heater DODGE RAM 2003 Service Repair Manual

Filter Removal
(1) The housing cover is equipped with spring clips
(Fig. 6) and is hinged with plastic tabs. Unlatch clips
from top of air cleaner housing and tilt housing cover
up for cover removal.
(2) Remove air cleaner element from air cleaner
housing.
INSTALLATION
(1) Before installing new air cleaner element (fil-
ter), clean inside of air cleaner housing.
(2) Position air cleaner cover to tabs on front of air
cleaner housing. Latch spring clips to seal cover to
housing.
CYLINDER HEAD
DESCRIPTION
The cylinder head is constructed of cast iron and is
a one piece cross flow design with four valves per cyl-
inder. The arrangement of two intake and two
exhaust valves per cylinder allows for a centrally
located injector. The cylinder head also includes an
integral intake manifold, an integral thermostat
housing, and a longitudal fuel return rifle, which
exits at the rear of the head. The 24 valve design
also includes integrally cast valve guides and hard-
ened intake and exhaust valve seat inserts.
REMOVAL
(1) Disconnect battery negative cables.
(2) Raise vehicle on hoist.
(3) Drain engine coolant.
(4) Disconnect exhaust pipe from turbocharger
elbow.
(5) Lower vehicle.
(6) Disconnect air inlet temperature/pressure sen-
sor.
(7) Remove air cleaner housing and snorkel from
the vehicle. Cap off turbocharger air inlet to prevent
intrusion of dirt or foreign material.
(8) Disconnect cab heater core supply and return
hoses from the cylinder head and heater pipe.
(9) Disconnect turbocharger oil drain tube at rub-
ber hose connection. Cap off open ports to prevent
intrusion of dirt or foreign material.
(10) Disconnect turbocharger oil supply line at the
turbocharger end. Cap off open ports to prevent
intrusion of dirt or foreign material.
(11) Remove exhaust manifold-to-cylinder head
bolts, spacers, heat shield, retention straps, and cab
heater plumbing. Remove exhaust manifold and tur-
bocharger from the vehicle as an assembly.
(12) Remove cooling fan assembly.
(13) Remove accessory drive belt (Refer to 7 -
COOLING/ACCESSORY DRIVE/DRIVE BELTS -
REMOVAL).
(14) Remove cooling fan support from cylinder
block.
(15) Remove upper generator bolt, loosen lower
generator bolt, and rotate generator away from cylin-
der head.
(16) Disconnect radiator upper hose from the ther-
mostat housing.
(17) Disconnect the Intake Air Temperature, Man-
ifold Air Pressure, and Coolant Temperature sensor
connector.
(18) Remove the engine harness to cylinder head
attaching bolts and P-clips at front of head.
(19) Remove the throttle linkage cover (Fig. 8).
(20) Remove the six (6) accelerator pedal position
sensor assembly-to-cylinder head bracket bolts (Fig.
9) and secure the entire assembly out of the way.
Disconnect the APPS connector (Fig. 10).It is not
necessary to disconnect the cables from the
throttle control assembly.
(21) Remove the intake air grid heater wires from
the grid heater.
(22) Remove engine oil level indicator tube attach-
ing bolt at fuel filter housing bracket and inlet air
connection..
(23) Remove the charge air cooler-to-air inlet hous-
ing pipe.
Fig. 7 FILTER MINDERŸ - 5.9L DIESEL
1 - PRESS BUTTON TO RESET
2 - YELLOW DISC
3 - RED ZONE
4 - TO AIR FILTER HOUSING
5 - FILTER MINDER
9 - 298 ENGINE 5.9L DIESELDR
AIR CLEANER ELEMENT (Continued)

(24) Remove the engine wire harness attaching
bolt and wire harness push-in fastener from air inlet
housing.
(25) Remove the air inlet housing and intake grid
heater from the intake manifold cover.
(26) Remove the two grid heater harness-to-cylin-
der head attaching bolts at front of cylinder head.(27) Remove the engine lift bracket from the rear
of the cylinder head.
(28)Remove the high pressure pump to fuel
rail fuel line as follows:
(a) Loosen fuel line nuts at fuel pump and at
fuel rail.
(b) Use a back-up wrench on the fitting at the
fuel pump to keep it from loosening.
(29) Remove the fuel rail to cylinder head fuel
lines as follows:
(a) Loosen No. 6 high pressure fuel line shield
and position out of way.
(b) Loosen the fuel line nuts at the fuel rail and
at the cylinder head.
(c) Remove the fuel line bracket bolts at the
intake manifold cover.
(30) Remove the fuel rail as follows:
(a) Remove fuel rail pressure sensor connector.
(b) Remove banjo fitting at pressure limiting
valve.
(c) Remove fuel rail bolts and fuel rail.
(31) Remove the low pressure lines as follows:
(a) Remove the fuel drain banjo fitting on the
front side of fuel filter housing.
(b) Remove the fuel drain banjo fitting on rear
side of fuel filter housing.
(c) Remove the fuel drain line support bracket
on rear side of filter housing.
(d) Remove fuel drain hose.
Fig. 8 Throttle Linkage Cover
1 - CABLE/LEVER/LINKAGE COVER
2 - PUSH UP LOWER TAB
3 - SCREWS/CLIPS (2)
4 - TAB PUSH HERE
Fig. 9 APPS Assembly
1 - LEVER
2 - MOUNTING BOLTS (6)
3 - WIRE HARNESS CLIP
4 - CALIBRATION SCREWS (NO ADJUSTMENT)
5 - APPS ASSEMBLY
Fig. 10 APPS Connector
1 - APPS
2-TAB
3 - PUSH FOR REMOVAL
4 - APPS CONNECTOR
DRENGINE 5.9L DIESEL 9 - 299
CYLINDER HEAD (Continued)

(e) Remove banjo fitting at bottom of fuel filter
housing.
(f) Disconnect fuel supply hose at lift pump.
(32) Disconnect fuel heater, water in fuel sensor,
and fuel lift pump connectors.
(33) Remove the fuel filter assembly-to-cylinder
head bolts and remove filter assembly from vehicle.
(34) Remove wire harness P-clip from cylinder
head (located behind filter housing).
(35) Remove the cylinder head cover(Refer to 9 -
ENGINE/CYLINDER HEAD/CYLINDER HEAD
COVER(S) - REMOVAL).
(36) Disconnect rocker housing injector harness
connectors.
(37) Remove injector harness nuts from injectors.
(38) Remove the rocker levers (Fig. 11), cross
heads and push rods (Fig. 12). Mark each component
so they can be installed in their original positions.
NOTE: The #5 cylinder exhaust and the #6 cylinder
intake and exhaust push rods are removed by lift-
ing them up and through the provided cowl panel
access holes. Remove the rubber plugs to expose
these relief holes.
(39) Remove the fuel return line and banjo bolt at
the rear of the cylinder head. Be careful not to drop
the two (2) sealing washers.
(40) Remove the fuel injectors (Refer to 14 - FUEL
SYSTEM/FUEL INJECTION/FUEL INJECTOR -
REMOVAL).(41) Remove rocker housing bolts and rocker hous-
ing and gasket.
(42) Reinstall the engine lift bracket at the rear of
cylinder head. Torque to 77 N´m (57 ft. lbs.).
(43) Remove twenty six (26) cylinder head-to-block
bolts.
(44) Attach an engine lift crane to engine lift
brackets and lift cylinder head off engine and out of
vehicle.
(45) Remove the head gasket and inspect for fail-
ure.
CLEANING
CLEANINGÐCYLINDER HEAD
CAUTION: Do not wire brush head surface while
fuel injectors are still installed. Fuel injector dam-
age can result.
Remove fuel injector before cleaning (if not already
removed during cylinder head removal).
Clean the carbon from the injector nozzle seat with
a nylon or brass brush.
Scrape the gasket residue from all gasket surfaces.
Wash the cylinder head in hot soapy water solution
(88ÉC or 140ÉF).
After rinsing, use compressed air to dry the cylin-
der head.
Polish the gasket surface with 400 grit paper. Use
an orbital sander or sanding block to maintain a flat
surface.
CLEANINGÐCROSSHEADS
Clean all crossheads in a suitable solvent. If neces-
sary, use a wire brush or wheel to remove stubborn
deposits. Rinse in hot water and blow dry with com-
pressed air.
Fig. 11 Rocker Arm and Pedestal Removal
1 - ROCKER ARM
2 - PEDESTAL
Fig. 12 Push Rod Removal
9 - 300 ENGINE 5.9L DIESELDR
CYLINDER HEAD (Continued)

(9) Install rocker housing and bolts. Tighten to 24
Nm (18 lb. ft.).
(10) Install fuel injector(Refer to 14 - FUEL SYS-
TEM/FUEL INJECTION/FUEL INJECTOR -
INSTALLATION).
(11) Install fuel injector tube and fuel injector tube
nut. Torqu to 50 N´m (37 ft. lbs.).
(12) Install injector harness nuts. Tighten to 1.5
Nm (13 lb. in.).
(13) Install cylinder head cover (Refer to 9 -
ENGINE/CYLINDER HEAD/CYLINDER HEAD
COVER(S) - INSTALLATION).
(14) Install wire harness P-clip to cylinder head
behind filter housing 24 N´m (18 ft. lbs.).
(15) Connect the IAT and MAP sensor connector.
(16) Install the fuel filter canister assembly and
torque mounting bolts to 24 N´m (18 ft. lbs.).
(17) Connect fuel lift pump, WIF sensor, and fuel
heater.
(18) Remove the engine lift bracket at rear of cyl-
inder head.
CAUTION: Failure to follow procedure will result in
fuel leaks and/or fuel system failure.
(19)Install the fuel rail and high pressure
fuel lines as follows:
(a) Hand tighten fuel rail bolts.
(b) Hand tighten fuel drain line to pressure lim-
iting valve. Hand tighten at fuel filter housing.
(c) Hand tighten fuel rail-to-cylinder head lines.(d) Install fuel line brace bolts-to-intake mani-
fold finger tight.
(e) Hand tighten fuel pump to fuel rail line.
(f) Torque fuel line nuts at cylinder head to 30
Nm ( 22 ft. lbs.).
(g) Torque fuel line nuts at fuel rail to 30 Nm
(22 ft. lbs.)
(h) Torque fuel pump to fuel rail line to 30 Nm
(22 ft. lbs.).
(i) Torque fuel drain banjo bolt at pressure lim-
iting valve and front of fuel filter housing to 24 Nm
(18 ft. lbs.).
(j) Torque fuel line brace bolts to 24 N´m (18 ft.
lbs.).
(k) Torque rail bolts to 24 Nm (18 ft. lbs.).
(l) Connect fuel pressure sensor.
(20) Install the engine lift bracket at the rear of
cylinder head. Torque to 77 N´m (57 ft. lbs.).
(21) Reposition number 6 fuel line shield and
torque to 43 N´m (32 ft. lbs.).
(22) Install the fuel filter to injection pump low
pressure line. Inspect and replace sealing washers if
necessary. Torque banjo bolts to 24 N´m (18 ft. lbs.).
(23) Connect fuel return line at back of cylinder
head hand tight.
(24) Connect fuel return line at filter housing hand
tight.
(25) Torque banjo connections at cylinder head and
fuel filter housing to 24 Nm (18 ft. lbs.)
(26) Install bracket to rear of filter housing.
Torque to 24 Nm (18 ft. lbs.).
(27) Using new gaskets, install the intake grid
heater and air inlet housing. Torque bolts to 24 N´m
(18 ft. lbs.).
(28) Install wire harness P-clip and push on clip to
air inlet housing.
(29) Connect engine oil level indicator tube at fuel
filter housing and at air inlet housing.
(30) Connect the APPS connector.
(31) Install the APPS assembly to the cylinder
head bracket and torque bolts to 24 N´m (18 ft. lbs.).
(32) Install the throttle linkage cover.
(33) Install the charge air cooler-to-air inlet hous-
ing duct assembly. Torque all clamps to 11 N´m (100
in. lbs.).
(34) Connect intake grid heater wires.
(35) Secure engine harness to front of cylinder
head with bolt at four locations.
(36) Connect engine coolant temperature sensor
connector.
(37) Connect radiator upper hose to thermostat
housing.
(38) Rotate generator into position. Install upper
bolt and torque upper and lower bolts.
(39) Install wire harness push-on clip below
bracket.
Fig. 20 Rocker Arm and Pedestal Removal
1 - ROCKER ARM
2 - PEDESTAL
DRENGINE 5.9L DIESEL 9 - 303
CYLINDER HEAD (Continued)

(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. 125).
(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.
INSTALLATION
(1) Using a new gasket, install the intake manifold
cover.
(2) Install the cover-to-cylinder head bolts that do
not hold down the fuel rail. Tighten the bolts to 24
N´m (18 ft. lbs.) torque.
(3) Install the high pressure rail and fuel lines
(Refer to 14 - FUEL SYSTEM/FUEL DELIVERY/
FUEL LINES - INSTALLATION).
(4) Using two (2) new gaskets, install the intake
air grid heater and air inlet housing. Position the
ground cable and install and tighten the bolts to 24
N´m (18 ft. lbs.) torque.
Fig. 124 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. 125 Intake Air Grid Heater
1 - INTAKE AIR GRID HEATER
2 - GASKET
9 - 346 ENGINE 5.9L DIESELDR
INTAKE MANIFOLD (Continued)

(5) Connect the manifold air temperature/pressure
sensor connector.
(6) Install and tighten the air intake heater power
supply nuts to 14 N´m (120 in. lbs.) torque.
(7) Install the APPS bracket. Torque fasteners to
43 N´m (32ft lbs.) torque.
(8) Install oil dipstick tube support at fuel filter
housing.
(9) Install the engine oil dipstick tube and mount-
ing bolt.
(10) Position the charge air cooler outlet tube onto
the air inlet housing. Tighten the clamps to 8 N´m
(72 in. lbs.) torque.
(11) Attach the engine wire harness to the air inlet
housing at two locations.
(12) Prime the fuel system. Refer to the fuel prim-
ing procedure in Group 14, Fuel System.
(13) Connect the battery negative cables.
EXHAUST MANIFOLD
REMOVAL
(1) Disconnect the battery negative cables.
(2) Raise vehicle on hoist.
(3) Disconnect the exhaust pipe from the turbo-
charger elbow.
(4) Lower vehicle.
(5) Disconnect the turbocharger air inlet hose.
(6) Remove air cleaner assembly.
(7) Disconnect the turbocharger oil supply line and
the oil drain tube from the turbocharger.
(8) Disconnect the charge air cooler inlet pipe from
the turbocharger.
(9) Remove the turbocharger and gasket from the
exhaust manifold.
(10) Remove the cab heater return pipe nuts from
the exhaust manifold stud. Position the tube out of
the way.
(11) Remove heat shield.
(12) Remove exhaust manifold bolt lockplates.
(13) Remove the exhaust manifold-to-cylinder head
bolts and spacers (Fig. 126).
(14) Remove the exhaust manifold and gaskets
(Fig. 126).
CLEANING
Clean the cylinder head and exhaust manifold seal-
ing surfaces with a suitable scraper. Use a Scotch-
BriteŸ pad or equivalent.
INSPECTION
Inspect the exhaust manifold for cracks. Measure
the exhaust manifold for flatness. Place a ruler over
all of the exhaust ports and insert a feeler gaugebetween the port flange and the ruler. Maximum
deviation from flat is 0.20 mm (.008 inch).
INSTALLATION
(1) Using new gaskets, install the exhaust mani-
fold and gaskets. Install the bolts and spacers and
tighten the bolts in the sequence shown in to 43 N´m
(32 ft. lbs.) torque.
(2) Retorque the four center bolts.
(3) Install heat shield and torque bolts to 24 Nm
(18 ft. lbs.).
(4) Install cab heater tube.
(5) Install exhaust manifold bolt retention straps.
(6) Install the cab heater return hose to the man-
ifold bolt stud. Tighten the nut to 24 N´m (18 ft. lbs.)
torque.
(7) Install the turbocharger and a new gasket.
Apply anti-seize to the studs and then tighten the
turbocharger mounting nuts to 43 N´m (32 ft. lbs.)
torque.
Fig. 126 Exhaust Manifold and Gaskets
1 - RETAINING STRAP
2 - BOLT (7)
3 - SPACER
4 - MANIFOLD, EXHAUST
5 - GASKET
6 - BOLT (5)
DRENGINE 5.9L DIESEL 9 - 347
INTAKE MANIFOLD (Continued)

(3) Discharge the air conditioning system, if
equipped (Refer to 24 - HEATING & AIR CONDI-
TIONING/PLUMBING - STANDARD PROCEDURE).
(4) Remove the upper crossmember.
(5) Remove the transmission oil cooler (Refer to 7 -
COOLING/TRANSMISSION/TRANS COOLER -
REMOVAL).
(6) Remove the serpentine belt (Refer to 7 - COOL-
ING/ACCESSORY DRIVE/DRIVE BELTS - REMOV-
AL).
(7) Remove the A/C compressor with the lines
attached (Refer to 24 - HEATING & AIR CONDI-
TIONING/PLUMBING/A/C COMPRESSOR -
REMOVAL). Set aside.
(8) If equipped, remove the condenser (Refer to 24
- HEATING & AIR CONDITIONING/PLUMBING/
A/C CONDENSER - REMOVAL).
(9) Remove the washer fluid reservoir bottle (Refer
to 8 - ELECTRICAL/WIPERS/WASHERS -
REMOVAL AND INSTALLATION).
(10) Disconnect the top radiator hose.
(11) Remove the fan (Refer to 7 - COOLING/EN-
GINE/RADIATOR FAN - REMOVAL).
(12) Remove the fan shroud.
(13) Disconnect the lower radiator hose.
(14) Disconnect the transmission cooler lines.
(15) Remove radiator (Refer to 7 - COOLING/EN-
GINE/RADIATOR - REMOVAL).
(16) Remove the generator with the wire connec-
tions (Refer to 8 - ELECTRICAL/CHARGING/GEN-
ERATOR - REMOVAL).
(17) Remove the air cleaner.
(18) Disconnect the throttle linkage.
(19) Remove throttle body (Refer to 14 - FUEL
SYSTEM/FUEL INJECTION/THROTTLE BODY -
REMOVAL).
(20) Remove the upper intake manifold (Refer to 9
- ENGINE/MANIFOLDS/INTAKE MANIFOLD -
REMOVAL).
(21) Remove the coil assemblies with the ignition
cables.
(22) Disconnect the heater hoses.
(23) Disconnect the power steering hoses, if
equipped.
(24) Perform the Fuel System Pressure release
procedure (Refer to 14 - FUEL SYSTEM/FUEL
DELIVERY - STANDARD PROCEDURE). Disconnect
the fuel line (Refer to 14 - FUEL SYSTEM/FUEL
DELIVERY/QUICK CONNECT FITTING - STAN-
DARD PROCEDURE).
(25) On Manual Transmission vehicles, remove the
shift lever.
(26) Raise and support the vehicle on a hoist.
(27) Remove the drain plug and drain the engine
oil.
(28) Loosen front engine mount thru-bolt nuts.(29) Remove the transmission cooler line brackets
from oil pan.
(30) Disconnect exhaust pipe at manifold.
(31) Disconnect the starter wires. Remove starter
motor (Refer to 8 - ELECTRICAL/STARTING/
STARTER MOTOR - REMOVAL).
(32) Remove transmission.
(33) Lower vehicle.
CAUTION: DO NOT lift the engine by the intake
manifold.
(34) Install an engine lifting fixture.
(35) Remove engine from vehicle and install
engine assembly on a repair stand.
INSTALLATION
(1) Remove engine from the repair stand and posi-
tion in the engine compartment. Position the thru-
bolt into the support cushion brackets.
(2) Install an engine support fixture.
(3) Raise and support the vehicle on a hoist.
(4) Install Transmission.
(5) Install the starter and connect the starter
wires (Refer to 8 - ELECTRICAL/STARTING/
STARTER MOTOR - INSTALLATION).
(6) Install exhaust pipe to manifold.
(7) Install the transmission cooler line brackets
from oil pan.
(8) Tighten the Front mount thru-bolts and nuts to
102N´m (75 ft. lbs.).
(9) Install the drain plug and tighten to 34 N´m
(25 ft. lbs.) torque.
(10) Prime oil pump by squirting oil in the oil fil-
ter mounting hole and filling the J-trap of the front
timing cover. When oil is running out, install oil filter
that has been filled with oil.
(11) Lower the vehicle.
(12) Remove engine lifting fixture.
(13) On Manual Transmission vehicles, install the
shift lever.
(14) Connect the fuel lines (Refer to 14 - FUEL
SYSTEM/FUEL DELIVERY/QUICK CONNECT FIT-
TING - STANDARD PROCEDURE).
(15) Connect the heater hoses.
(16) Install the upper intake manifold (Refer to 9 -
ENGINE/MANIFOLDS/INTAKE MANIFOLD -
INSTALLATION).
(17) Install the coil assemblies with the ignition
cables.
(18) Using a new gasket, install throttle body
(Refer to 14 - FUEL SYSTEM/FUEL INJECTION/
THROTTLE BODY - INSTALLATION).
(19) Connect the throttle linkage.
(20) Install the air cleaner box.
9 - 362 ENGINE 8.0LDR
ENGINE 8.0L (Continued)

fuel line (Refer to 14 - FUEL SYSTEM/FUEL DELIV-
ERY/QUICK CONNECT FITTING - STANDARD
PROCEDURE).
(9) Disconnect accelerator linkage and if so
equipped, the speed control and transmission kick-
down cables.
(10) Remove coil pack and bracket (Fig. 8).
(11) Disconnect the coil wires.
(12) Disconnect heat indicator sending unit wire.
(13) Disconnect heater hoses and bypass hose.
(14) Remove upper intake manifold and throttle
body as an assembly (Refer to 9 - ENGINE/MANI-
FOLDS/INTAKE MANIFOLD - REMOVAL).
(15) Remove cylinder head covers and gaskets
(Refer to 9 - ENGINE/CYLINDER HEAD/CYLIN-
DER HEAD COVER(S) - REMOVAL).
(16) Remove the EGR tube. Discard the gasket, for
right side only.
(17) Remove lower intake manifold (Refer to 9 -
ENGINE/MANIFOLDS/INTAKE MANIFOLD -
REMOVAL). Discard the flange side gaskets and the
front and rear cross-over gaskets.
(18) Disconnect exhaust pipe from exhaust mani-
fold.
(19) Remove exhaust manifolds and gaskets (Refer
to 9 - ENGINE/MANIFOLDS/EXHAUST MANIFOLD
- REMOVAL).
(20) Remove rocker arm assemblies and push rods
(Refer to 9 - ENGINE/CYLINDER HEAD/ROCKER
ARM / ADJUSTER ASSY - REMOVAL). Identify to
ensure installation in original locations.(21) Remove the head bolts from each cylinder
head and remove cylinder heads. Discard the cylin-
der head gasket.
(22) Remove spark plugs.
CLEANING
Clean all surfaces of cylinder block and cylinder
heads. Be sure material does not fall into the lifters
and surrounding valley.
Clean cylinder block front and rear gasket surfaces
using a suitable solvent.
Clean the exhaust manifold to cylinder head mat-
ing areas.
INSPECTION
Inspect all surfaces with a straightedge if there is
any reason to suspect leakage. The out-of-flatness
specifications are 0.0007 mm/mm (0.0004 inch/inch),
0.127 mm/152 mm (0.005 inch/6 inches) any direction
or 0.254 mm (0.010 inch) overall across head. If
exceeded, either replace head or lightly machine the
head surface.
The cylinder head surface finish should be
1.78-4.57 microns (15-80 microinches).
Inspect push rods. Replace worn or bent rods.
Inspect rocker arms. Replace if worn or scored.
INSTALLATION
(1) Position the new cylinder head gaskets onto
the cylinder block.
(2) Position the cylinder heads onto head gaskets
and cylinder block.
(3) Tighten the cylinder head bolts in two steps
(Fig. 9):
²Step 1ÐTighten all cylinder head bolts, in
sequence, to 58 N´m (43 ft. lbs.) torque.
²Step 2ÐTighten all cylinder head bolts, in
sequence, to 143 N´m (105 ft. lbs.) torque.
²
CAUTION: When tightening the rocker arm bolts,
make sure the piston in that cylinder is NOT at
TDC. Contact between the valves and piston could
occur.
Fig. 8 Coil Pack and Bracket
1 - COIL PACKS AND BRACKET
2 - MOUNTING BOLTS (4)
Fig. 9 Cylinder Head Bolt Tightening Sequence
9 - 372 ENGINE 8.0LDR
CYLINDER HEAD (Continued)

(4) Install push rods and rocker arm assemblies in
their original position (Refer to 9 - ENGINE/CYLIN-
DER HEAD/ROCKER ARM / ADJUSTER ASSY -
INSTALLATION).
(5) Install lower intake manifold (Refer to 9 -
ENGINE/MANIFOLDS/INTAKE MANIFOLD -
INSTALLATION).
(6) Install the upper intake manifold onto the
lower intake manifold (Refer to 9 - ENGINE/MANI-
FOLDS/INTAKE MANIFOLD - INSTALLATION).
(7) Install the exhaust manifolds and new gaskets
(Refer to 9 - ENGINE/MANIFOLDS/EXHAUST
MANIFOLD - INSTALLATION).
(8) Install exhaust pipe to the exhaust manifold.
Tighten the bolts to 34 n´m (25 ft. lbs.) torque.
(9) Using a new gasket, position the EGR tube to
the intake manifold and the exhaust manifold.
Tighten the EGR tube nut to 34 N´m (25 ft. lbs.)
torque. Tighten the bolts to 20 N´m (174 in. lbs.)
torque.
(10) Install the heat shields and the washers.
Make sure that heat shields tabs hook over the
exhaust gasket.Tighten the nuts to 15 N´m (132 in.
lbs.) torque.
(11) Adjust and Install the spark plugs (Refer to 8
- ELECTRICAL/IGNITION CONTROL/SPARK
PLUG - INSTALLATION).
(12) Install coil packs and bracket. Tighten the
bracket bolts to 21 N´m (190 in. lbs.) torque. Connect
the coil wires.
(13) Connect heat indicator sending unit wire.
(14) Connect the heater hoses and bypass hose.
(15) Connect the accelerator linkage and if so
equipped, the speed control and transmission kick-
down cables.
(16) Install the fuel line (Refer to 14 - FUEL SYS-
TEM/FUEL DELIVERY/QUICK CONNECT FIT-
TING - STANDARD PROCEDURE).
(17) Install the generator (Refer to 8 - ELECTRI-
CAL/CHARGING/GENERATOR - INSTALLATION)
and drive belt (Refer to 7 - COOLING/ACCESSORY
DRIVE/DRIVE BELTS - INSTALLATION).
(18) Install the intake manifold-to-generator
bracket support rod. Tighten the bolts to 41 N´m (30
ft. lbs.) torque.
(19) The cylinder head cover gasket can be used
again. Install the gasket onto the head rail.For the
left side the number tab is at the front of
engine with the number up. For the right side
the number tab is at the rear of engine with the
number up.
CAUTION: The cylinder head cover fasteners have a
special plating. DO NOT use alternative fasteners.(20) Install cylinder head cover (Refer to 9 -
ENGINE/CYLINDER HEAD/CYLINDER HEAD
COVER(S) - INSTALLATION).
(21) Install closed crankcase ventilation system.
(22) Connect the evaporation control system.
(23) Install the air cleaner.
(24) Fill cooling system (Refer to 7 - COOLING -
STANDARD PROCEDURE).
(25) Connect the negative cable to the battery.
(26) Check for leaks (fuel, oil, antifreeze, etc.).
CYLINDER HEAD COVER(S)
DESCRIPTION
Die-cast magnesium cylinder head covers (Fig. 10)
reduce noise and provide a good sealing surface. A
steel backed silicon gasket is used with the cylinder
head cover. This gasket can be used again.
REMOVAL
Die-cast magnesium cylinder head covers (Fig. 12)
reduce noise and provide a good sealing surface. A
steel backed silicon gasket is used with the cylinder
head cover (Fig. 11).
(1) Disconnect the negative cable from the battery.
(2) Disconnect closed ventilation system and evap-
oration control system from cylinder head cover.
Identify each system for installation.
(3) Remove the upper intake manifold to remove
the right side head cover (Refer to 9 - ENGINE/
MANIFOLDS/INTAKE MANIFOLD - REMOVAL).
Fig. 10 Cylinder Head Cover
1 - CYLINDER HEAD COVER
DRENGINE 8.0L 9 - 373
CYLINDER HEAD (Continued)

(7) Using a new pressure relief valve gasket,
install the relief valve plug. Tighten the plug to 20
N´m (15 ft. lbs.) torque.
(8) Install oil filter that has been filled with oil.
INTAKE MANIFOLD
DESCRIPTION
The aluminum intake manifold (Fig. 65) has two
plenum chambers an upper and lower which supply
air to five runners each. Passages across the longitu-
dinal center of the manifold feed air from the throttle
body to the plenum chambers.
DIAGNOSIS AND TESTINGÐINTAKE
MANIFOLD LEAKAGE
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.
(1) Start the engine.
(2) Spray a small stream of water at the suspected
leak area.(3) If a change in RPMs occur, the area of the sus-
pected leak has been found.
(4) Repair as required.
REMOVAL
(1) Disconnect the negative cable from the battery.
(2) Drain the cooling system (Refer to 7 - COOL-
ING - STANDARD PROCEDURE).
(3) Remove the accessory drive belt (Refer to 7 -
COOLING/ACCESSORY DRIVE/DRIVE BELTS -
REMOVAL).
(4) Remove the generator brace and generator
(Fig. 66).
(5) Remove the A/C compressor brace (Fig. 66).
Remove the compressor and set aside.
(6) Remove the air cleaner cover and filter.
Remove the air cleaner housing (Fig. 67). Discard the
gasket.
(7) Perform the Fuel System Pressure release pro-
cedure (Refer to 14 - FUEL SYSTEM/FUEL DELIV-
ERY - STANDARD PROCEDURE). Disconnect the
fuel lines (Refer to 14 - FUEL SYSTEM/FUEL
DELIVERY/QUICK CONNECT FITTING - STAN-
DARD PROCEDURE).
(8) Disconnect the accelerator linkage and if so
equipped, the speed control and transmission kick-
down cables.
(9) Remove the coil assemblies with the ignition
wires.
(10) Disconnect the vacuum lines.
(11) Disconnect the heater hoses and bypass hose.
(12) Remove the closed crankcase ventilation and
evaporation control systems.
Fig. 65 Upper and Lower Intake ManifoldÐ8.0L
Engine
1 - UPPER INTAKE MANIFOLD
2 - THROTTLE BODY (MPI)
3 - LOWER INTAKE MANIFOLD
Fig. 66 Generator and A/C Compressor Braces
1 - GENERATOR
2 - INTAKE MANIFOLD TO GENERATOR BRACE
3 - A/C COMPRESSOR
4 - INTAKE MANIFOLD TO A/C COMPRESSOR BRACE
DRENGINE 8.0L 9 - 401
OIL PUMP (Continued)