Oss DODGE RAM 2003 Service Repair Manual

(4) Lubricate the crossheads and push rod sockets
and install the rocker arms and pedestals in their
original locations. Tighten bolts to 36 N´m (27 ft. lbs.)
torque.
(5)Verify valve lash adjustment (Refer to 9 -
ENGINE/CYLINDER HEAD/INTAKE/EXHAUST
VALVES & SEATS - STANDARD PROCEDURE).
(6) Install cylinder head cover and reusable gasket
(Refer to 9 - ENGINE/CYLINDER HEAD/CYLIN-
DER HEAD COVER(S) - INSTALLATION).
(7) Connect battery negative cables.
ROCKER ARM / ADJUSTER
ASSY
DESCRIPTION
The unique intake and exhaust rocker arms have
their own rocker shafts and are lubricated by pas-
sages intersecting the cylinder block main oil rifle.
Crossheads are used, which allow each rocker arm to
operate two valves.
The solid push rods are hardened at the rocker
arm and tappet contact areas for superior strength
and durability.
REMOVAL
(1) Disconnect the battery negative cables.
(2) Remove cylinder head cover (Refer to 9 -
ENGINE/CYLINDER HEAD/CYLINDER HEAD
COVER(S) - REMOVAL).
(3) Remove the rocker arm/pedestal fasteners (Fig.
36) and remove rocker arm and pedestal from cylin-der head. Mark the arms and pedestals so they can
be installed in their original position.
CAUTION: When removing the rocker arms, the
sockets (Fig. 37) may come loose and fall into the
engine. Make sure they stay with the arm upon
removal/installation.
(4) Lift the push rod(s) up and out of the engine
(Fig. 38). Mark them so they can be installed in their
original position.
NOTE: The #5 cyl. intake and exhaust and #6 cyl.
intake and exhaust push rods must be raised
through the provided cowl panel access holes.
(5) Lift the crosshead(s) off of the valve stems.
Mark them so they can be installed in their original
position.
CLEANING
Clean all components in a suitable solvent. If nec-
essary, use a wire brush or wheel to remove stubborn
deposits. Rinse in hot water and blow dry with com-
pressed air. Inspect oil passages in rocker arms and
pedestals. Apply compressed air to lubrication orifices
to purge contaminants.
Fig. 35 Compressing Valve Springs with Tool
8319±A
1 - SPECIAL TOOL 8319
Fig. 36 Rocker Arm and Pedestal Removal
1 - ROCKER ARM
2 - PEDESTAL
9 - 310 ENGINE 5.9L DIESELDR
INTAKE/EXHAUST VALVES & SEATS (Continued)

Crossheads
Inspect the crossheads for cracks and/or excessive
wear on rocker lever and valve tip mating surfaces
(Fig. 43).
INSTALLATION
(1) If previously removed, install the push rods in
their original location.Verify that they are seated
in the tappets.
(2) Lubricate the valve tips and install the cross-
heads in their original locations.
(3) Lubricate the crossheads and push rod sockets
and install the rocker arms and pedestals in their
original locations. Tighten bolts to 36 N´m (27 ft. lbs.)
torque.
(4)Verify valve lash adjustment (Refer to 9 -
ENGINE/CYLINDER HEAD/INTAKE/EXHAUST
VALVES & SEATS - STANDARD PROCEDURE).
(5) Install cylinder head cover and reusable gasket
(Refer to 9 - ENGINE/CYLINDER HEAD/CYLIN-
DER HEAD COVER(S) - INSTALLATION).
(6) Connect battery negative cables.
ENGINE BLOCK
STANDARD PROCEDURE
STANDARD PROCEDURE - CYLINDER BLOCK
REFACING
(1) The combustion deck can be refaced twice. The
first reface should be 0.25 mm (0.0098 inch). If addi-
tional refacing is required, an additional 0.25 mm
(0.0098 inch) can be removed. Total allowed refacing
is 0.50 mm (0.0197 inch) - (Fig. 44).
(2) The upper right corner of the rear face of the
block must be stamped with a X when the block is
refaced to 0.25 mm (0.0098 inch). A second X must be
stamped beside the first when the block is refaced to
0.50 mm (0.0197 inch) - (Fig. 45).
Fig. 42 Inspecting Push Rod for Flatness
Fig. 43 Inspecting Crosshead for Cracks
Fig. 44 Refacing Dimensions of the Cylinder Block
CYLINDER BLOCK REFACING DIMENSIONS
DIMENSION(A(
1st Reface 0.25mm (0.0098 in.)
2nd Reface 0.25mm (0.0098 in.)
Dim (A) Total 0.50 mm (0.0197 in.)
DIMENSION(B(
Dim.9B9(STD.)323.00 mm   0.10
mm(12.7165 in.  
0.0039 in.)
1st Reface322.75 mm   0.10
mm(12.7067 in.  
0.0039 in.)
2nd Reface322.50 mm   0.10
mm(12.6968 in.  
0.0039 in.)
9 - 312 ENGINE 5.9L DIESELDR
ROCKER ARM / ADJUSTER ASSY (Continued)

(3) Consult the parts catalog for the proper head
gaskets which must be used with refaced blocks to
ensure proper piston-to-valve clearance.
STANDARD PROCEDURE - CYLINDER BORE -
DE-GLAZE
(1) New piston rings may not seat in glazed cylin-
der bores.
(2) De-glazing gives the bore the correct surface
finish required to seat the rings. The size of the bore
is not changed by proper de-glazing.
(3) Cover the lube and tappet holes in the top of
the block with waterproof tape.
(4) It crankshaft is installed, wrap connecting rod
journals with clean cloth. Cover cloth with water-
proof tape.
(5) A correctly honed surface will have a cross-
hatch appearance with the lines at 15É to 25É angles
(Fig. 46). For the rough hone, use 80 grit honing
stones. To finish hone, use 280 grit honing stones.
(6) Use a drill, a fine grit Flex-hone and a mixture
of equal parts of mineral spirits and SAE 30W engine
oil to de-glaze the bores.
(7) The crosshatch angle is a function of drill
speed and how fast the hone is moved vertically (Fig.
47).
(8) Vertical strokes MUST be smooth continuous
passes along the full length of the bore (Fig. 47).(9) Inspect the bore after 10 strokes.
(10) Use a strong solution of hot water and laun-
dry detergent to clean the bores. Clean the cylinder
bores immediately after de-glazing.
(11) Rinse the bores until the detergent is removed
and blow the block dry with compressed air.
(12) Check the bore cleanliness by wiping with a
white, lint free, lightly oiled cloth. If grit residue is
still present, repeat the cleaning process until all res-
idue is removed. Wash the bores and the complete
block assembly with solvent and dry with compressed
air. Place a clean shop towel around the top main
bearing saddle to deflect water and residue from pis-
ton cooling nozzels. Remove directed piston cooling
nozzles if installed.
(13) Be sure to remove the tape covering the lube
holes, rod journals, and piston cooling nozzles after
the cleaning process is complete.
STANDARD PROCEDUREÐCYLINDER BORE
REPAIR
Cylinder bore(s) can be repaired by one of two
methods:
²Method 1:ÐOver boring and using oversize pis-
tons and rings.
²Method 2:ÐBoring and installing a repair sleeve
to return the bore to standard dimensions.
METHOD 1ÐOVERSIZE BORE
Cylinder bore(s) can be repaired by one of two
methods:
Oversize pistons and rings are available in two
sizes - 0.50 mm (0.0197 inch) and 1.00 mm (0.0393
inch).
Any combination of standard, 0.50 mm (0.0197
inch) or 1.00 mm (0.0393 inch) overbore may be used
in the same engine.
Fig. 45 Stamp Block after Reface
Fig. 46 Cylinder Bore Crosshatch Pattern
Fig. 47 De-Glazing Drill Speed and Vertical Speed
DRENGINE 5.9L DIESEL 9 - 313
ENGINE BLOCK (Continued)

If more than 1.00 mm (0.0393 inch) overbore is
needed, a repair sleeve can be installed (refer to
Method 2ÐRepair Sleeve).
Cylinder block bores may be bored twice before use
of a repair sleeve is required. The first bore is 0.50
mm (0.0197 inch) oversize. The second bore is 1.00
mm (0.0393 inch) oversize.
After boring to size, use a honing stone to chamfer
the edge of the bore.
CYLINDER BORE DIMENSION CHART
DESCRIPTION MEASUREMENT
BORING DIAMETER
DIMENSION1st. REBORE - 102.469
mm (4.0342 in.)
2nd. REBORE - 102.969
mm (4.0539 in.)
HONING DIAMETER
DIMENSIONSSTANDARD - 102.020  
0.020 mm (4.0165  
0.0008 in.)
1st. REBORE - 102.520
  0.020 mm (4.0362  
0.0008 in.)
2nd. REBORE - 103.020
  0.020 mm 4.0559  
0.0008 in.)
CHAMFER
DIMENSIONSApprox. 1.25 mm (0.049
in.) by 15É
A correctly honed surface will have a crosshatch
appearance with the lines at 15É to 25É angles with
the top of the cylinder block (Fig. 48). For the rough
hone, use 80 grit honing stones. To finish hone, use
280 grit honing stones.
A maximum of 1.2 micrometer (48 microinch) sur-
face finish must be obtained.
After finish honing is complete, immediately clean
the cylinder bores with a strong solution of laundry
detergent and hot water.
After rinsing, blow the block dry.
Check the bore cleanliness by wiping with a white,
lint-free, lightly- oiled cloth. There should be no grit
residue present.If the block is not to be used right away, coat it
with a rust- preventing compound.
METHOD 2ÐREPAIR SLEEVE
If more than a 1.00 mm (0.03937 inch) diameter
oversize bore is required, the block must be bored
and a repair sleeve installed.
Bore the block cylinder bore to 104.500-104.515
mm (4.1142-4.1148 inch) - (Fig. 49).
Repair sleeves can be replaced by using a boring
bar to bore out the old sleeve. DO NOT cut the cyl-
inder bore beyond the oversize limit.
REPAIR SLEEVE BLOCK REBORE
DIMENSIONS CHART
BORE DIAMETER STEP DIMENSION
104.500 + 0.015 mm
(4.1142 + 0.0006 in.)6.35 mm (0.25 in.)
After machining the block for the new repair
sleeve, thoroughly clean the bore of all metal chips,
debris and oil residue before installing the sleeve.
Cool the repair sleeve(s) to a temperature of -12ÉC
(10ÉF) or below for a minimum of one hour. Be ready
to install the sleeve immediately after removing it
from the freezer.
Apply a coat of Loctite 620, or equivalent to the
bore that is to be sleeved.
Wear protective gloves to push the cold sleeve into
the bore as far as possible.
Fig. 48 Crosshatch Pattern of Repaired Sleeve(s)
Fig. 49 Block Bore for Repair Sleeve Dimensions
1 - BORE DIAMETER
2 - STEP DIMENSION
9 - 314 ENGINE 5.9L DIESELDR
ENGINE BLOCK (Continued)

Using a sleeve driver, drive the sleeve downward
until it contacts the step at the bottom of the bore
(Fig. 50).
A sleeve driver can be constructed as follows (Fig.
51).
SLEEVE DRIVER CONSTRUCTION
SPECIFICATION CHART
ITEM MEASUREMENT
A 127 mm (5 in.)
B 38 mm (1.5 in.)
C 6.35 mm (0.25 in.)
D 25.4 mm (1 in.)
E 101 mm (3.976 in.)
F 107.343 mm (4.226 in.)Set up a boring bar and machine the sleeve to
101.956 mm (4.014 inch).
After removing the boring bar, use a honing stone
to chamfer the corner of the repair sleeve(s).
SLEEVE MACHINING DIMENSIONS CHART
ITEM MEASUREMENT
SLEEVE PROTRUSION MIN. - FLUSH WITH
BLOCK
MAX. - 0.050 mm
(0.0019 in.)
SLEEVE DIAMETER 101.956 mm (4.014 in.)
SLEEVE CHAMFER APPROX. 1.25 mm
(0.049 in.) by 15É
A correctly honed surface will have a crosshatch
appearance with the lines at 15É to 25É angles with
the top of the cylinder block. For the rough hone, use
80 grit honing stones. To finish hone, use 280 grit
honing stones.
Finished bore inside dimension is 102.020  0.020
mm (4.0165  0.0008 inch).
A maximum of 1.2 micrometer (48 microinch) sur-
face finish must be obtained.
After finish honing is complete, immediately clean
the cylinder bores with a strong solution of laundry
detergent and hot water.
After rinsing, blow the block dry with compressed
air.
Wipe the bore with a white, lint-free, lightly oiled
cloth. Make sure there is no grit residue present.
Apply a rust-preventing compound if the block will
not be used immediately.
A standard diameter piston and a piston ring set
must be used with a sleeved cylinder bore.
STANDARD PROCEDUREÐCAM BORE REPAIR
For standard bushings, not oversized, maximum
front and rear cam bushing bore diameter is 59.248
mm. (2.3326 in.). DO NOT bore the intermediate cam
bore to the front cam bore oversize dimensions. Max-
imum front and rear camshaft bushing installed
diameter is 54.147 mm. (2.1318 in.). Minimum
installed diameter is 54.083 mm. (2.1293 in.). Maxi-
mum intermediate camshaft bore diameter is 54.164
mm. (2.1324 in.).
A surface finish of 2.3 micrometers (92 microinch)
must be maintained. Not more than 20% of an area
of any one bore may be 3.2 micrometers (126 micro-
inch).
Camshaft bores can be repaired individually. It is
not necessary to repair undamaged cam bores in
order to repair individually damaged cam bores. The
Fig. 50 Sleeve Installation
1 - SLEEVE DRIVER
2 - SLEEVE
3 - CONTACT
Fig. 51 Sleeve Driver Construction
1 - DRIVE
2 - HANDLE
DRENGINE 5.9L DIESEL 9 - 315
ENGINE BLOCK (Continued)

CAMSHAFT & BEARINGS (IN
BLOCK)
REMOVAL
REMOVALÐCAMSHAFT BEARINGS
NOTE: Measure the diameter of each bore. If the
camshaft bore for the first or rear cam bushing is
worn beyond the limit, install a new service bush-
ing. Inspect the rest of the camshaft bores for dam-
age or excessive wear.If the bores without a
bushing are worn beyond the limit, the engine must
be removed for machining and installation of ser-
vice bushings. If badly worn, replace the cylinder
block.
(1) Remove the camshaft (Refer to 9 - ENGINE/
ENGINE BLOCK/CAMSHAFT & BEARINGS (IN
BLOCK) - REMOVAL).
(2) Remove the bushing from the No.1 bore and
No.7 using a universal cam bushing tool.
(3) Mark the cylinder block so you can align the oil
hole in the cylinder block with the oil hole in the
bushing.
REMOVAL - CAMSHAFT
(1) Disconnect both battery negative cables.
(2) Recover A/C refrigerant (if A/C equipped) (Refer
to 24 - HEATING & AIR CONDITIONING/PLUMB-
ING - STANDARD PROCEDURE).
(3) Raise vehicle on hoist.
(4) Drain engine coolant into container suitable for
re-use (Refer to 7 - COOLING - STANDARD PROCE-
DURE).
(5) Lower vehicle.
(6) Remove radiator upper hose.
(7) Remove viscous fan/drive assembly and fan
shroud (Refer to 7 - COOLING/ENGINE/RADIATOR
FAN - REMOVAL).
(8) Disconnect the coolant recovery bottle hose
from the radiator filler neck.
(9) Disconnect lower radiator hose from radiator
outlet.
(10)Automatic Transmission models:Discon-
nect transmission oil cooler lines from front of radia-
tor using Special Tool 6931 (unless equipped with
finger-release disconnect).
(11) Remove radiator mounting screws and lift
radiator out of engine compartment.
(12) Remove upper radiator support panel.
(13) If A/C equipped, disconnect A/C condenser
refrigerant lines.
(14) Disconnect charge air cooler piping from the
cooler inlet and outlet.(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.
Fig. 55 Push Rod Removal/Installation
DRENGINE 5.9L DIESEL 9 - 317

Thrust Plate
Inspect the camshaft thrust plate for excessive
wear in the camshaft contact area. Measure thrust
plate thickness using the CAMSHAFT THRUST
PLATE THICKNESS CHART. Replace any thrust
plate that falls outside of these specifications:
CAMSHAFT THRUST PLATE THICKNESS CHART
MIN. 9.34 mm (0.368 in.)
MAX. 9.60 mm (0.378 in.)
INSTALLATION
INSTALLATION - CAMSHAFT BEARINGS
(1) Apply a coating of Loctitet640 Adhesive to the
backside of the new bushing. Avoid getting adhesive
in the oil hole.
(2) Use a universal cam bushing installation tool
and install the front bushing so that it is even with
the front face of the cylinder block. The oil hole must
be aligned. A 3.2 mm (0.128 inch) diameter rod must
be able to pass through the hole. (Fig. 63).
(3) Install the rear camshaft bushing is flush with
the rear face of the block. The oil hole must be
aligned. A 3.2 mm (0.128 inch) diameter rod must be
able to pass through the hole.
(4) Measure the installed bushings at the front
and rear bores. The minimum inside diameter is
54.083 mm (2.1293 inch), and the maximum inside
diameter is is 54.147 mm. (2.1318 in.).
INSTALLATION - CAMSHAFT
(1) Lubricate the camshaft bushing and bores with
fresh engine oil or suitable equivalent.
(2) Liberally coat the camshaft lobes, journals, and
thrust washer with fresh engine oil or suitable equiv-
alent.
CAUTION: When installing the camshaft, DO NOT
push it in farther than it will go with the thrust
washer in place.(3) Install the camshaft and thrust plate. Align the
timing marks as shown (Fig. 64).
(4) Install the thrust plate bolts and tighten to 24
N´m (18 ft. lbs.) torque.
(5) Measure camshaft back lash and end clearance.
BACKLASH Ð 0.075Ð0.250 mm
(0.003Ð0.013 inch)
CLEARANCE Ð 0.025Ð0.500 mm
(0.001Ð0.020 inch)
(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 - INSTAL-
LATION). Install front crankshaft dust seal.
(13) Install the crankshaft damper with the speed
indicator ring (Refer to 9 - ENGINE/ENGINE
BLOCK/VIBRATION DAMPER - INSTALLATION).
Fig. 63 Oil Hole Alignment
1 - CAMSHAFT BUSHING
Fig. 64 Timing Mark Alignment
9 - 320 ENGINE 5.9L DIESELDR
CAMSHAFT & BEARINGS (IN BLOCK) (Continued)

CRANKSHAFT AND GEAR
DESCRIPTION
The crankshaft (Fig. 66) is a forged steel, integrally
balanced unit. It is supported by seven main bear-
ings, with position number six designated as the
thrust journal. The crankshaft is held in place by
main caps and 12 mm capscrews. The crankshaft
also has internal cross drillings to supply the con-
necting rods with engine oil.
REMOVALÐGEAR
(1) Remove the gear housing cover. (Refer to 9 -
ENGINE/VALVE TIMING/GEAR HOUSING COVER
- REMOVAL)
(2) Remove the crank gear using a heavy duty
puller.
(3) Split the gear and remove it from the crank-
shaft.
INSTALLATION - GEAR
(1) Remove all burrs and make sure the gear sur-
face on the end of the crankshaft is smooth.
(2) If removed, install a new alignment pin. Drive
the pin in using a ball- peen hammer, leaving it pro-truding 1.0 mm (0.039 inch) to 1.5 mm (0.059 inch)
above the crankshaft (Fig. 67).
WARNING: WEAR PROTECTIVE GLOVES TO PRE-
VENT INJURY.
CAUTION: DO NOT heat the gear longer than 45
minutes.
(3) Heat the crankshaft gear for 45 minutes at a
temperature of 149ÉC (300ÉF).Do not use torch,
gear failure will occur.
(4) Apply a thin coat of lubricant to the nose of the
crankshaft.
(5) Position the gear with the timing mark out and
install it on the crankshaft using the alignment pin.
Make sure the gear contacts the shoulder.
CRANKSHAFT MAIN
BEARINGS
STANDARD PROCEDURE - MAIN BEARING
CLEARANCE
Inspect the main bearing bores for damage or
abnormal wear.
(1) Remove bearings and measure main bearing
bore diameter after torquing main bearing cap bolts
to 176 Nm (130 ft. lbs.).
(2) Install the crankshaft main bearings and mea-
sure main bearing bore diameter with the main bolts
tightened to 176 N´m (130 ft. lbs.) torque (Fig. 68).
Fig. 66 Crankshaft
Fig. 67 Installing Alignment Pin
1 - ALIGNMENT PIN
9 - 322 ENGINE 5.9L DIESELDR

REAR MOUNT
REMOVAL
(1) Raise the vehicle on a hoist.
(2) Position a transmission jack in place.
(3) Remove support cushion stud nuts (Fig. 110).
(4) Raise rear of transmission and engine
SLIGHTLY.
(5) Remove the bolts holding the support cushion
to the transmission support bracket. Remove the sup-
port cushion.
(6) If necessary, remove the bolts holding the
transmission support bracket to the transmission.
INSTALLATION
(1) If removed, position the transmission support
bracket to the transmission. Install new attaching
bolts and tighten to 102 N´m (75 ft. lbs.) torque.
(2) Position support cushion to transmission sup-
port bracket. Install stud nuts and tighten to 47 N´m
(35 ft. lbs.) torque.
(3) Using the transmission jack, lower the trans-
mission and support cushion onto the crossmember
(Fig. 110).
(4) Install the support cushion bolts and tighten to
47 N´m (35 ft. lbs.) torque.
(5) Remove the transmission jack.
(6) Lower the vehicle.
LUBRICATION
DESCRIPTION
NOTE: Refer to (Fig. 111) and (Fig. 112) 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
Fig. 110 Engine Rear Support Cushion Assembly
DRENGINE 5.9L DIESEL 9 - 337

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 therocker 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. 111) and
(Fig. 112).
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.
9 - 338 ENGINE 5.9L DIESELDR
LUBRICATION (Continued)