engine system DODGE RAM 2003 Service User Guide

(2) Install the one mounting bolt for the adjustable
pedal motor (Fig. 46).
(3) Clip the cable fasteners to the support.
(4) Reconnect the electrical connector.
(5) Reconnect the adjustable pedal cables to the
brake and accelerator pedals.
(6) Install the new brake light switch (Refer to 8 -
ELECTRICAL/LAMPS/LIGHTING - EXTERIOR/
BRAKE LAMP SWITCH - REMOVAL).
(7) Install the kneeblocker (Refer to 23 - BODY/IN-
STRUMENT PANEL/STEERING COLUMN OPEN-
ING COVER - INSTALLATION).
(8) Reconnect the negative battery cable.
(9) Check for proper operation of the pedals.
POWER BRAKE BOOSTER
DESCRIPTION
All models use a tandem diaphragm, power brake
booster.
NOTE: The power brake booster is not a repairable
component. The booster must be replaced as an
assembly if diagnosis indicates a malfunction has
occurred.
OPERATION
The booster unit consists of a single housing
divided into two by a tandem diaphragm. The outer
edge of the diaphragm is secured to the housing. The
booster push rod, which connects the booster to the
brake pedal and master cylinder, is attached to the
center of the diaphragm. A check valve is used in the
booster outlet connected to the engine intake mani-
fold. Power assist is generated by utilizing a combi-
nation of vacuum and atmospheric pressure to boost
brake assist.
REMOVAL
(1) Remove master cylinder. (Refer to 5 - BRAKES/
HYDRAULIC/MECHANICAL/MASTER CYLINDER -
REMOVAL).
(2) Disconnect vacuum line at booster.
(3) Remove clip securing booster push rod to brake
pedal (Refer to 5 - BRAKES/HYDRAULIC/MECHAN-
ICAL/PEDAL - REMOVAL). (Fig. 47).
(4) Remove the nuts from the booster mounting
studs (Fig. 47).
(5) Remove the booster and gasket from front cowl
panel.
INSTALLATION
(1) Guide the booster studs into the cowl panel
holes and seat the booster on the panel (Fig. 47).(2) Install and tighten new booster attaching nuts
to 28 N´m (250 in. lbs.).
(3) Install the booster push rod on brake pedal and
install clip (Fig. 47).
(4) Install the booster check valve if removed and
connect the vacuum hose to the check valve.
(5) Install the master cylinder. (Refer to 5 -
BRAKES/HYDRAULIC/MECHANICAL/MASTER
CYLINDER - INSTALLATION).
(6) Fill and bleed the brake system. (Refer to 5 -
BRAKES - STANDARD PROCEDURE).
HYDRO-BOOST BRAKE
BOOSTER
DIAGNOSIS AND TESTING - HYDRAULIC
BOOSTER
The hydraulic booster uses hydraulic pressure from
the power steering pump. Before diagnosing a
booster problem, first verify the power steering pump
is operating properly. Perform the following checks.
²Check the power steering fluid level.
²Check the brake fluid level.
²Check all power steering hoses and lines for
leaks and restrictions.
²Check power steering pump pressure.
NOISES
The hydraulic booster unit will produce certain
characteristic booster noises. The noises may occur
when the brake pedal is used in a manner not asso-
ciated with normal braking or driving habits.
Fig. 47 POWER BRAKE BOOSTER
1 - MOUNTING NUT
2 - POWER BRAKE BOOSTER
DRBRAKES - BASE 5 - 25
ADJUSTABLE PEDAL MOTOR (Continued)

HISSING
A hissing noise may be noticed when above normal
brake pedal pressure is applied, 40 lbs. or above. The
noise will be more noticeable if the vehicle is not
moving. The noise will increase with the brake pedal
pressure and an increase of system operating temper-
ature.
CLUNK-CHATTER-CLICKING
A clunk-chatter-clicking may be noticed when the
brake pedal is released quickly, after above normal
brake pedal pressure is applied 50-100 lbs..
BOOSTER FUNCTION TEST
With the engine off depress the brake pedal several
times to discharge the accumulator. Then depress the
brake pedal using 40 lbs. of force and start the
engine. The brake pedal should fall and then push
back against your foot. This indicates the booster is
operating properly.
ACCUMULATOR LEAKDOWN
(1) Start the engine, apply the brakes and turn the
steering wheel from lock to lock. This will ensure the
accumulator is charged. Turn off the engine and let
the vehicle sit for one hour. After one hour there
should be at least two power assisted brake applica-
tion with the engine off. If the system does not retain
a charge the booster must be replaced.
(2) With the engine off depress the brake pedal
several times to discharge the accumulator. Grasp
the accumulator and see if it wobbles or turns. If it
does the accumulator has lost a gas charge and the
booster must be replaced.
SEAL LEAKAGE
If the booster leaks from any of the seals the
booster assembly must be replaced (Fig. 48).²INPUT ROD SEAL:Fluid leakage from rear
end of the booster.
²PISTON SEAL:Fluid leakage from vent at
front of booster.
²HOUSING SEAL:Fluid leakage between hous-
ing and housing cover.
²SPOOL VALVE SEAL:Fluid leakage near
spool plug.
²RETURN PORT FITTING SEAL:Fluid leak-
age from port fitting.
HYDRAULIC BOOSTER DIAGNOSIS CHART
CONDITION POSSIBLE CAUSES CORRECTION
Slow Brake Pedal Return 1. Excessive seal friction in booster. 1. Replace booster.
2. Faulty spool valve action. 2. Replace booster.
3. Restriction in booster return hose. 3. Replace hose.
4. Damaged input rod. 4. Replace booster.
Excessive Brake Pedal
Effort.1. Internal or external seal leakage. 1. Replace booster.
2. Faulty steering pump. 2. Replace pump.
Fig. 48 Hydraulic Booster Seals
1 - PUMP
2 - GEAR
3 - INPUT SEAL
4 - HOUSING SEAL
5 - ACCUMULATOR SEAL
6 - PISTON SEAL
7 - SPOOL PLUG SEAL
8 - RETURN
5 - 26 BRAKES - BASEDR
HYDRO-BOOST BRAKE BOOSTER (Continued)

CONDITION POSSIBLE CAUSES CORRECTION
Brakes Self Apply 1. Dump valve faulty. 1. Replace booster.
2. Contamination in hydraulic
system.2. Flush hydraulic system and replace
booster.
3. Restriction in booster return hose. 3. Replace hose.
Booster Chatter, Pedal
Vibration1. Slipping pump belt. 1. Replace power steering belt.
2. Low pump fluid level. 2. Fill pump and check for leaks.
Grabbing Brakes 1. Low pump flow. 1. Test and repair/replace pump.
2. Faulty spool valve action. 2. Replace booster.
STANDARD PROCEDURE - BLEEDING
The hydraulic booster is generally self-bleeding,
this procedure will normally bleed the air from the
booster. Normal driving and operation of the unit will
remove any remaining trapped air.
(1) Fill power steering pump reservoir.
(2) Disconnect fuel shutdown relay and crank the
engine for several seconds, Refer to Fuel System for
relay location and WARNING.
(3) Check fluid level and add if necessary.
(4) Connect fuel shutdown relay and start the
engine.
(5) Turn the steering wheel slowly from lock to
lock twice.
(6) Stop the engine and discharge the accumulator
by depressing the brake pedal 5 times.
(7) Start the engine and turn the steering wheel
slowly from lock to lock twice.
(8) Turn off the engine and check fluid level and
add if necessary.
NOTE: If fluid foaming occurs, wait for foam to dis-
sipate and repeat steps 7 and 8.
REMOVAL
NOTE: If the booster is being replaced because the
power steering fluid is contaminated, flush the
power steering system before replacing the booster.
(1) With engine off depress the brake pedal 5
times to discharge the accumulator.
(2) Remove brake lines from master cylinder.
(3) Remove mounting nuts from the master cylin-
der.
(4) Remove the bracket from the hydraulic booster
lines and master cylinder mounting studs.
(5) Remove the master cylinder.
(6) Remove the return hose and the two pressure
lines from the hydraulic booster (Fig. 49).(7) Remove the booster push rod clip, washer and
rod remove from the brake pedal.
(8) Remove the mounting nuts from the hydraulic
booster and remove the booster.INSTALLATION
(1) Install the hydraulic booster and tighten the
mounting nuts to 28 N´m (21 ft. lbs.).
(2) Install the booster push rod, washer and clip
onto the brake pedal.
(3) Install the master cylinder on the mounting
studs. and tighten the mounting nuts to 23 N´m (17
ft. lbs.).
(4) Install the brake lines to the master cylinder
and tighten to 19-200 N´m (170-200 in. lbs.).
(5) Install the hydraulic booster line bracket onto
the master cylinder mounting studs.
(6) Install the master cylinder mounting nuts and
tighten to 23 N´m (17 ft. lbs.).
Fig. 49 HYDRO-BOOST UNIT
1 - INLET HOSE
2 - HYDRO-BOOST UNIT
3 - MASTER CYLINDER UNIT
4 - RETURN HOSE
5 - OUTLET HOSE
DRBRAKES - BASE 5 - 27
HYDRO-BOOST BRAKE BOOSTER (Continued)

CLUTCH
TABLE OF CONTENTS
page page
CLUTCH
DESCRIPTION..........................1
OPERATION............................1
WARNING.............................2
DIAGNOSIS AND TESTING................2
SPECIFICATIONS........................6
CLUTCH DISC
REMOVAL.............................6
INSTALLATION..........................6
CLUTCH HOUSING
DIAGNOSIS AND TESTING................8
REMOVAL.............................10
INSTALLATION.........................10
CLUTCH RELEASE BEARING
REMOVAL.............................11
INSTALLATION.........................11FLYWHEEL
DIAGNOSIS AND TESTING................11
REMOVAL.............................12
DISASSEMBLY.........................12
ASSEMBLY............................12
INSTALLATION.........................12
PILOT BEARING
REMOVAL.............................12
INSTALLATION.........................12
LINKAGE
REMOVAL.............................13
INSTALLATION.........................13
CLUTCH PEDAL POSITION SWITCH
DESCRIPTION.........................14
OPERATION...........................14
DIAGNOSIS AND TESTING................14
CLUTCH
DESCRIPTION
The clutch mechanism consists of a flywheel, a sin-
gle, dry-type disc, and a diaphragm style clutch cover
(Fig. 1). A hydraulic linkage is used to operate the
clutch release bearing and fork. The flywheel is
bolted to the rear flange of the crankshaft. The
clutch pressure plate is bolted to the flywheel with
the clutch disc located between these two compo-
nents. The clutch system provides the mechanical,
but still easily detachable, link between the engine
and the transmission. The system is designed to
ensure that the full torque output of the engine is
transfered to the transmission while isolating the
transmission from the engine firing pulses to mini-
mize concerns such as gear rattle.
OPERATION
Leverage, clamping force and friction are what
make the clutch work. The disc serves as the friction
element and a diaphragm spring and pressure plate
provide the clamping force. The clutch pedal, hydrau-
lic linkage, release lever and bearing provide the
leverage.
The clutch master cylinder push rod is connected
to the clutch pedal. When the clutch pedal is
depressed, the slave cylinder is operated by the
clutch master cylinder mounted on the dash panel.
The release fork is actuated by the hydraulic slave
cylinder mounted on the transmission housing. Therelease bearing is operated by a release fork pivoting
on a ball stud mounted in the transmission housing.
The release bearing then depresses the pressure
plate spring fingers, releasing pressure on the clutch
disc and allowing the engine crankshaft to spin inde-
pendently of the transmission input shaft (Fig. 2).
Fig. 1 ENGINE POWERFLOW
DRCLUTCH 6 - 1

COOLING
TABLE OF CONTENTS
page page
COOLING
DESCRIPTION
DESCRIPTION - COOLING SYSTEM FLOW
3.7L/4.7L ENGINE......................1
DESCRIPTION - COOLING SYSTEM FLOW -
5.9L ENGINE..........................1
DESCRIPTIONÐCOOLING SYSTEM FLOW -
5.9L DIESEL..........................2
DESCRIPTION - HOSE CLAMPS...........3
OPERATION
OPERATIONÐCOOLING SYSTEM.........3
OPERATIONÐHOSE CLAMPS............5
DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTINGÐON-BOARD
DIAGNOSTICS (OBD)...................5
DIAGNOSIS AND TESTINGÐCOOLING
SYSTEM - TESTING FOR LEAKS..........5
DIAGNOSIS AND TESTING - COOLING
SYSTEM DIESEL ENGINE................7
DIAGNOSIS AND TESTING - PRELIMINARY
CHECKS............................10
STANDARD PROCEDURE
STANDARD PROCEDURE - COOLANT
LEVEL CHECK........................17STANDARD PROCEDURE - COOLING
SYSTEM CLEANING/REVERSE FLUSHING . . 17
STANDARD PROCEDUREÐDRAINING
COOLING SYSTEM 3.7L/4.7L/5.7L ENGINE . . 18
STANDARD PROCEDURE - REFILLING
COOLING SYSTEM 3.7L/4.7L/5.7L ENGINE . . 18
STANDARD PROCEDUREÐDRAINING
COOLING SYSTEM 5.9L/8.0L ENGINE......18
STANDARD PROCEDUREÐREFILLING
COOLING SYSTEM 5.9L/8.0L ENGINE......18
STANDARD PROCEDUREÐDRAINING
COOLING SYSTEM 5.9L DIESEL ENGINE . . . 19
STANDARD PROCEDUREÐREFILLING
COOLING SYSTEM 5.9L DIESEL ENGINE . . . 19
STANDARD PROCEDURE - ADDING
ADDITIONAL COOLANT.................19
SPECIFICATIONS
TORQUE............................20
SPECIFICATIONS -....................20
SPECIAL TOOLS
COOLING...........................20
ACCESSORY DRIVE......................22
ENGINE...............................35
TRANSMISSION.........................72
COOLING
DESCRIPTION
DESCRIPTION - COOLING SYSTEM FLOW
3.7L/4.7L ENGINE
The cooling system regulates engine operating tem-
perature. It allows the engine to reach normal oper-
ating temperature as quickly as possible. It also
maintains normal operating temperature and pre-
vents overheating.
The cooling system provides a means of heating
the passenger compartment and cooling the auto-
matic transmission fluid (if equipped). The cooling
system is pressurized and uses a centrifugal water
pump to circulate coolant through the system and a
coolant deaeration and reserve system that utilizes a
pressurized degas bottle (hot bottle).
An optional factory installed maximum duty cool-
ing package is available on most models. This pack-
age will provide additional cooling capacity forvehicles used under extreme conditions such as
trailer towing in high ambient temperatures (Fig. 1).
DESCRIPTION - COOLING SYSTEM FLOW -
5.9L ENGINE
The cooling system regulates engine operating tem-
perature. It allows the engine to reach normal oper-
ating temperature as quickly as possible. It also
maintains normal operating temperature and pre-
vents overheating.
The cooling system also provides a means of heat-
ing the passenger compartment and cooling the auto-
matic transmission fluid (if equipped). The cooling
system uses a coolant recovery / reserve system that
utilizes an ambient overflow bottle.
An optional factory installed maximum duty cool-
ing package is available on most models. This pack-
age will provide additional cooling capacity for
vehicles used under extreme conditions such as
trailer towing in high ambient temperatures (Fig. 2).
DRCOOLING 7 - 1

DESCRIPTIONÐCOOLING SYSTEM FLOW -
5.9L DIESEL
The diesel engine cooling system consists of :
²Cross-flow radiator
²Belt driven water pump
²Belt driven mechanical cooling fan
²Electronic viscous fan drive
²Fan shroud
²Radiator pressure cap²Vertically mounted thermostat
²Coolant reserve/recovery system
²Transmission oil cooler
²Coolant
Coolant flow circuits for the 5.9L diesel engine are
shown in (Fig. 3).
Fig. 1 Engine Cooling System Flow - 3.7L/4.7L
1 - LH CYL. HEAD
2 - BLEED
3 - THERMOSTAT LOCATION
4 - RH CYL. HEAD
5 - RH BANK CYL. BLOCK6 - LH BANK CYL. BLOCK
7 - COOLANT TEMP. SENSOR
8 - FROM HEATER CORE
9 - TO HEATER CORE
7 - 2 COOLINGDR
COOLING (Continued)

DESCRIPTION - HOSE CLAMPS
The cooling system utilizes spring type hose
clamps. If a spring type clamp replacement is neces-
sary, replace with the original Mopartequipment
spring type clamp.
CAUTION: A number or letter is stamped into the
tongue of constant tension clamps. If replacement
is necessary, use only a original equipment clamp
with matching number or letter and ensure the
clamp has the same size width (Fig. 4).
OPERATION
OPERATIONÐCOOLING SYSTEM
The cooling system regulates engine operating tem-
perature. It allows the engine to reach normal oper-
ating temperature as quickly as possible. It also
maintains normal operating temperature and pre-
vents overheating.
The cooling system also provides a means of heat-
ing the passenger compartment and cooling the auto-
matic transmission fluid (if equipped). The cooling
Fig. 2 ENGINE COOLING SYSTEM FLOW - 5.9L
1 - HEATER
2 - BYPASS*3 - CROSSFLOW RADIATOR
4 - THERMOSTAT LOCATION
DRCOOLING 7 - 3
COOLING (Continued)

Fig. 3 Cooling System CirculationÐDiesel Engine
7 - 4 COOLINGDR
COOLING (Continued)

system is pressurized and uses a centrifugal water
pump to circulate coolant throughout the system.
5.9L, 5.9L Diesel, and 8.0L engines utilize an
ambient overflow bottle for coolant recovery/reserve.
The 3.7L and 4.7L engines utilize a pressurized
degas bottle for coolant deaeration and reserve. This
degas bottle has coolant flowing through it continu-
ously, supplied by a vent in the hot side radiator
tank and returning to the heater return hose.
An optional factory installed maximum duty cool-
ing package is available on most models. This pack-
age will provide additional cooling capacity for
vehicles used under extreme conditions such as
trailer towing in high ambient temperatures.
OPERATIONÐHOSE CLAMPS
The spring type hose clamp applies constant ten-
sion on a hose connection. To remove a spring type
hose clamp, only use constant tension clamp pliers
designed to compress the hose clamp.
DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTINGÐON-BOARD
DIAGNOSTICS (OBD)
COOLING SYSTEM RELATED DIAGNOSTICS
The Engine Control Module (ECM) has been pro-
grammed to monitor certain cooling system compo-
nents:
²If the engine has remained cool for too long a
period, such as with a stuck open thermostat, a Diag-
nostic Trouble Code (DTC) can be set.²If an open or shorted condition has developed in
the electronically controlled viscous fan clutch circuit,
a Diagnostic Trouble Code (DTC) can be set.
²If fan speed is not detected a DTC will be set.
²Coolant temperature sensor circuit problems can
set a DTC.
If the problem is sensed in a monitored circuit
often enough to indicated an actual problem, a DTC
is stored. The DTC will be stored in the ECM mem-
ory for eventual display to the service technician.
(Refer to 25 - EMISSIONS CONTROL - DESCRIP-
TION).
ACCESSING DIAGNOSTIC TROUBLE CODES
To read DTC's and to obtain cooling system data,
(Refer to 25 - EMISSIONS CONTROL - DESCRIP-
TION).
ERASING TROUBLE CODES
After the problem has been repaired, use the
DRBIIItscan tool to erase a DTC. Refer to the
appropriate Powertrain Diagnostic Procedures ser-
vice information for operation of the DRBIIItscan
tool.
DIAGNOSIS AND TESTINGÐCOOLING SYSTEM
- TESTING FOR LEAKS
ULTRAVIOLET LIGHT METHOD
A leak detection additive is available through the
parts department that can be added to cooling sys-
tem. The additive is highly visible under ultraviolet
light (black light). Pour one ounce of additive into
cooling system. Place heater control unit in HEAT
position. Start and operate the engine until the radi-
ator upper hose is warm to the touch. Aim the com-
mercially available black light tool at the components
to be checked. If leaks are present, the black light
will cause the additive to glow a bright green color.
The black light can be used in conjunction with a
pressure tester to determine if any external leaks
exist (Fig. 5).
PRESSURE TESTER METHOD
The engine should be at normal operating temper-
ature. Recheck the system cold if the cause of coolant
loss is not located during the warm engine examina-
tion.
WARNING: HOT, PRESSURIZED COOLANT CAN
CAUSE INJURY BY SCALDING.
Carefully remove the radiator pressure cap from
the filler neck and check the coolant level. Push
down on the cap to disengage it from the stop tabs.
Wipe the inside of the filler neck and examine the
Fig. 4 Spring Clamp Size Location
1 - SPRING CLAMP SIZE LOCATION
DRCOOLING 7 - 5
COOLING (Continued)

lower inside sealing seat for nicks, cracks, paint, dirt
and solder residue. Inspect the radiator-to- reserve/
overflow tank hose for internal obstructions. Insert a
wire through the hose to be sure it is not obstructed.
Inspect the cams on the outside of the filler neck.
If the cams are damaged, seating of the pressure cap
valve and tester seal will be affected.
Attach pressure tester (7700 or an equivalent) to
radiator filler neck.
Operate the tester pump to apply 103.4 kPa (15
psi) pressure to the system. If the hoses enlarge
excessively or bulges while testing, replace as neces-
sary. Observe the gauge pointer and determine the
condition of the cooling system according to following
criteria:
Holds Steady:If the pointer remains steady for
two minutes, serious coolant leaks are not present in
system. However, there could be an internal leak
that does not appear with normal system test pres-
sure. If it is certain that coolant is being lost and
leaks cannot be detected, inspect for interior leakage
or perform Internal Leakage Test. Refer to INTER-
NAL LEAKAGE INSPECTION.
Drops Slowly:Indicates a small leak or seepage
is occurring. Examine all of the connections for seep-
age or slight leakage with a flashlight. Inspect the
radiator, hoses, gasket edges and heater. Seal the
small leak holes with a Sealer Lubricant (or equiva-
lent). Repair the leak holes and inspect the system
again with pressure applied.Drops Quickly:Indicates that serious leakage is
occurring. Examine the system for external leakage.
If leaks are not visible, inspect for internal leakage.
Large radiator leak holes should be repaired by a
reputable radiator repair shop.
INTERNAL LEAKAGE INSPECTION
Remove the engine oil pan drain plug and drain a
small amount of engine oil. If coolant is present in
the pan, it will drain first because it is heavier than
oil. An alternative method is to operate engine for a
short period to churn the oil. After this is done,
remove the engine dipstick and inspect for water
globules. Also inspect the transmission dipstick for
water globules and transmission fluid cooler for leak-
age.
WARNING: WITH RADIATOR PRESSURE TESTER
TOOL INSTALLED ON RADIATOR, DO NOT ALLOW
PRESSURE TO EXCEED 145 kPa (21 PSI). PRES-
SURE WILL BUILD UP QUICKLY IF A COMBUSTION
LEAK IS PRESENT. TO RELEASE PRESSURE,
ROCK TESTER FROM SIDE TO SIDE. WHEN
REMOVING TESTER, DO NOT TURN TESTER MORE
THAN 1/2 TURN IF SYSTEM IS UNDER PRESSURE.
Operate the engine without the pressure cap on
the radiator until the thermostat opens. Attach a
Pressure Tester to the filler neck. If pressure builds
up quickly it indicates a combustion leak exists. This
is usually the result of a cylinder head gasket leak or
crack in engine. Repair as necessary.
If there is not an immediate pressure increase,
pump the Pressure Tester. Do this until indicated
pressure is within system range of 110 kPa (16 psi).
Fluctuation of the gauge pointer indicates compres-
sion or combustion leakage into cooling system.
Because the vehicle is equipped with a catalytic
converter,do notshort out cylinders to isolate com-
pression leak.
If the needle on dial of the pressure tester does not
fluctuate, race engine a few times to check for an
abnormal amount of coolant or steam. This would be
emitting from exhaust pipe. Coolant or steam from
exhaust pipe may indicate a faulty cylinder head gas-
ket, cracked engine cylinder block or cylinder head.
A convenient check for exhaust gas leakage into
cooling system is provided by a commercially avail-
able Block Leak Check tool. Follow manufacturers
instructions when using this product.
COMBUSTION LEAKAGE TESTÐWITHOUT
PRESSURE TESTER
DO NOT WASTE reusable coolant. If the solution
is clean, drain the coolant into a clean container for
reuse.
Fig. 5 Leak Detection Using Black LightÐTypical
1 - TYPICAL BLACK LIGHT TOOL
7 - 6 COOLINGDR
COOLING (Continued)