2002 DODGE RAM heating

CONDITION POSSIBLE CAUSES CORRECTION
8. Incorrect coolant concentration 8. Check coolant. (Refer to
LUBRICATION & MAINTENANCE/
FLUID TYPES - DESCRIPTION).
9. Coolant not flowing through
system9. Check for coolant flow at radiator
filler neck with some coolant
removed, engine warm and
thermostat open. Coolant should be
observed flowing through radiator. If
flow is not observed, determine area
of obstruction and repair as
necessary.
10. Radiator or A/C condenser fins
are dirty or clogged.10. Remove insects and debris.
(Refer to 7 - COOLING -
STANDARD PROCEDURE).
11. Radiator core is corroded or
plugged.11. Have radiator re-cored or
replaced.
12. Aftermarket A/C installed
without proper radiator.12. Install proper radiator.
13. Fuel or ignition system
problems.13. Refer to 14 - Fuel System or 8 -
Electrical for diagnosis and testing
procedures.
14. Dragging brakes. 14. Check and correct as
necessary. (Refer to 5 - BRAKES -
DIAGNOSIS AND TESTING) for
correct procedures.
15. Bug screen or cardboard is
being used, reducing airflow.15. Remove bug screen or
cardboard.
16. Thermostat partially or
completely shut.16. Check thermostat operation and
replace as necessary. (Refer to 7 -
COOLING/ENGINE/ENGINE
COOLANT THERMOSTAT -
REMOVAL).
17. Viscous fan drive not operating
properly.17. Check fan drive operation and
replace as necessary. (Refer to 7 -
COOLING/ENGINE/FAN DRIVE
VISCOUS CLUTCH - REMOVAL).
18. Cylinder head gasket leaking. 18. Check for cylinder head gasket
leaks. (Refer to 7 - COOLING -
DIAGNOSIS AND TESTING).
19. Heater core leaking. 19. Check heater core for leaks.
(Refer to 24 - HEATING & AIR
CONDITIONING/PLUMBING -
DIAGNOSIS AND TESTING).
Repair as necessary.
BR/BECOOLING 7 - 9
COOLING (Continued)

CONDITION POSSIBLE CAUSES CORRECTION
COOLANT LOSS TO THE
GROUND WITHOUT PRESSURE
CAP BLOWOFF. GAUGE READING
HIGH OR HOT1. Coolant leaks in radiator, cooling
system hoses, water pump or
engine.1. Pressure test and repair as
necessary. (Refer to 7 - COOLING -
DIAGNOSIS AND TESTING).
DETONATION OR PRE-IGNITION
(NOT CAUSED BY IGNITION
SYSTEM). GAUGE MAY OR MAY
NOT BE READING HIGH1. Engine overheating. 1. Check reason for overheating
and repair as necessary.
2. Freeze point of coolant not
correct. Mixture is too rich or too
lean.2. Check coolant concentration.
(Refer to LUBRICATION &
MAINTENANCE/FLUID TYPES -
DESCRIPTION).
HOSE OR HOSES COLLAPSE
WHILE ENGINE IS RUNNING1. Vacuum created in cooling
system on engine cool-down is not
being relieved through coolant
reserve/overflow system.1. (a) Radiator cap relief valve
stuck. (Refer to 7 - COOLING/
ENGINE/RADIATOR PRESSURE
CAP - DIAGNOSIS AND TESTING).
Replace if necessary
(b) Hose between coolant
reserve/overflow tank and radiator is
kinked. Repair as necessary.
(c) Vent at coolant reserve/overflow
tank is plugged. Clean vent and
repair as necessary.
(d) Reserve/overflow tank is
internally blocked or plugged. Check
for blockage and repair as
necessary.
NOISY VISCOUS FAN/DRIVE 1. Fan blades loose. 1. Replace fan blade assembly.
(Refer to 7 - COOLING/ENGINE/
RADIATOR FAN - REMOVAL)
2. Fan blades striking a surrounding
object.2. Locate point of fan blade contact
and repair as necessary.
3. Air obstructions at radiator or air
conditioning condenser.3. Remove obstructions and/or
clean debris or insects from radiator
or A/C condenser.
4. Thermal viscous fan drive has
defective bearing.4. Replace fan drive. Bearing is not
serviceable. (Refer to 7 - COOLING/
ENGINE/FAN DRIVE VISCOUS
CLUTCH - REMOVAL).
5. A certain amount of fan noise
may be evident on models
equipped with a thermal viscous fan
drive. Some of this noise is normal.5. (Refer to 7 - COOLING/ENGINE/
FAN DRIVE VISCOUS CLUTCH -
DESCRIPTION) for an explanation
of normal fan noise.
BR/BECOOLING 7 - 11
COOLING (Continued)

CONDITION POSSIBLE CAUSES CORRECTION
INADEQUATE HEATER
PERFORMANCE. THERMOSTAT
FAILED IN OPEN POSITION1. Has a Diagnostic trouble Code
(DTC) been set?1. (Refer to 25 - EMISSIONS
CONTROL - DESCRIPTION) for
correct procedures and replace
thermostat if necessary
2. Coolant level low 2. (Refer to 7 - COOLING -
DIAGNOSIS AND TESTING).
3. Obstructions in heater hose/
fittings3. Remove heater hoses at both
ends and check for obstructions
4. Heater hose kinked 4. Locate kinked area and repair as
necessary
5. Water pump is not pumping
water to/through the heater core.
When the engine is fully warmed
up, both heater hoses should be
hot to the touch. If only one of the
hoses is hot, the water pump may
not be operating correctly or the
heater core may be plugged.
Accessory drive belt may be
slipping causing poor water pump
operation.5. (Refer to 7 - COOLING/ENGINE/
WATER PUMP - REMOVAL). If a
slipping belt is detected, (Refer to 7
- COOLING/ACCESSORY
DRIVE/DRIVE BELTS - DIAGNOSIS
AND TESTING). If heater core
obstruction is detected, (Refer to 24
- HEATING & AIR CONDITIONING/
PLUMBING/HEATER CORE -
REMOVAL).
STEAM IS COMING FROM THE
FRONT OF VEHICLE NEAR THE
GRILL AREA WHEN WEATHER IS
WET, ENGINE IS WARMED UP
AND RUNNING, AND VEHICLE IS
STATIONARY. TEMPERATURE
GAUGE IS IN NORMAL RANGE1. During wet weather, moisture
(snow, ice or rain condensation) on
the radiator will evaporate when the
thermostat opens. This opening
allows heated water into the
radiator. When the moisture
contacts the hot radiator, steam
may be emitted. This usually occurs
in cold weather with no fan or
airflow to blow it away.1. Occasional steam emitting from
this area is normal. No repair is
necessary.
COOLANT COLOR 1. Coolant color is not necessarily
an indication of adequate corrosion
or temperature protection. Do not
rely on coolant color for determining
condition of coolant.1. (Refer to LUBRICATION &
MAINTENANCE/FLUID TYPES -
DESCRIPTION). Adjust coolant
mixture as necessary.
COOLANT LEVEL CHANGES IN
COOLANT RESERVE/OVERFLOW
TANK. TEMPERATURE GAUGE IS
IN NORMAL RANGE1. Level changes are to be
expected as coolant volume
fluctuates with engine temperature.
If the level in the tank was between
the FULL and ADD marks at normal
operating temperature, the level
should return to within that range
after operation at elevated
temperatures.1. A normal condition. No repair is
necessary.
7 - 12 COOLINGBR/BE
COOLING (Continued)

ACCESSORY DRIVE
TABLE OF CONTENTS
page page
BELT TENSIONERS - 5.9L
DESCRIPTION.........................19
OPERATION...........................19
REMOVAL.............................19
INSTALLATION.........................20
BELT TENSIONERS - 8.0L
DESCRIPTION.........................20
OPERATION...........................21
REMOVAL.............................21
INSTALLATION.........................22
BELT TENSIONERS - 5.9L DIESEL
DESCRIPTION.........................23
OPERATION...........................23
REMOVAL.............................23
INSTALLATION.........................23
DRIVE BELTS - 5.9L
DIAGNOSIS AND TESTING - ACCESSORY
DRIVE BELT.........................24
REMOVAL.............................26INSTALLATION.........................26
DRIVE BELTS - 8.0L
DIAGNOSIS AND TESTINGÐACCESSORY
DRIVE BELT.........................27
REMOVAL.............................29
INSTALLATION.........................29
DRIVE BELTS - 5.9L DIESEL
DIAGNOSIS AND TESTINGÐACCESSORY
DRIVE BELT.........................30
REMOVAL.............................32
INSTALLATION.........................32
VACUUM PUMP - 5.9L DIESEL
DESCRIPTION.........................33
OPERATION...........................34
DIAGNOSIS AND TESTINGÐVACUUM PUMP
OUTPUT............................34
REMOVAL.............................34
INSTALLATION.........................36
BELT TENSIONERS - 5.9L
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
5.9L engines. These engines are equipped with an
automatic belt tensioner (Fig. 1). The tensioner main-
tains correct belt tension at all times. Due to use of
this belt tensioner, do not attempt to use a belt ten-
sion gauge on 5.9L 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
WARNING: BECAUSE OF HIGH SPRING PRES-
SURE, DO NOT ATTEMPT TO DISASSEMBLE AUTO-
MATIC TENSIONER. UNIT IS SERVICED AS AN
ASSEMBLY (EXCEPT FOR PULLEY).(1) Remove accessory drive belt. (Refer to 7 -
COOLING/ACCESSORY DRIVE/DRIVE BELTS -
REMOVAL).
(2) Disconnect wiring and secondary cable from
ignition coil.
(3) Remove ignition coil from coil mounting
bracket (two bolts). Do not remove coil mounting
bracket from cylinder head.
Fig. 1 Automatic Belt Tensioner - 5.9L Engines
1 - AUTOMATIC TENSIONER
2 - COIL AND BRACKET
3 - SCREW AND WASHER
BR/BEACCESSORY DRIVE 7 - 19

(5) Do not attempt to remove fan/viscous fan drive
assembly from vehicle at this time.
(6) Do not unbolt fan blade assembly (Fig. 6) from
viscous fan drive at this time.
(7) Remove four fan shroud-to-radiator mounting
bolts.(8) Remove fan shroud and fan blade/viscous fan
drive assembly as a complete unit from vehicle.
(9) After removing fan blade/viscous fan drive
assembly,do notplace viscous fan drive in horizon-
tal position. If stored horizontally, silicone fluid in
the viscous fan drive could drain into its bearing
assembly and contaminate lubricant.
CAUTION: Do not remove water pump pulley-to-wa-
ter pump bolts. This pulley is under spring tension.
(10) Remove four bolts securing fan blade assem-
bly to viscous fan drive (Fig. 6).
CAUTION: Some engines equipped with serpentine
drive belts have reverse rotating fans and viscous
fan drives. They are marked with the word
REVERSE to designate their usage. Installation of
the wrong fan or viscous fan drive can result in
engine overheating.
CLEANING
Clean the fan blades using a mild soap and water.
Do not use an abrasive to clean the blades.
INSPECTION
WARNING: DO NOT ATTEMPT TO BEND OR
STRAIGHTEN FAN BLADES IF FAN IS NOT WITHIN
SPECIFICATIONS.
CAUTION: If fan blade assembly is replaced
because of mechanical damage, water pump and
viscous fan drive should also be inspected. These
components could have been damaged due to
excessive vibration.
(1) Remove fan blade assembly from viscous fan
drive unit (four bolts).
(2) Lay fan on a flat surface with leading edge fac-
ing down. With tip of blade touching flat surface,
replace fan if clearance between opposite blade and
surface is greater than 2.0 mm (.090 inch). Rocking
motion of opposite blades should not exceed 2.0 mm
(.090 inch). Test all blades in this manner.
(3) Inspect fan assembly for cracks, bends, loose
rivets or broken welds. Replace fan if any damage is
found.
INSTALLATION
(1) Install fan blade assembly to viscous fan drive.
Tighten bolts (Fig. 6) to 23 N´m (17 ft. lbs.) torque.
(2) Position fan shroud and fan blade/viscous fan
drive assembly to vehicle as a complete unit.
(3) Install fan shroud.
Fig. 5 Using Special Tool 6958 Spanner Wrench
1 - SPECIAL TOOL 6958 SPANNER WRENCH WITH ADAPTER
PINS 8346
2-FAN
Fig. 6 Fan Blade/Viscous Fan Drive - Gas Engines -
Typical
1 - WATER PUMP BYPASS HOSE
2 - FAN BLADE ASSEMBLY
3 - VISCOUS FAN DRIVE
4 - WATER PUMP AND PULLEY
7 - 42 ENGINEBR/BE
RADIATOR FAN - 5.9L/8.0L (Continued)

(4) Install fan blade/viscous fan drive assembly to
water pump shaft (Fig. 6).
(5) Except 8.0L V-10 Engine: Install coolant
reserve/overflow tank to fan shroud. Snaps into posi-
tion.
(6) Install throttle cable to fan shroud.
(7) Connect negative battery cable.
NOTE:
Viscous Fan Drive Fluid Pump Out Requirement:
After installing a new viscous fan drive, bring the
engine speed up to approximately 2000 rpm and
hold for approximately two minutes. This will
ensure proper fluid distribution within the drive.
RADIATOR FAN - 5.9L DIESEL
REMOVAL
CAUTION: If the viscous fan drive is replaced
because of mechanical damage, the cooling fan
blades should also be inspected. Inspect for fatigue
cracks, loose blades, or loose rivets that could
have resulted from excessive vibration. Replace fan
blade assembly if any of these conditions are
found. Also inspect water pump bearing and shaft
assembly for any related damage due to a viscous
fan drive malfunction.
(1) Disconnect the battery negative cables.
(2) Remove the fan shroud mounting bolts. Posi-
tion fan shroud towards engine.
CAUTION: Do not remove the fan pulley bolts. This
pulley is under spring tension.
(3) The thermal viscous fan drive/fan blade assem-
bly is attached (threaded) to the fan hub shaft (Fig.
7). Remove the fan blade/fan drive assembly from fan
pulley by turning the mounting nut clockwise (as
viewed from front). Threads on the viscous fan drive
areLEFT-HAND.A Snap-On 36 MM Fan Wrench
(number SP346 from Snap-On Cummins Diesel Tool
Set number 2017DSP) can be used. Place a bar or
screwdriver between the fan pulley bolts to prevent
pulley from rotating.
(4) Remove the fan shroud and the fan blade/vis-
cous drive as an assembly from vehicle.
(5) Remove fan blade-to-viscous fan drive mount-
ing bolts.
(6) Inspect the fan for cracks, loose rivets, loose or
bent fan blades.
CAUTION: Some engines equipped with serpentine
drive belts have reverse rotating fans and viscous
fan drives. They are marked with the wordREVERSE to designate their usage. Installation of
the wrong fan or viscous fan drive can result in
engine overheating.
CLEANING
Clean the fan blades using a mild soap and water.
Do not use an abrasive to clean the blades.
INSPECTION
WARNING: DO NOT ATTEMPT TO BEND OR
STRAIGHTEN FAN BLADES IF FAN IS NOT WITHIN
SPECIFICATIONS.
CAUTION: If fan blade assembly is replaced
because of mechanical damage, water pump and
viscous fan drive should also be inspected. These
components could have been damaged due to
excessive vibration.
(1) Remove fan blade assembly from viscous fan
drive unit (four bolts).
(2) Lay fan on a flat surface with leading edge fac-
ing down. With tip of blade touching flat surface,
replace fan if clearance between opposite blade and
surface is greater than 2.0 mm (.090 inch). Rocking
motion of opposite blades should not exceed 2.0 mm
(.090 inch). Test all blades in this manner.
(3) Inspect fan assembly for cracks, bends, loose
rivets or broken welds. Replace fan if any damage is
found.
Fig. 7 Fan Blade/Viscous Fan Drive
1 - THREADED SHAFT
2 - BOLT (4)
3 - FAN BLADE
4 - THREADED NUT
5 - VISCOUS FAN DRIVE
BR/BEENGINE 7 - 43
RADIATOR FAN - 5.9L/8.0L (Continued)

INSTALLATION
(1) Install fan blade assembly to viscous fan drive.
Tighten mounting bolts to 23 N´m (17 ft. lbs.) torque.
(2) Position the fan shroud and fan blade/viscous
fan drive to the vehicle as an assembly.
(3) Install viscous fan drive assembly on fan hub
shaft (Fig. 7). Tighten mounting nut to 57 N´m (42 ft.
lbs.) torque.
(4) Install fan shroud bolts into position and
tighten the mounting bolts to 6 N´m (50 in. lbs.)
torque.
(5) Connect the battery negative cables.
NOTE:
Viscous Fan Drive Fluid Pump Out Requirement:
After installing a new viscous fan drive, bring the
engine speed up to approximately 2000 rpm and
hold for approximately two minutes. This will
ensure proper fluid distribution within the drive.
ENGINE BLOCK HEATER - 5.9L
DESCRIPTION
WARNING: DO NOT OPERATE ENGINE UNLESS
BLOCK HEATER CORD HAS BEEN DISCONNECTED
FROM POWER SOURCE AND SECURED IN PLACE.
THE POWER CORD MUST BE SECURED IN ITS
RETAINING CLIPS AND ROUTED AWAY FROM
EXHAUST MANIFOLDS AND MOVING PARTS.
An optional engine block heater is available on all
models. The heater is equipped with a power cord.
The heater is mounted in a core hole of the engine
cylinder block (in place of a freeze plug) with the
heating element immersed in engine coolant. The
cord is attached to an engine compartment compo-
nent with tie-straps.
The 5.9L gas powered engine has the block heater
located on the right side of engine next to the oil fil-
ter (Fig. 8).
OPERATION
The heater warms the engine coolant providing
easier engine starting and faster warm-up in low
temperatures. Connecting the power cord to a
grounded 110-120 volt AC electrical outlet with a
grounded three wire extension cord provides the elec-
tricity needed to heat the element..
REMOVAL
(1) Disconnect battery negative cable.
(2) Drain coolant (Refer to 7 - COOLING - STAN-
DARD PROCEDURE).(3) Remove power cord from heater by unplugging
(Fig. 9).
(4) Loosen (but do not completely remove) the
screw at center of block heater (Fig. 9).
(5) Remove block heater by carefully prying from
side-to-side. Note direction of heating element coil
(up or down). Element coil must be installed correctly
to prevent damage.
INSTALLATION
(1) Clean and inspect the block heater hole.
(2) Install new O-ring seal(s) to heater in gasoline
engines.
(3) Insert block heater into cylinder block.
(4) With heater fully seated, tighten center screw
to 2 N´m (17 in. lbs.).
(5) Fill cooling system with recommended coolant.
(Refer to 7 - COOLING - STANDARD PROCE-
DURE).
(6) Start and warm the engine.
(7) Check block heater for leaks.
Fig. 8 Engine Block Heater
1 - FREEZE PLUG HOLE
2 - BLOCK HEATER
3 - SCREW
4 - POWER CORD (120V AC)
5 - HEATING COIL
6 - OIL FILTER
7 - 44 ENGINEBR/BE
RADIATOR FAN - 5.9L DIESEL (Continued)

ENGINE BLOCK HEATER - 8.0L
DESCRIPTION
An optional engine block heater is available on all
models. The heater is equipped with a power cord.
The heater is mounted in a core hole of the engine
cylinder block (in place of a freeze plug) with the
heating element immersed in engine coolant. The
cord is attached to an engine compartment compo-
nent with tie-straps.
The 8.0L V-10 engine has the block heater located
on the right side of engine next to the engine oil dip-
stick tube (Fig. 10).
WARNING: DO NOT OPERATE ENGINE UNLESS
BLOCK HEATER CORD HAS BEEN DISCONNECTED
FROM POWER SOURCE AND SECURED IN PLACE.
THE POWER CORD MUST BE SECURED IN ITS
RETAINING CLIPS AND ROUTED AWAY FROM
EXHAUST MANIFOLDS AND MOVING PARTS.
OPERATION
The heater warms the engine coolant providing
easier engine starting and faster warm-up in low
temperatures. Connecting the power cord to agrounded 110-120 volt AC electrical outlet with a
grounded three wire extension cord provides the elec-
tricity needed to heat the element..
REMOVAL
(1) Disconnect battery negative cable.
(2) Drain coolant from radiator and cylinder block
(Refer to 7 - COOLING - STANDARD PROCE-
DURE).
(3) Remove power cord from heater by unplugging
(Fig. 11).
(4) Loosen (but do not completely remove) the
screw at center of block heater (Fig. 11).
(5) Remove block heater by carefully prying from
side-to-side. Note direction of heating element coil
(up or down). Element coil must be installed correctly
to prevent damage.
INSTALLATION
(1) Clean and inspect the block heater hole.
(2) Install new O-ring seal(s) to heater in gasoline
engines.
(3) Insert block heater into cylinder block.
(4) With heater fully seated, tighten center screw
to 2 N´m (17 in. lbs.).
Fig. 9 Engine Block Heater
1 - FREEZE PLUG HOLE
2 - BLOCK HEATER
3 - SCREW
4 - POWER CORD (120V AC)
5 - HEATING COIL
6 - OIL FILTER
Fig. 10 Engine Block HeaterÐ8.0L V-10 Engine
1 - FREEZE PLUG HOLE
2 - SCREW
3 - POWER CORD (120V AC)
4 - BLOCK HEATER
5 - HEATING COIL
BR/BEENGINE 7 - 45
ENGINE BLOCK HEATER - 5.9L (Continued)