supplied by a separate oil rifle.
Plugs are used in place of saddle jets when J-jets are
used. J-jet hole locations are plugged when saddle jet
cooling nozzles are used. Crankshaft internal cross-
drillings supply oil to the connecting rod journals.
Another series of transfer drillings intersecting the
main oil rifle supply the valve train components. Oil
travels up the drilling, through a hole in the head
gasket, and through a drilling in the cylinder head
(one per cylinder), where it enters the rocker arm
pedestal and is divided between the intake and
exhaust rocker arm. Oil travels up and around the
rocker arm mounting bolt, and lubricates the rocker
shaft by cross drillings that intersect the mounting
bolt hole. Grooves at both ends of the rocker shaft
supply oil through the rocker arm where the oil trav-
els to the push rod and socket balls (Fig. 105) and
(Fig. 106).
DIAGNOSIS AND TESTINGÐENGINE OIL
PRESSURE
(1) Remove the 1/8 npt plug from the top of the oil
filter housing.
(2) Install Oil Pressure Line and Gauge Tool
C-3292 with a suitable adapter.
(3) Start engine and warm to operating tempera-
ture.
(4) Record engine oil pressure and compare with
engine oil pressure chart.
CAUTION: If engine oil pressure is zero at idle, DO
NOT RUN THE ENGINE.
Engine Oil Pressure (MIN)
At Idle 68.9 kPa (10 psi)
At 2500 rpm 206.9 kPa (30 psi)
If minimum engine oil pressure is below these
ranges, (Refer to 9 - ENGINE - DIAGNOSIS AND
TESTING).
(5) Remove oil pressure gauge and install the 1/8
npt plug.
DRENGINE 5.9L DIESEL 9 - 289

(13) Install the cooling fan (Refer to 7 - COOLING/
ENGINE/RADIATOR FAN - INSTALLATION).
(14) Connect battery negative cables.
(15) Start engine and check for oil leaks.
INTAKE MANIFOLD
REMOVAL
(1) Disconnect the battery negative cables.
(2) Remove the charge air cooler outlet tube from
the air inlet housing (Fig. 118).
(3) Remove the engine oil dipstick tube mounting
bolt (Fig. 118).
(4) Remove dipstick support at fuel filter housing.
Position dipstick tube to the side.
(5) Disconnect the air grid heater power cables at
the cable mounting studs.
(6) Disconnect the ground strap at the intake
cover.
(7) Remove the engine wiring harness connections
at the air inlet housing elbow.
(8) Remove the four (4) air inlet housing mounting
bolts and remove the housing from top of the heater
elements.
(9) Remove the intake air grid heater from the
manifold (Fig. 119).
(10) Remove the high pressure fuel lines and fuel
rail (Refer to 14 - FUEL SYSTEM/FUEL DELIVERY/
FUEL LINES - REMOVAL).
(11) Remove APPS bracket from cylinder head to
gain access to front intake manifold cover bolts.
(12) Disconnect manifold air temperature/pressure
sensor connector.
(13) Remove the remaining intake manifold cover-
to-cylinder head bolts.
(14) Remove the intake manifold cover and gasket.
Keep the gasket material and any other material out
of the air intake.
(15) Clean the intake manifold cover and cylinder
head sealing surface.
CLEANING
Clean manifold in solvent and blow dry with com-
pressed air.
Clean cylinder block gasket surfaces using a suit-
able solvent.
The plenum pan rail must be clean and dry (free of
all foreign material).
INSPECTION
Inspect manifold for cracks.
Inspect mating surfaces of manifold for flatness
with a straightedge.
Fig. 118 Charge Air Cooler Air Tube
1 - FRONT WIRING CLIP
2 - GROUND CABLE
3 - TUBE BOLT
4 - ENGINE OIL DIPSTICK TUBE
5 - CLAMPS
6 - AIR TUBE (INT. MAN.-TO-INTERCOOLER)
7 - RUBBER HOSE
8 - AIR INTAKE HOUSING
9 - CABLE BRACKET HOUSING
Fig. 119 Intake Air Grid Heater
1 - INTAKE AIR GRID HEATER
2 - GASKET
DRENGINE 5.9L DIESEL 9 - 297
OIL PUMP (Continued)