2003 DODGE RAM app

WARNING: DO NOT REMOVE CYLINDER BLOCK
DRAIN PLUGS OR LOOSEN RADIATOR DRAIN-
COCK WITH SYSTEM HOT AND UNDER PRESSURE.
SERIOUS BURNS FROM COOLANT CAN OCCUR.
Drain sufficient coolant to allow thermostat
removal. (Refer to 7 - COOLING/ENGINE/ENGINE
COOLANT THERMOSTAT - REMOVAL). Remove
accessory drive belt (Refer to 7 - COOLING/ACCES-
SORY DRIVE/DRIVE BELTS - REMOVAL).
Add coolant to radiator to bring level to within 6.3
mm (1/4 in) of the top of the thermostat housing.CAUTION: Avoid overheating. Do not operate
engine for an excessive period of time. Open drain-
cock immediately after test to eliminate boil over.
Start engine and accelerate rapidly three times, to
approximately 3000 rpm while observing coolant. If
internal engine combustion gases are leaking into
cooling system, bubbles will appear in coolant. If bub-
bles do not appear, internal combustion gas leakage
is not present.
DIAGNOSIS AND TESTING - COOLING SYSTEM
DIESEL ENGINE
COOLING SYSTEM DIAGNOSISÐDIESEL ENGINE
CONDITION POSSIBLE CAUSES CORRECTION
TEMPERATURE GAUGE READS
LOWNOTE:
Information on dash cluster is
displayed based on broadcast data
from ECM. DTC will be set for
engine sensor circuit concern.1. Vehicle is equipped with a heavy
duty cooling system.1. None. System operating normally.
2. Thermostat stuck open 2. Inspect and test thermostat.
3. Coolant level low. 3. Fill cooling system. (Refer to 7 -
COOLING - STANDARD
PROCEDURE)
4. Temperature gauge not
functioning correctly.4. Check cluster (Refer to 8 -
ELECTRICAL/INSTRUMENT
CLUSTER - DIAGNOSIS AND
TESTING)
DRCOOLING 7 - 7
COOLING (Continued)

CONDITION POSSIBLE CAUSES CORRECTION
TEMPERATURE GAUGE READS
HIGH. COOLANT MAY OR MAY
NOT BE LEAKING FROM
SYSTEMNOTE:
Information on dash cluster is
displayed based on broadcast data
from ECM. DTC will be set for
engine sensor circuit concern.1. Vehicle overloaded, high ambient
(outside) temperatures with A/C
turned on, stop and go driving or
prolonged operation at idle speeds.1. Temporary condition, repair not
required. Notify customer of vehicle
operation instructions located in
Owners Manual.
2. Temperature gauge not
functioning correctly.2. Check cluster (Refer to 8 -
ELECTRICAL/INSTRUMENT
CLUSTER - DIAGNOSIS AND
TESTING)
3. Air trapped in cooling system 3. Drain cooling system (Refer to 7 -
COOLING - STANDARD
PROCEDURE) and refill (Refer to 7
- COOLING - STANDARD
PROCEDURE)
4. Radiator cap faulty. 4. Replace radiator cap.
5. Plugged A/C or radiator cooling
fins.5. Clean all debris away from A/C
and radiator cooling fins.
6. Coolant mixture incorrect. 6. Drain cooling system (Refer to 7 -
COOLING - STANDARD
PROCEDURE) refill with correct
mixture (Refer to 7 - COOLING -
STANDARD PROCEDURE).
7. Thermostat stuck shut. 7. Inspect and test thermostat.
Replace thermostat if necessary.
8. Bug screen or winter front being
used.8. Remove bug screen or winter
front.
9. Electronically controlled viscous
fan drive not operating properly.9. Check viscous fan (Refer to 7 -
COOLING/ENGINE/FAN DRIVE
VISCOUS CLUTCH - DIAGNOSIS
AND TESTING)
10. Cylinder head gasket leaking. 10. Check for leaking head gaskets
(Refer to 7 - COOLING -
DIAGNOSIS AND TESTING).
11. Heater core leaking. 11. Replace heater core.
12. Cooling system hoses leaking. 12. Tighten clamps or Replace
hoses.
13. Brakes dragging. 13. Check brakes. (Refer to 5 -
BRAKES/HYDRAULIC/
MECHANICAL - DIAGNOSIS AND
TESTING)
14. Accessory drive belt. 14. Inspect. Replace as necessary.
15. Water Pump. 15. Inspect and replace as
necessary.
7 - 8 COOLINGDR
COOLING (Continued)

CONDITION POSSIBLE CAUSES CORRECTION
TEMPERATURE GAUGE READING
INCONSISTENT (ERRATIC,
CYCLES OR FLUCTUATES)NOTE:
Information on dash cluster is
displayed based on broadcast data
from ECM. DTC will be set for
engine sensor circuit concern.1. Heavy duty cooling system,
extreme cold ambient (outside)
temperature or heater blower motor
in high position.1. None. System operating normally.
2. Temperature gauge or sensor
defective.2. Check cluster or engine coolant
temp sensor (Refer to 8 -
ELECTRICAL/INSTRUMENT
CLUSTER - DIAGNOSIS AND
TESTING)
3. Temporary heavy usage or load. 3. None. Normal condition.
4. Air trapped in cooling system. 4. Fill cooling system (Refer to 7 -
COOLING - STANDARD
PROCEDURE).
5. Water pump 5. Replace water pump.
6. Air leak on suction side of water
pump.6. Check for leak. (Refer to 7 -
COOLING - DIAGNOSIS AND
TESTING)
RADIATOR CAP LEAKING STEAM
AND /OR COOLANT INTO
RESERVOIR BOTTLE.
(TEMPERATURE GAUGE MAY
READ HIGH)1. Radiator cap defective. 1. Replace radiator cap.
2. Radiator neck surface damaged. 2. Replace radiator.
HOSE OR HOSES COLLAPSE
WHEN ENGINE IS COOLING.1. Vacuum created in cooling
system on engine cool-down is not
being relieved through coolant
reservoir/overflow system.1. Replace radiator cap, check vent
hose between radiator and reservoir
bottle for blockage also check
reservoir bottle vent for blockage.
NOISY FAN 1. Fan blade(s) loose, damaged. 1. Replace fan blade assembly.
2. Electronically controlled viscous
fan drive.2. None. Normal condition.
3. Fan blades striking surrounding
objects.3. Locate contact point and repair
as necessary.
4. Electronically controlled viscous
fan drive bearing.4. Check viscous fan (Refer to 7 -
COOLING/ENGINE/FAN DRIVE
VISCOUS CLUTCH - DIAGNOSIS
AND TESTING)
5. Electronically controlled viscous
fan stuck on5. Check viscous fan (Refer to 7 -
COOLING/ENGINE/FAN DRIVE
VISCOUS CLUTCH - DIAGNOSIS
AND TESTING)
6. Obstructed air flow through
radiator.6. Remove obstruction.
DRCOOLING 7 - 9
COOLING (Continued)

CONDITION POSSIBLE CAUSES CORRECTION
INADEQUATE AIR CONDITIONER
PERFORMANCE (COOLING
SYSTEM SUSPECTED)1. Radiator and/or A/C condenser
air flow obstructed.1. Remove obstruction and/or clean.
2. Electronically controlled viscous
fan drive not working.2. Check fan drive. (Refer to 7 -
COOLING/ENGINE/FAN DRIVE
VISCOUS CLUTCH - DIAGNOSIS
AND TESTING)
3. Air seals around radiator
damaged or missing.3. Inspect air seals, repair or
replace as necessary.
INADEQUATE HEATER
PERFORMANCE. GAUGE MAY OR
MAY NOT READ LOW.1. Heavy duty cooling system, and
cooler ambient temperatures.1. None. Normal condition.
2. Obstruction in heater hoses. 2. Remove hoses, remove
obstruction.
3. Electronically controlled viscous
fan stuck onCheck fan drive. (Refer to 7 -
COOLING/ENGINE/FAN DRIVE
VISCOUS CLUTCH - DIAGNOSIS
AND TESTING)
4. Water pump damaged. 4. Replace water pump.
HEAT ODOR 1. Damaged or missing drive line
heat shields.1. Repair or replace damaged or
missing heat shields.
2. Electronically controlled viscous
fan drive damaged.2. Check thermal viscous fan drive.
(Refer to 7 - COOLING/ENGINE/
FAN DRIVE VISCOUS CLUTCH -
DIAGNOSIS AND TESTING)
DIAGNOSIS AND TESTING - PRELIMINARY
CHECKS
ENGINE COOLING SYSTEM OVERHEATING
Establish what driving conditions caused the com-
plaint. Abnormal loads on the cooling system such as
the following may be the cause:
²PROLONGED IDLE
²VERY HIGH AMBIENT TEMPERATURE
²SLIGHT TAIL WIND AT IDLE
²SLOW TRAFFIC
²TRAFFIC JAMS
²HIGH SPEED OR STEEP GRADES
Driving techniques that avoid overheating are:
²Idle with A/C off when temperature gauge is at
end of normal range.
²Increasing engine speed for more air flow is rec-
ommended.
TRAILER TOWING:
Consult Trailer Towing section of owners manual.
Do not exceed limits.RECENT SERVICE OR ACCIDENT REPAIR:
Determine if any recent service has been per-
formed on vehicle that may effect the cooling system.
This may be:
²Engine adjustments (incorrect timing)
²Slipping engine accessory drive belt(s)
²Brakes (possibly dragging)
²Changed parts. Incorrect water pump or pump
rotating in wrong direction due to belt not correctly
routed
²Reconditioned radiator or cooling system refill-
ing (possibly under filled or air trapped in system).
²Service to electrically controlled viscous fan
clutch
NOTE: If investigation reveals none of the previous
items as a cause for an engine overheating com-
plaint, refer to COOLING SYSTEM DIAGNOSIS
CHART BELOW.
These charts are to be used as a quick-reference
only. Refer to COOLING SYSTEM DIAGNOSIS
CHART
7 - 10 COOLINGDR
COOLING (Continued)

STANDARD PROCEDURE
STANDARD PROCEDURE - COOLANT LEVEL
CHECK
NOTE: Do not remove radiator cap for routine cool-
ant level inspections. The coolant level can be
checked at coolant recovery bottle or the coolant
degas bottle.
WARNING: DO NOT REMOVE OR LOOSEN THE
RADIATOR CAP WITH THE COOLING SYSTEM HOT
AND UNDER PRESSURE. SERIOUS BURNS FROM
COOLANT OR HIGH PRESSURE STEAM CAN
OCCUR.
The 5.9L, 5.9L Diesel, and 8.0L engine coolant
reserve / overflow system provides a quick method for
determining the coolant level without removing the
radiator pressure cap. With the engine at normal
operating temperature and idling, observe the level
of the coolant on the external level indicator on the
side of the coolant reserve / overflow bottle. The cool-
ant level should be between the MIN and MAX
marks. If the coolant is below the MIN mark, add a
50/50 mixture of antifreeze and water to the bottle
until the level reaches the MIN mark.Do Not Over-
fill the bottle by adding fluid above the MAX
line.This may cause coolant to spill onto the ground
during subsequent vehicle operation.
The 3.7L/4.7L/5.9L engine coolant degas system
provides a quick method for determining the coolant
level with out removing the radiator pressure cap.
With a cold engine, observe the level of coolant in the
degas bottle. The level should be in the COLD FILL
RANGE.DO NOT OVERFILLthe bottle by adding
fluid above the COLD FILL RANGE. This may cause
coolant to spill onto the ground during subsequent
vehicle operation.
STANDARD PROCEDURE - COOLING SYSTEM
CLEANING/REVERSE FLUSHING
CLEANING
Drain the cooling system and refill with water. Run
the engine with the radiator cap installed until the
upper radiator hose is hot. Stop the engine and drain
the water from system. If the water is dirty, fill the
system with water, run the engine and drain the sys-
tem. Repeat this procedure until the water drains
clean.
REVERSE FLUSHING
Reverse flushing of the cooling system is the forc-
ing of water through the cooling system. This is doneusing air pressure in the opposite direction of normal
coolant flow. It is usually only necessary with very
dirty systems with evidence of partial plugging.
REVERSE FLUSHING RADIATOR
Disconnect the radiator hoses from the radiator
inlet and outlet. Attach a section of the radiator hose
to the radiator bottom outlet fitting and insert the
flushing gun. Connect a water supply hose and air
supply hose to the flushing gun.
CAUTION: Internal radiator pressure must not
exceed 138 kPa (20 psi) as damage to radiator may
result.
Allow the radiator to fill with water. When the
radiator is filled, apply air in short blasts. Allow the
radiator to refill between blasts. Continue this
reverse flushing until clean water flows out through
the rear of the radiator cooling tube passages.
REVERSE FLUSHING ENGINE
Drain the cooling system. Remove the thermostat
housing and thermostat. Install the thermostat hous-
ing. Disconnect the radiator upper hose from the
radiator and attach the flushing gun to the hose. Dis-
connect the radiator lower hose from the water pump
and attach a lead-away hose to the water pump inlet
fitting.
CAUTION: On vehicles equipped with a heater water
control valve, be sure the heater control valve is
closed (heat off). This will prevent coolant flow with
scale and other deposits from entering the heater
core.
Connect the water supply hose and air supply hose
to flushing gun. Allow the engine to fill with water.
When the engine is filled, apply air in short blasts,
allowing the system to fill between air blasts. Con-
tinue until clean water flows through the lead away
hose.
Remove the lead away hose, flushing gun, water
supply hose and air supply hose. Remove the thermo-
stat housing and install the thermostat. Install the
thermostat housing with a replacement gasket. Refer
to Thermostat Replacement. Connect the radiator
hoses. Refill the cooling system with the correct anti-
freeze/water mixture. Refer to Refilling the Cooling
System.
CHEMICAL CLEANING
In some instances, use a radiator cleaner (Mopart
Radiator Kleen or equivalent) before flushing. This
will soften scale and other deposits and aid flushing
operation.
DRCOOLING 7 - 17
COOLING (Continued)

ACCESSORY DRIVE
TABLE OF CONTENTS
page page
BELT TENSIONERS - 3.7L / 4.7L
DESCRIPTION.........................22
OPERATION...........................22
REMOVAL.............................22
INSTALLATION.........................23
BELT TENSIONERS - 5.9L
DESCRIPTION.........................23
OPERATION...........................23
REMOVAL.............................23
INSTALLATION.........................24
BELT TENSIONERS - 5.9L DIESEL
DESCRIPTION.........................24
OPERATION...........................24
REMOVAL.............................25
INSTALLATION.........................25DRIVE BELTS - 3.7L / 4.7L
DIAGNOSIS AND TESTING - ACCESSORY
DRIVE BELT.........................25
REMOVAL.............................27
INSTALLATION.........................27
DRIVE BELTS - 5.9L
DIAGNOSIS AND TESTING - ACCESSORY
DRIVE BELT.........................28
REMOVAL.............................30
INSTALLATION.........................31
DRIVE BELTS - 5.9L DIESEL
DIAGNOSIS AND TESTINGÐACCESSORY
DRIVE BELT.........................31
REMOVAL.............................34
INSTALLATION.........................34
BELT TENSIONERS - 3.7L /
4.7L
DESCRIPTION
Correct drive belt tension is required to ensure
optimum performance of the belt driven engine acces-
sories. If specified tension is not maintained, belt
slippage may cause; engine overheating, lack of
power steering assist, loss of air conditioning capac-
ity, reduced generator output rate, and greatly
reduced belt life.
It is not necessary to adjust belt tension on the
3.7L or 4.7L engine. These engines are equipped with
an automatic belt tensioner (Fig. 1). The tensioner
maintains correct belt tension at all times. Due to
use of this belt tensioner, do not attempt to use a belt
tension gauge on 3.7L or 4.7L engines.
OPERATION
The automatic belt tensioner maintains belt ten-
sion by using internal spring pressure, a pivoting
arm and pulley to press against the drive belt.
REMOVAL
On 3.7L and 4.7L engines, the tensioner is
equipped with an indexing tang on back of ten-
sioner and an indexing stop on tensioner hous-
ing. If a new belt is being installed, tang must
be within approximately 24 mm (.94 inches) ofindexing stop. Belt is considered new if it has
been used 15 minutes or less.
If the above specification cannot be met, check for:
²The wrong belt being installed (incorrect length/
width)
²Worn bearings on an engine accessory (A/C com-
pressor, power steering pump, water pump, idler pul-
ley or generator)
²A pulley on an engine accessory being loose
²Misalignment of an engine accessory
²Belt incorrectly routed.
Fig. 1 AUTOMATIC BELT TENSIONER
1 - AUTOMATIC TENSIONER ASSEMBLY
7 - 22 ACCESSORY DRIVEDR

(5) Remove pulley bolt. Remove pulley from ten-
sioner.
INSTALLATION
(1) Install pulley and pulley bolt to tensioner.
Tighten bolt to 61 N´m (45 ft. lbs.) torque.
(2) Install tensioner assembly to mounting
bracket. An indexing tab is located on back of ten-
sioner. Align this tab to slot in mounting bracket.
Tighten nut to 67 N´m (50 ft. lbs.) torque.
(3) Connect all wiring to ignition coil.
CAUTION: To prevent damage to coil case, coil
mounting bolts must be torqued.
(4) Install coil to coil bracket. If nuts and bolts are
used to secure coil to coil bracket, tighten to 11 N´m
(100 in. lbs.) torque. If coil mounting bracket has
been tapped for coil mounting bolts, tighten bolts to 5
N´m (50 in. lbs.) torque.
(5) Install drive belt. (Refer to 7 - COOLING/AC-
CESSORY DRIVE/DRIVE BELTS - INSTALLA-
TION).
(6) Check belt indexing marks (Fig. 4).
BELT TENSIONERS - 5.9L
DIESEL
DESCRIPTION
Drive belts on all engines are equipped with a
spring loaded automatic belt tensioner (Fig. 5). This
tensioner maintains constant belt tension at all times
and requires no maintenance or adjustment.
CAUTION: Do not attempt to check belt tension with
a belt tension gauge on vehicles equipped with an
automatic belt tensioner.
OPERATION
WARNING: THE AUTOMATIC BELT TENSIONER
ASSEMBLY IS SPRING LOADED. DO NOT ATTEMPT
TO DISASSEMBLE THE TENSIONER ASSEMBLY.
The automatic belt tensioner maintains correct belt
tension using a coiled spring within the tensioner
housing. The spring applies pressure to the tensioner
arm pressing the arm into the belt, tensioning the
belt.
Fig. 4 Tensioner Indexing Marks And Mounting Nut
1 - TENSIONER ASSEMBLY
2 - TENSIONER MOUNTING NUT
3 - INDEXING ARROW
4 - INDEXING MARK
Fig. 5 Belt
1 - GENERATOR
2 - WATER PUMP
3 - IDLER
4 - POWER STEERING PUMP
5 - AUTOMATIC TENSIONER
6 - A/C COMPRESSOR
7 - 24 ACCESSORY DRIVEDR
BELT TENSIONERS - 5.9L (Continued)

CAUTION: Do not use coolant additives that are
claimed to improve engine cooling.
OPERATION
Coolant flows through the engine block absorbing
the heat from the engine, then flows to the radiator
where the cooling fins in the radiator transfers the
heat from the coolant to the atmosphere. During cold
weather the ethylene-glycol or propylene-glycol cool-
ant prevents water present in the cooling system
from freezing within temperatures indicated by mix-
ture ratio of coolant to water.
COOLANT RECOVERY
CONTAINER-5.9L
DESCRIPTION
The coolant reserve/overflow tank is mounted on
top of the fan shroud, and is made of high tempera-
ture plastic (Fig. 1).
OPERATION
The coolant reserve/overflow system works in con-
junction with the radiator pressure cap. It utilizes
thermal expansion and contraction of coolant to keep
coolant free of trapped air. It provides a volume for
expansion and contraction of coolant. It also providesa convenient and safe method for checking coolant
level and adjusting level at atmospheric pressure.
This is done without removing the radiator pressure
cap. The system also provides some reserve coolant
to the radiator to cover minor leaks and evaporation
or boiling losses.
As the engine cools, a vacuum is formed in the
cooling system of both the radiator and engine. Cool-
ant will then be drawn from the coolant tank and
returned to a proper level in the radiator.
REMOVAL
(1) Remove recovery hose from radiator.
(2) Remove the coolant container to fan shroud
mounting bolt.
(3) Tilt the container backward towards the engine
to disengage the mounting pin locking features and
lift the container away from the fan shroud (Fig. 1).
INSTALLATION
(1) Align the coolant container mounting pins into
the slots on the fan shroud and push the container
onto the fan shroud.
(2) Secure the container to the fan shroud with the
bolt. Tighten to 8.5N´m (75 in-lbs).
NOTE: Ensure that the locking feature on the
mounting pins has engaged.
(3) Connect the recovery hose to the radiator (Fig.
1).
COOLANT DEGAS
CONTAINER-3.7L/4.7L
DESCRIPTION
The coolant degas container is mounted on top of
the fan shroud and is made of high temperatyre plas-
tic (Fig. 2).
OPERATION
The coolant degas system works in parallel with
the radiator. It is fed through a vent line connected
to the top of the radiator inlet tank and returns to
the engine/coolant pump via the heater return hoses.
This plumbing arrangement, together with the inlet
thermostat, provides for constant flow through the
degas container whenever the engine is running. The
air space in the top of the degas container serves sev-
eral functions. It provides a volume for the expansion
of coolant during engine operation. It provides a
space for quick de-aeration of the coolant. Since the
container is the highest point in the cooling system,
any air trapped in the coolant will quickly be trans-
ported to the degas container and be separated out.
Fig. 1 Coolant Recovery Bottle Ð 5.9L
1 - SCREW
2 - COOLANT RECOVERY CONTAINER
3 - RADIATOR/RADIATOR CAP
4 - FAN SHROUD
7 - 38 ENGINEDR
COOLANT (Continued)