2003 DODGE RAM engine

REMOVAL
WARNING: BECAUSE OF HIGH SPRING PRES-
SURE, DO NOT ATTEMPT TO DISASSEMBLE AUTO-
MATIC TENSIONER. UNIT IS SERVICED AS AN
ASSEMBLY.
(1) Remove accessory drive belt (Refer to 7 -
COOLING/ACCESSORY DRIVE/DRIVE BELTS -
REMOVAL).
(2) Remove tensioner mounting bolt (Fig. 6) and
remove tensioner.
INSTALLATION
(1) Install tensioner assembly to mounting
bracket. A dowel is located on back of tensioner. Align
this dowel to hole in tensioner mounting bracket.
Tighten bolt to 43 N´m (32 ft. lbs.) torque.
(2) Install drive belt (Refer to 7 - COOLING/AC-
CESSORY DRIVE/DRIVE BELTS - INSTALLA-
TION).
DRIVE BELTS - 3.7L / 4.7L
DIAGNOSIS AND TESTING - ACCESSORY
DRIVE BELT
VISUAL DIAGNOSIS
When diagnosing serpentine accessory drive belts,
small cracks that run across the ribbed surface of the
belt from rib to rib (Fig. 7), are considered normal.
These are not a reason to replace the belt. However,
cracks running along a rib (not across) arenotnor-
mal. Any belt with cracks running along a rib must
be replaced (Fig. 7). Also replace the belt if it has
excessive wear, frayed cords or severe glazing.
Refer to ACCESSORY DRIVE BELT DIAGNOSIS
CHART for further belt diagnosis.
NOISE DIAGNOSIS
Noises generated by the accessory drive belt are
most noticeable at idle. Before replacing a belt to
resolve a noise condition, inspect all of the accessory
drive pulleys for alignment, glazing, or excessive end
play.
Fig. 6 AUTOMATIC BELT TENSIONER DIESEL
ENGINE-TYPICAL
1 - GENERATOR
2 - WATER PUMP
3 - IDLER
4 - POWER STEERING PUMP
5 - AUTOMATIC TENSIONER
6 - A/C COMPRESSOR
Fig. 7 Belt Wear Patterns
1 - NORMAL CRACKS BELT OK
2 - NOT NORMAL CRACKS REPLACE BELT
DRACCESSORY DRIVE 7 - 25
BELT TENSIONERS - 5.9L DIESEL (Continued)

CONDITION POSSIBLE CAUSES CORRECTION
NOISE
(Objectionable squeal, squeak, or
rumble is heard or felt while drive
belt is in operation)1. Incorrect belt tension 1. Inspect/Replace tensioner if
necessary
2. Bearing noise 2. Locate and repair
3. Belt misalignment 3. Align belt/pulley(s)
4. Belt to pulley mismatch 4. Install correct belt
5. Driven component induced
vibration5. Locate defective driven
component and repair
TENSION SHEETING FABRIC
FAILURE
(Woven fabric on outside,
circumference of belt has cracked or
separated from body of belt)1. Tension sheeting contacting
stationary object1. Correct rubbing condition
2. Excessive heat causing woven
fabric to age2. Replace belt
3. Tension sheeting splice has
fractured3. Replace belt
CORD EDGE FAILURE
(Tensile member exposed at edges
of belt or separated from belt body)1. Incorrect belt tension 1. Inspect/Replace tensioner if
necessary
2. Belt contacting stationary object 2. Replace belt
3. Pulley(s) out of tolerance 3. Replace pulley
4. Insufficient adhesion between
tensile member and rubber matrix4. Replace belt
REMOVAL
CAUTION: DO NOT LET TENSIONER ARM SNAP
BACK TO THE FREEARM POSITION, SEVER DAM-
AGE MAY OCCUR TO THE TENSIONER.
Belt tension is not adjustable. Belt adjustment is
maintained by an automatic (spring load) belt ten-
sioner.
(1) Disconnect negative battery cable from battery.
(2) Rotate belt tensioner until it contacts it's stop.
Remove belt, then slowly rotate the tensioner into
the freearm position. (Fig. 8).
INSTALLATION
Belt tension is not adjustable. Belt adjustment is
maintained by an automatic ( spring load ) belt ten-
sioner.
(1) Check condition of all pulleys.CAUTION: When installing the serpentine accessory
drive belt, the belt MUST be routed correctly. If not,
the engine may overheat due to the water pump
rotating in the wrong direction (Fig. 8).
(2) Install new belt (Fig. 8). Route the belt around
all pulleys except the idler pulley. Rotate the ten-
sioner arm until it contacts it's stop position. Route
the belt around the idler and slowly let the tensioner
rotate into the belt. Make sure the belt is seated onto
all pulleys.
(3) With the drive belt installed, inspect the belt
wear indicator (Fig. 9). On 4.7L Engines only, the gap
between the tang and the housing stop (measure-
ment A) must not exceed 24 mm (.94 inches). If the
measurement exceeds this specification replace the
serpentine accessory drive belt.
DRACCESSORY DRIVE 7 - 27
DRIVE BELTS - 3.7L / 4.7L (Continued)

DRIVE BELTS - 5.9L
DIAGNOSIS AND TESTING - ACCESSORY
DRIVE BELT
VISUAL DIAGNOSIS
When diagnosing serpentine accessory drive belts,
small cracks that run across the ribbed surface of the
belt from rib to rib (Fig. 10), are considered normal.
These are not a reason to replace the belt. However,
cracks running along a rib (not across) arenotnor-
mal. Any belt with cracks running along a rib must
be replaced (Fig. 10). Also replace the belt if it has
excessive wear, frayed cords or severe glazing.
Refer to ACCESSORY DRIVE BELT DIAGNOSIS
CHART for further belt diagnosis.
NOISE DIAGNOSIS
Noises generated by the accessory drive belt are
most noticeable at idle. Before replacing a belt to
resolve a noise condition, inspect all of the accessory
drive pulleys for alignment, glazing, or excessive end
play.
Fig. 8 BELT ROUTING 3.7L / 4.7L
1 - GENERATOR PULLEY
2 - ACCESSORY DRIVE BELT
3 - POWER STEERING PUMP PULLEY
4 - CRANKSHAFT PULLEY
5 - IDLER PULLEY
6 - TENSIONER
7 - A/C COMPRESSOR PULLEY
8 - WATER PUMP PULLEY
Fig. 9 Accessory Drive Belt Wear Indicator±4.7L
Engine
1 - AUTOMATIC TENSIONER ASSEMBLY
Fig. 10 Belt Wear Patterns
1 - NORMAL CRACKS BELT OK
2 - NOT NORMAL CRACKS REPLACE BELT
7 - 28 ACCESSORY DRIVEDR
DRIVE BELTS - 3.7L / 4.7L (Continued)

CONDITION POSSIBLE CAUSES CORRECTION
NOISE
(Objectionable squeal, squeak, or
rumble is heard or felt while drive
belt is in operation)1. Incorrect belt tension 1. Inspect/Replace tensioner if
necessary
2. Bearing noise 2. Locate and repair
3. Belt misalignment 3. Align belt/pulley(s)
4. Belt to pulley mismatch 4. Install correct belt
5. Driven component induced
vibration5. Locate defective driven
component and repair
TENSION SHEETING FABRIC
FAILURE
(Woven fabric on outside,
circumference of belt has cracked or
separated from body of belt)1. Tension sheeting contacting
stationary object1. Correct rubbing condition
2. Excessive heat causing woven
fabric to age2. Replace belt
3. Tension sheeting splice has
fractured3. Replace belt
CORD EDGE FAILURE
(Tensile member exposed at edges
of belt or separated from belt body)1. Incorrect belt tension 1. Inspect/Replace tensioner if
necessary
2. Belt contacting stationary object 2. Replace belt
3. Pulley(s) out of tolerance 3. Replace pulley
4. Insufficient adhesion between
tensile member and rubber matrix4. Replace belt
REMOVAL
NOTE: The belt routing schematics are published
from the latest information available at the time of
publication. If anything differs between these sche-
matics and the Belt Routing Label, use the sche-
matics on Belt Routing Label.This label is located in
the engine compartment.
CAUTION: Do not attempt to check belt tension with
a belt tension gauge on vehicles equipped with an
automatic belt tensioner. Refer to Automatic Belt
Tensioner in this group.
Drive belts on these engines are equipped with a
spring loaded automatic belt tensioner (Fig. 11). This
belt tensioner will be used on all belt configurations,
such as with or without power steering or air condi-
tioning. For more information, (Refer to 7 - COOL-
ING/ACCESSORY DRIVE/BELT TENSIONERS -
DESCRIPTION).
(1) Attach a socket/wrench to pulley mounting bolt
of automatic tensioner (Fig. 11).
(2) Rotate tensioner assembly clockwise (as viewed
from front) until tension has been relieved from belt.
(3) Remove belt from idler pulley first.
(4) Remove belt from vehicle.
Fig. 11 Belt Tensioner - 5.9L Gas Engines
1 - IDLER PULLEY
2 - TENSIONER
3 - FAN BLADE
7 - 30 ACCESSORY DRIVEDR
DRIVE BELTS - 5.9L (Continued)

INSTALLATION
CAUTION: When installing the accessory drive belt,
the belt must be routed correctly. If not, engine may
overheat due to water pump rotating in wrong
direction. Refer to (Fig. 12) (Fig. 13) for correct
engine belt routing. The correct belt with correct
length must be used.
(1) Position drive belt over all pulleysexceptidler
pulley. This pulley is located between generator and
A/C compressor.
(2) Attach a socket/wrench to pulley mounting bolt
of automatic tensioner (Fig. 11).
(3) Rotate socket/wrench clockwise. Place belt over
idler pulley. Let tensioner rotate back into place.
Remove wrench. Be sure belt is properly seated on
all pulleys.
(4) Check belt indexing marks (Refer to 7 - COOL-
ING/ACCESSORY DRIVE/BELT TENSIONERS -
DESCRIPTION).
DRIVE BELTS - 5.9L DIESEL
DIAGNOSIS AND TESTINGÐACCESSORY
DRIVE BELT
VISUAL DIAGNOSIS
When diagnosing serpentine accessory drive belts,
small cracks that run across the ribbed surface of the
belt from rib to rib (Fig. 14), are considered normal.
These are not a reason to replace the belt. However,
cracks running along a rib (not across) arenotnor-
mal. Any belt with cracks running along a rib must
be replaced (Fig. 14). Also replace the belt if it has
excessive wear, frayed cords or severe glazing.
Fig. 12 Belt Routing - 5.9L Engines with A/C
1 - GENERATOR PULLEY
2 - A/C PULLEY
3 - POWER STEERING PULLEY
4 - CRANKSHAFT PULLEY
5 - WATER PUMP PULLEY
6 - TENSIONER PULLEY
7 - IDLER PULLEY
Fig. 13 Belt Routing - 5.9L Engines Without A/C
1 - GENERATOR PULLEY
2 - IDLER PULLEY
3 - POWER STEERING PULLEY
4 - CRANKSHAFT PULLEY
5 - WATER PUMP PULLEY
6 - TENSIONER PULLEY
DRACCESSORY DRIVE 7 - 31
DRIVE BELTS - 5.9L (Continued)

NOTE: The engine speed sensor face is very close
to the accessory drive belt. Inspect engine speed
sensor and wire harness for damage when acces-
sory drive belt has been replaced due to failure or
abnormal conditions.
REMOVAL
CAUTION: Do not attempt to check belt tension with
a belt tension gauge on vehicles equipped with an
automatic belt tensioner. Refer to Automatic Belt
Tensioner in this group.
NOTE: The belt routing schematics are published
from the latest information available at the time of
publication. If anything differs between these sche-
matics and the Belt Routing Label, use the sche-
matics on Belt Routing Label.This label is located in
the engine compartment.
Drive belts on diesel engines are equipped with a
spring loaded automatic belt tensioner.displays the
tensioner for vehicles without air conditioning.
This belt tensioner will be used on all belt config-
urations, such as with or without air conditioning.
For more information, (Refer to 7 - COOLING/AC-
CESSORY DRIVE/BELT TENSIONERS - DESCRIP-
TION).
(1) A 1/2 inch square hole is provided in the auto-
matic belt tensioner. Attach a 1/2 inch drive-long
handle ratchet to this hole.
(2) Rotate ratchet and tensioner assembly clock-
wise (as viewed from front) until tension has been
relieved from belt.
(3) Remove belt from water pump pulley first.
(4) Remove belt from vehicle.
INSTALLATION
CAUTION: When installing the accessory drive belt,
the belt must be routed correctly. If not, engine mayoverheat due to water pump rotating in wrong
direction. Refer to (Fig. 15) for correct engine belt
routing. The correct belt with correct length must
be used.
(1) Position drive belt over all pulleysexcept
water pump pulley.
(2) Attach a 1/2 inch ratchet to tensioner.
(3) Rotate ratchet and belt tensioner clockwise.
Place belt over water pump pulley. Let tensioner
rotate back into place. Remove ratchet. Be sure belt
is properly seated on all pulleys.
Fig. 15 Belt Routing±5.9L Diesel Engine
1 - GENERATOR PULLEY
2 - WATER PUMP PULLEY
3 - IDLER PULLEY
4 - POWER STEERING PUMP PULLEY
5 - RADIATOR FAN PULLEY
6 - CRANKSHAFT PULLEY
7 - AUTOMATIC TENSIONER
8 - A/C COMPRESSOR PUMP PULLEY
7 - 34 ACCESSORY DRIVEDR
DRIVE BELTS - 5.9L DIESEL (Continued)

ENGINE
TABLE OF CONTENTS
page page
COOLANT
DESCRIPTION
DESCRIPTION - ENGINE COOLANT.......36
DESCRIPTION - HOAT COOLANT.........37
OPERATION...........................38
COOLANT RECOVERY CONTAINER-5.9L
DESCRIPTION.........................38
OPERATION...........................38
REMOVAL.............................38
INSTALLATION.........................38
COOLANT DEGAS CONTAINER-3.7L/4.7L
DESCRIPTION.........................38
OPERATION...........................38
REMOVAL.............................39
INSTALLATION.........................39
RADIATOR FAN
REMOVAL.............................39
CLEANING............................40
INSPECTION..........................40
INSTALLATION.........................40
RADIATOR FAN - 5.9L DIESEL
REMOVAL.............................41
CLEANING............................41
INSPECTION..........................41
INSTALLATION.........................41
ENGINE BLOCK HEATER
DESCRIPTION.........................42
OPERATION...........................42
DIAGNOSIS AND TESTING Ð ENGINE BLOCK
HEATER ............................42
REMOVAL.............................43
INSTALLATION.........................43
ENGINE BLOCK HEATER - 5.9L DIESEL
DESCRIPTION.........................43
OPERATION...........................43
REMOVAL.............................43
INSTALLATION.........................44
ENGINE COOLANT TEMPERATURE SENSOR
DESCRIPTION.........................44
OPERATION...........................44
REMOVAL.............................44
INSTALLATION.........................47
ENGINE COOLANT THERMOSTAT- 5.7L/5.9L
DESCRIPTION.........................47
OPERATION...........................48
DIAGNOSIS AND TESTINGÐTHERMOSTAT . . . 48
REMOVAL.............................48
INSTALLATION.........................49
ENGINE COOLANT THERMOSTAT - 3.7L/4.7L
DESCRIPTION.........................50OPERATION...........................51
DIAGNOSIS AND TESTINGÐTHERMOSTAT . . . 51
REMOVAL.............................51
INSTALLATION.........................51
ENGINE COOLANT THERMOSTAT - 5.9L
DIESEL
DESCRIPTION.........................52
OPERATION...........................52
DIAGNOSIS AND TESTINGÐTHERMOSTAT . . . 52
REMOVAL.............................53
INSTALLATION.........................53
FAN DRIVE VISCOUS CLUTCH
DESCRIPTION.........................54
OPERATION...........................54
DIAGNOSIS AND TESTING - VISCOUS FAN
DRIVE..............................54
FAN DRIVE VISCOUS CLUTCH - 5.9L DIESEL
DESCRIPTION.........................55
OPERATION...........................55
DIAGNOSIS AND TESTING - ELECTRONICLY
CONTOLLED VISCOUS FAN DRIVE.......56
RADIATOR
DESCRIPTION.........................56
OPERATION...........................56
DIAGNOSIS AND TESTINGÐRADIATOR
COOLANT FLOW......................57
REMOVAL.............................57
CLEANING............................58
INSPECTION..........................58
INSTALLATION.........................58
RADIATOR - 5.9L DIESEL
DESCRIPTION.........................59
OPERATION...........................59
DIAGNOSIS AND TESTINGÐRADIATOR
COOLANT FLOW......................59
REMOVAL.............................59
CLEANING............................60
INSPECTION..........................60
INSTALLATION.........................60
RADIATOR PRESSURE CAP
DESCRIPTION.........................60
OPERATION...........................61
DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTINGÐRADIATOR
CAP-TO-FILLER NECK SEAL.............61
DIAGNOSIS AND TESTING - RADIATOR
CAP................................61
CLEANING............................62
INSPECTION..........................62
DRENGINE 7 - 35

WATER PUMP - 5.9L
DESCRIPTION.........................62
OPERATION...........................62
DIAGNOSIS AND TESTINGÐWATER PUMP . . . 62
REMOVAL.............................63
CLEANING............................64
INSPECTION..........................64
INSTALLATION.........................64
WATER PUMP - 3.7L/4.7L
DESCRIPTION
DESCRIPTIONÐWATER PUMP...........64
DESCRIPTIONÐWATER PUMP BYPASS....64
OPERATION
OPERATIONÐWATER PUMP............64
OPERATIONÐWATER PUMP BYPASS.....65
REMOVAL.............................65
CLEANING............................66
INSPECTION..........................66
INSTALLATION.........................66
WATER PUMP - 5.9L DIESEL
DESCRIPTION.........................67OPERATION...........................67
DIAGNOSIS AND TESTINGÐWATER PUMP . . . 67
REMOVAL.............................67
CLEANING............................67
INSPECTION..........................68
INSTALLATION.........................68
WATER PUMP INLET TUBE - 5.9L
REMOVAL
REMOVAL - WATER PUMP BYPASS HOSE
WITH AIR CONDITIONING...............68
REMOVAL - WATER PUMP BYPASS HOSE
WITHOUT AIR CONDITIONING...........69
INSTALLATION
INSTALLATION - WATER PUMP BYPASS
HOSE WITH AIR CONDITIONING.........70
INSTALLATION - WATER PUMP BYPASS
HOSE WITHOUT AIR CONDITIONING......70
WATER PUMP - 5.7L
REMOVAL.............................70
INSTALLATION.........................71
COOLANT
DESCRIPTION
DESCRIPTION - ENGINE COOLANT
ETHYLENE-GLYCOL MIXTURES
CAUTION: Richer antifreeze mixtures cannot be
measured with normal field equipment and can
cause problems associated with 100 percent ethyl-
ene-glycol.
The use of aluminum cylinder blocks, cylinder
heads and water pumps requires special corrosion
protection. Only MopartAntifreeze/Coolant, 5 year/
100,000Mil;e Formula (ethylene-glycol base coolant
with corrosion inhibitors called HOAT, for Hybrid
Additive Technology) is recommended. This coolant
offers the best engine cooling without corrosion when
mixed with 50% distilled water to obtain a freeze
point of -37ÉC (-35ÉF).
The required ethylene-glycol (antifreeze) and water
mixture depends upon the climate and vehicle oper-
ating conditions. The antifreeze concentrationmust
alwaysbe a minimum of 44 percent, year-round in
all climates.If percentage is lower than 44 per-
cent, engine parts may be eroded by cavitation,
and cooling system components may be
severely damaged by corrosion.Maximum protec-
tion against freezing is provided with a 68% anti-
freeze concentration, which prevents freezing down to-67.7É C (-90É F). A higher percentage will freeze at a
warmer temperature. Also, a higher percentage of
antifreeze can cause the engine to overheat because
the specific heat of antifreeze is lower than that of
water.
Use of 100 percent ethylene-glycol will cause for-
mation of additive deposits in the system, as the cor-
rosion inhibitive additives in ethylene-glycol require
the presence of water to dissolve. The deposits act as
insulation, causing temperatures to rise to as high as
149É C (300É F). This temperature is hot enough to
melt plastic and soften solder. The increased temper-
ature can result in engine detonation. In addition,
100 percent ethylene-glycol freezes at 22É C (-8É F ).
PROPYLENE-GLYCOL MIXTURES
It's overall effective temperature range is smaller
than that of ethylene-glycol. The freeze point of 50/50
propylene-glycol and water is -32É C (-26É F). 5É C
higher than ethylene-glycol's freeze point. The boiling
point (protection against summer boil-over) of propy-
lene-glycol is 125É C (257ÉF)at96.5 kPa (14 psi),
compared to 128É C (263É F) for ethylene-glycol. Use
of propylene-glycol can result in boil-over or freeze-up
on a cooling system designed for ethylene-glycol. Pro-
pylene glycol also has poorer heat transfer character-
istics than ethylene glycol. This can increase cylinder
head temperatures under certain conditions.
Propylene-glycol/ethylene-glycol Mixtures can
cause the destabilization of various corrosion inhibi-
tors, causing damage to the various cooling system
7 - 36 ENGINEDR