2003 DODGE RAM Heater core

(3) Recover refrigerant from a/c system, if
equipped (Refer to 24 - HEATING & AIR CONDI-
TIONING/PLUMBING - STANDARD PROCEDURE).
(4) Remove the a/c condenser, if equipped (Refer to
24 - HEATING & AIR CONDITIONING/PLUMBING/
A/C CONDENSER - REMOVAL).
(5) Remove the transmission oil cooler (Refer to 7 -
COOLING/TRANSMISSION/TRANS COOLER -
REMOVAL).
(6) Remove the washer bottle from the fan shroud.
(7) Remove the viscous fan/drive (Refer to 7 -
COOLING/ENGINE/RADIATOR FAN - REMOVAL).
(8) Remove radiator (Refer to 7 - COOLING/EN-
GINE/RADIATOR - REMOVAL).
(9) Remove the upper crossmember and top core
support.
(10) Remove the accessory drive belt (Refer to 7 -
COOLING/ACCESSORY DRIVE/DRIVE BELTS -
REMOVAL).
(11) Remove the A/C compressor with the lines
attached. Secure compressor out of the way.
(12) Remove generator assembly (Refer to 8 -
ELECTRICAL/CHARGING/GENERATOR - REMOV-
AL).
(13) Remove the air cleaner resonator and duct
work as an assembly.
(14) Disconnect the throttle linkage (Refer to 14 -
FUEL SYSTEM/FUEL INJECTION/THROTTLE
CONTROL CABLE - REMOVAL).
(15) Remove throttle body (Refer to 14 - FUEL
SYSTEM/FUEL INJECTION/THROTTLE BODY -
REMOVAL).
(16) Remove the intake manifold (Refer to 9 -
ENGINE/MANIFOLDS/INTAKE MANIFOLD -
REMOVAL).
(17) Remove the distributor cap and wiring.
(18) Disconnect the heater hoses.
(19) Disconnect the power steering hoses, if
equipped.
(20) Perform the Fuel System Pressure Release
procedure (Refer to 14 - FUEL SYSTEM/FUEL
DELIVERY - STANDARD PROCEDURE).
(21) Disconnect the fuel supply line (Refer to 14 -
FUEL SYSTEM/FUEL DELIVERY/QUICK CON-
NECT FITTING - STANDARD PROCEDURE).
(22) On Manual Transmission vehicles, remove the
shift lever (Refer to 21 - TRANSMISSION/TRANS-
AXLE/MANUAL/SHIFT COVER - REMOVAL).
(23) Raise and support the vehicle on a hoist and
drain the engine oil.
(24) Remove engine front mount thru-bolt nuts.
(25) Disconnect the transmission oil cooler lines
from their retainers at the oil pan bolts.
(26) Disconnect exhaust pipe at manifolds.(27) Disconnect the starter wires. Remove starter
motor (Refer to 8 - ELECTRICAL/STARTING/
STARTER MOTOR - REMOVAL).
(28) Remove the dust shield and transmission
inspection cover.
(29) Remove drive plate to converter bolts (Auto-
matic transmission equipped vehicles).
(30) Remove transmission bell housing to engine
block bolts.
(31) Lower the vehicle.
(32) Install an engine lifting fixture.
(33) Separate engine from transmission, 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 engine lifting device.
(3) Lower engine into compartment and align
engine with transmission:
²Manual Transmission: Align clutch disc assem-
bly (if disturbed). Install transmission input shaft
into clutch disc while mating engine and transmis-
sion surfaces. Install two transmission to engine
block mounting bolts finger tight.
²Automatic Transmission: Mate engine and trans-
mission and install two transmission to engine block
mounting bolts finger tight.
(4) Lower engine assembly until engine mount
through bolts rest in mount perches.
(5) Install remaining transmission to engine block
mounting bolts and tighten.
(6) Tighten engine mount through bolts.
(7) Install drive plate to torque converter bolts.
(Automatic transmission models)
(8) Install the dust shield and transmission cover.
(9) Install the starter and connect the starter
wires (Refer to 8 - ELECTRICAL/STARTING/
STARTER MOTOR - INSTALLATION).
(10) Install exhaust pipe to manifold.
(11) Install the transmission cooler line brackets to
the oil pan.
(12) Install the drain plug and tighten to 34 N´m
(25 ft. lbs.) torque.
(13) Lower the vehicle.
(14) Remove engine lifting fixture.
(15) On Manual Transmission vehicles, install the
shift lever (Refer to 21 - TRANSMISSION/TRANS-
AXLE/MANUAL/SHIFT COVER - INSTALLATION).
(16) Connect the fuel supply line (Refer to 14 -
FUEL SYSTEM/FUEL DELIVERY/QUICK CON-
NECT FITTING - STANDARD PROCEDURE).
(17) Connect the power steering hoses, if equipped.
(18) Connect the heater hoses.
9 - 234 ENGINE - 5.9LDR
ENGINE - 5.9L (Continued)

²Installing an insert into the tapped hole to bring
the hole back to its original thread size.
STANDARD PROCEDUREÐHYDROSTATIC
LOCK
CAUTION: DO NOT use the starter motor to rotate
the crankshaft. Severe damage could occur.
When an engine is suspected of hydrostatic lock
(regardless of what caused the problem), follow the
steps below.
(1) Disconnect the negative cable(s) from the bat-
tery.
(2) Inspect air cleaner, induction system, and
intake manifold to ensure system is dry and clear of
foreign material.
(3) Place a shop towel around the fuel injectors to
catch any fluid that may possibly be under pressure
in the cylinder head. Remove the fuel injectors (Refer
to 14 - FUEL SYSTEM/FUEL INJECTION/FUEL
INJECTOR - REMOVAL).
(4) With all injectors removed, rotate the crank-
shaft using the crankshaft barring tool (PN 7471±B).
(5) Identify the fluid in the cylinders (coolant, fuel,
oil, etc.).
(6) Be sure all fluid has been removed from the
cylinders.
(7) Repair engine or components as necessary to
prevent this problem from occurring again.
(8) Squirt a small amount of engine oil into the
cylinders to lubricate the walls. This will prevent
damage on restart.
(9) Install fuel injectors (Refer to 14 - FUEL SYS-
TEM/FUEL INJECTION/FUEL INJECTOR -
INSTALLATION).
(10) Drain engine oil. Remove and discard the oil
filter (Refer to 9 - ENGINE/LUBRICATION/OIL FIL-
TER - REMOVAL).
(11) Install the drain plug. Tighten the plug to 50
N´m (37 ft. lbs.) torque.
(12) Install a new oil filter (Refer to 9 - ENGINE/
LUBRICATION/OIL FILTER - INSTALLATION).
(13) Fill engine crankcase with the specified
amount and grade of oil (Refer to LUBRICATION &
MAINTENANCE/FLUID TYPES - SPECIFICA-
TIONS).
(14) Connect the negative cable(s) to the battery.
(15) Start the engine and check for any leaks.
REMOVAL
REMOVALÐENGINE
(1) Disconnect both battery negative cables.
(2) Disconnect engine grid heater harness at grid
heater relays.(3) Disconnect electrical connections from rear of
alternator.
(4) Recover A/C refrigerant. (Refer to 24 - HEAT-
ING & AIR CONDITIONING/PLUMBING - STAN-
DARD PROCEDURE).
(5) Raise vehicle on a hoist.
(6) Drain engine coolant (Refer to 7 - COOLING -
STANDARD PROCEDURE).
(7) Remove engine oil drain plug and drain engine
oil.
(8) Remove fan/drive assembly. Refer to Section 7
± Fan/Drive Removal
(9) Remove radiator upper hose.
(10) Remove upper fan shroud mounting bolts.
(11) Disconnect the coolant recovery bottle hose
from the radiator fill neck and remove bottle.
(12) Using a 36mm wrench, remove viscous fan/
drive assembly. (Refer to 7 - COOLING/ENGINE/RA-
DIATOR FAN - REMOVAL).
(13) Remove cooling fan and shroud together.
(14) Disconnect heater core supply and return
hoses from the cylinder head fitting and coolant pipe.
(15) Raise vehicle on a hoist.
(16) Remove transmission and transfer case (if
equipped).
(17) Disconnect exhaust pipe from turbocharger
extension pipe.
(18) Disconnect engine harness to vehicle harness
connectors.
(19) Remove starter motor (Refer to 8 - ELECTRI-
CAL/STARTING/STARTER MOTOR - REMOVAL).
(20) Remove flywheel/flexplate.
(21) Remove transmission adapter
(22) Disconnect A/C suction/discharge hose from
the rear of the A/C compressor.
(23) Lower vehicle.
(24) Disconnect lower radiator hose from radiator
outlet.
(25) Automatic transmission models:
(26) Disconnect transmission oil cooler lines from
in front of radiator using special tool #6931
(27) Remove radiator. (Refer to 7 - COOLING/EN-
GINE/RADIATOR - REMOVAL).
(28) If A/C equipped, disconnect A/C condenser
refrigerant lines.
(29) Disconnect charge air cooler piping.
(30) Remove charge air cooler mounting bolts.
(31) Remove charge air cooler (and A/C condenser
if equipped) from vehicle.
(32) Remove damper and speed indicator ring from
front of engine.
(33) Disconnect engine block heater connector.
(34) Disconnect A/C compressor and pressure sen-
sor electrical connectors.
9 - 290 ENGINE 5.9L DIESELDR
ENGINE 5.9L DIESEL (Continued)

(2) Lower engine into the engine compartment and
install the engine the engine mount through bolts
and nuts.
(3) Tighten the mount through bolts and nuts to
88 N-m (65 ft-lbs) torque.
(4) Remove the engine lifting device (Tool 9009).
(5) Check cylinder head capscrew length and
install into cylinder head.
(6) Torque alternately to 70 N-m (52 ft-lbs). Torque
alternately to 105 N-m (77 ft-lbs). Rotate 90 degrees.
(7) Install rocker housing. Torque to 24 N-m (18 ft-
lbs). Refer to Section 9 Rocker Housing Installation
(8) Replace injector o-ring and sealing washer on
injectors #5 and #6. Install injectors and alternately
tighten hold-down capscrews to 10 N-m (89 in-lbs).
(9) Install fuel connector tube and fuel connector
tube nut. Torque to 50 N-m (37 ft-lb). 10.
(10) Install #5 and #6 high pressure fuel lines. Fol-
low correct torque sequence per section 14. Torque
fuel line fittings to 30 N-m (22 ft-lb). Torque brace
capscrew to 24 N-m (18 ft-lb).
(11) Install rear engine lift bracket. Torque to 77
N-m (57 ft-lb).
(12) Install push tubes, rocker arms, and pedestals
for cylinders #4, #5, and #6. Torque the mounting
bolts to 36 N-m (27 ft-lbs).
(13) Reset valve lash on cylinders #4, #5, and #6.
Torque adjusting nuts to 24 N-m (18 ft-lbs).
(14) Install cylinder head cover. Torque to 24 N-m
(18 ft-lbs).(Refer to 9 - ENGINE/CYLINDER HEAD -
INSTALLATION).
(15) Connect breather tube and lube oil drain tube
to breather housing. Install breather housing. Torque
capscrews to 24 N-m (18 ft-lbs)
(16) Connect fuel supply and return hoses.
(17) Connect ECM ground to hydroform screw.
Connect ECM power connector.
(18) Install the APPS cable(s) to the APPS. Install
the throttle linkage cover.
(19) Install the power steering pump.
(20) Install the damper and speed indicator ring.
Torque to 40 N-m (30 ft-lb) plus 60 degrees.
(21) Connect the engine block heater connection.
(22) Connect the A/C compressor and pressure sen-
sor connectors
(23) Install the charge air cooler and a/c condenser
(if equipped). Install and tighten the charge air
cooler mounting bolts to 2 N-m (17 in-lbs).
(24) Connect the charge air cooler piping. Torque
all clamps to 8 N-m (72 in-lbs).
(25) Connect the a/c refrigerant lines to the a/c
condenser (if equipped).
(26) Install the radiator upper support panel.
(27) Install radiator.
(28) Connect the transmission quick-connect oil
cooler lines.(29) Raise vehicle.
(30) Connect a/c compressor suction/discharge hose
(if equipped).
(31) Install the radiator lower hose and clamps.
(32) Install the battery negative cables to the
engine block on the driver and passenger side.
(33) Install the transmission adapter with a new
camshaft rectangular ring seal. Torque to 77 N-m (57
ft-lb).
(34) Install the flywheel/flexplate. Torque to 137
N-m (101 ft-lb).
(35) Install the starter motor. Torque to 43 N-m
(32 ft-lb). (Refer to 8 - ELECTRICAL/STARTING/
STARTER MOTOR - INSTALLATION).
(36) Connect engine to vehicle harness connectors.
(37) Install transmission and transfer case (if
equipped).
(38) Connect the exhaust pipe to the turbocharger
elbow.
(39) Connect the transmission auxiliary oil cooler
lines (if equipped).
(40) Lower the vehicle.
(41)
Connect the heater core supply and return hoses.
(42) Install the cooling fan and upper fan shroud
at the same time. (Refer to 7 - COOLING/ENGINE/
RADIATOR FAN - INSTALLATION).
(43) Install the coolant recovery bottle.
(44) Install the windshield washer bottle.
(45) Install the upper radiator hose and clamps.
(46) Raise vehicle.
(47) Connect electronically controlled fan drive
wire harness. Install lower radiator fan shroud.
(48) Change oil filter and install new engine oil.
(49) Fill the cooling system with coolant. (Refer to
7 - COOLING - STANDARD PROCEDURE).
(50) Connect grid heater harness at grid heater
relays.
(51) Connect electrical connections to rear of alter-
nator.
(52) Start the engine and inspect for engine oil,
coolant, and fuel leaks.
INSTALLATIONÐCRANKCASE BREATHER
(1) Install a new o-ring onto the breather element.
(2) Lubricate o-ring and install into cylinder head
cover. Torque capscrews to 10 N´m (89 in. lbs.).
(3) Connect breather tube and lube oil drain tube.
(4) Install breather cover (Fig. 4). Torque to 24
N´m (18 ft. lbs.)
(5) Install oil fill cap.
9 - 292 ENGINE 5.9L DIESELDR
ENGINE 5.9L DIESEL (Continued)

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)

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)

SPECIFICATIONS - TORQUE
DESCRIPTION N´m Ft. In.
Lbs. Lbs.
Adjusting StrapÐBolt 23 Ð 200
Air Heater Power SupplyÐ
Nuts14 Ð 124
Air Inlet HousingÐBolts 24 18 Ð
Cab Heater Supply/Return
LineÐNuts24 18 Ð
Exhaust ClampÐNuts 48 35 Ð
Exhaust Manifold to Cylinder
HeadÐBolts
(Diesel Engine) 43 32 Ð
Exhaust Manifold to Cylinder
HeadÐBolts
(5.9L) 31 23 Ð
Exhaust Manifold to Cylinder
HeadÐBolts
(8.0L) 22 Ð 195
Exhaust Pipe to ManifoldÐ
Bolts31 23 Ð
Generator MountingÐBolts 41 30 Ð
Charge Air Cooler
MountingÐBolts2Ð17
Charge Air Cooler DuctÐ
Nuts11 Ð 9 5
Heat ShieldÐNuts and Bolts 11 Ð 95
Turbocharger flange studs 24 18 Ð
Turbocharger MountingÐ
Nuts43 32 Ð
Turbocharger Oil Drain
TubeÐBolts24 18 Ð
Turbocharger Oil Supply
LineÐFitting24 18 Ð
Turbocharger V-Band
ClampÐNut9Ð75
Turbocharger Oil Supply
fitting (at Turbocharger)36 27 Ð
Turbocharger Oil Supply
fitting (at lube filter head)24 18 Ð
Turbocharger Drain Hose
Clamps8Ð71
SPECIAL TOOLS
CATALYTIC CONVERTER
DESCRIPTION - CATALYTIC CONVERTER
WARNING: THE NORMAL OPERATING TEMPERA-
TURE OF THE EXHAUST SYSTEM IS VERY HIGH.
THEREFORE, NEVER WORK AROUND OR ATTEMPT
TO SERVICE ANY PART OF THE EXHAUST SYSTEM
UNTIL IT IS COOLED. SPECIAL CARE SHOULD BE
TAKEN WHEN WORKING NEAR THE CATALYTIC
CONVERTER. THE TEMPERATURE OF THE CON-
VERTER RISES TO A HIGH LEVEL AFTER A SHORT
PERIOD OF ENGINE OPERATION TIME.
CAUTION: DO NOT remove spark plug wires from
plugs or by any other means short out cylinders.
Failure of the catalytic converter can occur due to a
temperature increase caused by unburned fuel
passing through the converter.
The stainless steel catalytic converter body is
designed to last the life of the vehicle. Excessive heat
can result in bulging or other distortion, but exces-
sive heat will not be the fault of the converter. If
unburned fuel enters the converter, overheating may
occur. If a converter is heat-damaged, correct the
cause of the damage at the same time the converter
is replaced. Also, inspect all other components of the
exhaust system for heat damage.
Unleaded gasoline must be used to avoid con-
taminating the catalyst core.
50 State emission vehicles incorporate two mini
catalytic converters located after the exhaust mani-
folds and before the inline catalytic converter.
OPERATION
The catalytic converter captures and burns any
unburned fuel mixture exiting the combustion cham-
bers during the exhaust stroke of the engine. This
process aids in reducing emissions output.
TURBOCHARGER TESTER 9022
11 - 4 EXHAUST SYSTEMDR
EXHAUST SYSTEM (Continued)

HEATING & AIR CONDITIONING
TABLE OF CONTENTS
page page
HEATING & AIR CONDITIONING
DESCRIPTION
DESCRIPTION - HEATER AND AIR
CONDITIONER........................1
DESCRIPTION - COOLING SYSTEM
REQUIREMENTS.......................1
DESCRIPTION - REFRIGERANT SYSTEM
SERVICE PORT........................1
OPERATION
OPERATION - HEATER AND AIR
CONDITIONER........................1
OPERATION - REFRIGERANT SYSTEM
SERVICE PORT........................2DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTING - A/C
PERFORMANCE.......................2
DIAGNOSIS AND TESTING - HEATER
PERFORMANCE.......................5
STANDARD PROCEDURE - DIODE
REPLACEMENT.......................7
SPECIFICATIONS
A/C APPLICATION TABLE................7
SPECIFICATIONS......................8
CONTROLS.............................9
DISTRIBUTION..........................24
PLUMBING.............................31
HEATING & AIR
CONDITIONING
DESCRIPTION
DESCRIPTION - HEATER AND AIR
CONDITIONER
All vehicles are equipped with a common HVAC
housing assembly (Fig. 1). The system combines air
conditioning, heating, and ventilating capabilities in
a single unit housing mounted under the instrument
panel.
DESCRIPTION - COOLING SYSTEM
REQUIREMENTS
To maintain the performance level of the HVAC
system, the engine cooling system must be properly
maintained. The use of a bug screen is not recom-
mended. Any obstructions in front of the radiator or
condenser will reduce the performance of the air con-
ditioning and engine cooling systems.
The engine cooling system includes the heater core
and the heater hoses. Refer to Engine Cooling for
more information before the opening of, or attempt-
ing any service to the engine cooling system.
DESCRIPTION - REFRIGERANT SYSTEM
SERVICE PORT
The two refrigerant system service ports are used
to charge, recover/recycle, evacuate, and test the air
conditioning refrigerant system. Unique service port
coupler sizes are used on the R-134a system, toensure that the refrigerant system is not accidentally
contaminated by the use of the wrong refrigerant
(R-12), or refrigerant system service equipment.
OPERATION
OPERATION - HEATER AND AIR CONDITIONER
The heater air conditioner are blend-air type sys-
tems. In a blend-air system, a blend door controls the
amount of unconditioned air (or cooled air from the
evaporator on models with air conditioning) that is
allowed to flow through, or around, the heater core. A
temperature control knob on the A/C Heater control
panel determines the discharge air temperature by
controlling an electric actuator, which moves the
blend door. This allows an almost immediate control
of the output air temperature of the system.
The mode control knob on the A/C Heater control
panel is used to direct the conditioned air to the
selected system outlets. Both mode control switches
use electric actuators to control the mode doors.
On all vehicles, the outside air intake can be shut
off by selecting the Recirculation Mode with the
mode control knob. This will operate a electric actu-
ated recirculation door that closes off the outside
fresh air intake and recirculates the air that is
already inside the vehicle.
The air conditioner for all models is designed for
the use of non-CFC, R-134a refrigerant. The air con-
ditioning system has an evaporator to cool and dehu-
midify the incoming air prior to blending it with the
heated air. This air conditioning system uses a fixed
orifice tube in the liquid line near the condenser out-
let tube to meter refrigerant flow to the evaporator
DRHEATING & AIR CONDITIONING 24 - 1

Pressure Diagnosis
Condition Possible Causes Correction
4. Air in the refrigerant
system.4. See Plumbing/Diagnosis and Testing -
Refrigerant System Leaks in this group. Test the
refrigerant system for leaks. Repair, evacuate and
charge the refrigerant system, if required.
5. Engine overheating. 5. Refer to Cooling for more information. Test the
cooling system and repair, if required.
The low side pressure is too
high, and the high side
pressure is too low.1. Accessory drive belt
slipping.1. Refer to Cooling for more information. Inspect
the accessory drive belt condition and tension.
Tighten or replace the accessory drive belt, if
required.
2. Fixed orifice tube not
installed.2. See A/C Orifice Tube in this group. Replace
the liquid line, if required.
3. Faulty compressor. 3. See A/C Compressor in this group. Replace
the compressor, if required.
The low side pressure is too
low, and the high side
pressure is too high.1. Restricted refrigerant flow
through the refrigerant lines.1. See Liquid, Suction, and Discharge Line in this
group. Inspect the refrigerant lines for kinks, tight
bends or improper routing. Correct the routing or
replace the refrigerant line, if required.
2. Restricted refrigerant flow
through the fixed orifice tube.2. See A/C Orifice Tube in this group. Replace
the liquid line, if required.
3. Restricted refrigerant flow
through the condenser.3. See A/C Condenser in this group. Replace the
restricted condenser, if required.
DIAGNOSIS AND TESTING - HEATER
PERFORMANCE
Before performing the following tests, refer to Cool-
ing for the procedures to check the engine coolant
level and flow, engine coolant reserve/recovery sys-
tem operation, accessory drive belt condition and ten-
sion, radiator air flow and the fan drive operation.
Also be certain that the accessory vacuum supply
line is connected at the engine vacuum source.
MAXIMUM HEATER OUTPUT
Engine coolant is delivered to the heater core
through two heater hoses. With the engine idling at
normal operating temperature, set the temperature
control knob in the full hot position, the mode control
switch knob in the floor position, and the blower
motor switch knob in the highest speed position.
Using a test thermometer, check the temperature of
the air being discharged at the HVAC housing floor
outlets. Compare the test thermometer reading to the
Temperature Reference chart.
Temperature Reference
Ambient Air Temperature15.5É C
(60É F)21.1É C
(70É F)26.6É C
(80É F)32.2É C
(90É F)
Minimum Air Temperature at
Floor Outlet62.2É C
(144É F)63.8É C
(147É F)65.5É C
(150É F)67.2É C
(153É F)
DRHEATING & AIR CONDITIONING 24 - 5
HEATING & AIR CONDITIONING (Continued)