2001 DODGE RAM heating

DIAGNOSIS AND TESTING - COOLING SYSTEM
GAS ENGINE
COOLING SYSTEM DIAGNOSISÐGASOLINE ENGINE
CONDITION POSSIBLE CAUSES CORRECTION
TEMPERATURE
GAUGE READS LOW1. Has a Diagnostic Trouble Code (DTC)
been set indicating a stuck open
thermostat?1. (Refer to 25 - EMISSIONS CONTROL -
DESCRIPTION) for On-Board Diagnostics
and DTC information. Replace thermostat
if necessary.
2. Is the temperature sending unit
connected?2. Check the temperature sensor
connector. (Refer to 8 - ELECTRICAL/
INSTRUMENT CLUSTER - SCHEMATIC -
ELECTRICAL) Repair connector if
necessary.
3. Is the temperature gauge operating
OK?3. Check gauge operation. (Refer to 8 -
ELECTRICAL/INSTRUMENT CLUSTER/
ENGINE TEMPERATURE GAUGE -
DESCRIPTION) . Repair as necessary.
4. Coolant level low in cold ambient
temperatures accompanied with poor
heater performance.4. Check coolant level in the coolant
reserve/overflow tank and the radiator.
Inspect system for leaks. Repair leaks as
necessary. Refer to the Coolant section of
the manual text for WARNINGS and
CAUTIONS associated with removing the
radiator cap.
5. Improper operation of internal heater
doors or heater controls.5. Inspect heater and repair as necessary.
(Refer to 24 - HEATING & AIR
CONDITIONING - DIAGNOSIS AND
TESTING) for procedures.
TEMPERATURE
GAUGE READS HIGH
OR THE COOLANT
WARNING LAMP
ILLUMINATES.
COOLANT MAY OR
MAY NOT BE LOST OR
LEAKING FROM THE
COOLING SYSTEM1. Trailer is being towed, a steep hill is
being climbed, vehicle is operated in slow
moving traffic, or engine is being idled
with very high ambient (outside)
temperatures and the air conditioning is
on. Higher altitudes could aggravate
these conditions.1. This may be a temporary condition and
repair is not necessary. Turn off the air
conditioning and attempt to drive the
vehicle without any of the previous
conditions. Observe the temperature
gauge. The gauge should return to the
normal range. If the gauge does not
return to the normal range, determine the
cause for overheating and repair. Refer to
Possible Causes (2-20).
2. Is the temperature gauge reading
correctly?2. Check gauge. (Refer to 8 -
ELECTRICAL/INSTRUMENT CLUSTER -
SCHEMATIC - ELECTRICAL) . Repair as
necessary.
3. Is the temperature warning illuminating
unnecessarily?3. (Refer to 8 - ELECTRICAL/
INSTRUMENT CLUSTER - SCHEMATIC -
ELECTRICAL).
4. Coolant low in coolant reserve/overflow
tank and radiator?4. Check for coolant leaks and repair as
necessary. (Refer to 7 - COOLING -
DIAGNOSIS AND TESTING).
BR/BECOOLING 7 - 7
COOLING (Continued)

CONDITION POSSIBLE CAUSES CORRECTION
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.
TEMPERATURE
GAUGE READING IS
INCONSISTENT
(FLUCTUATES,
CYCLES OR IS
ERRATIC)1. During cold weather operation, with the
heater blower in the high position, the
gauge reading may drop slightly.1. A normal condition. No correction is
necessary.
2. Temperature gauge or engine mounted
gauge sensor defective or shorted. Also,
corroded or loose wiring in this circuit.2. Check operation of gauge and repair if
necessary. (Refer to 8 - ELECTRICAL/
INSTRUMENT CLUSTER - DIAGNOSIS
AND TESTING).
3. Gauge reading rises when vehicle is
brought to a stop after heavy use (engine
still running)3. A normal condition. No correction is
necessary. Gauge should return to normal
range after vehicle is driven.
4. Gauge reading high after re-starting a
warmed up (hot) engine.4. A normal condition. No correction is
necessary. The gauge should return to
normal range after a few minutes of
engine operation.
5. Coolant level low in radiator (air will
build up in the cooling system causing
the thermostat to open late).5. Check and correct coolant leaks. (Refer
to 7 - COOLING - DIAGNOSIS AND
TESTING).
6. Cylinder head gasket leaking allowing
exhaust gas to enter cooling system
causing a thermostat to open late.6. (a) Check for cylinder head gasket
leaks. (Refer to 7 - COOLING -
DIAGNOSIS AND TESTING).
(b) Check for coolant in the engine oil.
Inspect for white steam emitting from the
exhaust system. Repair as necessary.
7. Water pump impeller loose on shaft. 7. Check water pump and replace as
necessary. (Refer to 7 - COOLING/
ENGINE/WATER PUMP - REMOVAL).
8. Loose accessory drive belt. (water
pump slipping)8. (Refer to 7 - COOLING/ACCESSORY
DRIVE/DRIVE BELTS - DIAGNOSIS AND
TESTING). Check and correct as
necessary.
9. Air leak on the suction side of the
water pump allows air to build up in
cooling system causing thermostat to
open late.9. Locate leak and repair as necessary.
BR/BECOOLING 7 - 9
COOLING (Continued)

CONDITION POSSIBLE CAUSES CORRECTION
PRESSURE CAP IS
BLOWING OFF STEAM
AND/OR COOLANT TO
COOLANT TANK.
TEMPERATURE
GAUGE READING MAY
BE ABOVE NORMAL
BUT NOT HIGH.
COOLANT LEVEL MAY
BE HIGH IN COOLANT
RESERVE/OVERFLOW
TANK1. Pressure relief valve in radiator cap is
defective.1. Check condition of radiator cap and
cap seals. (Refer to 7 - COOLING/
ENGINE/RADIATOR PRESSURE CAP -
DIAGNOSIS AND TESTING). Replace
cap as necessary.
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.
7 - 10 COOLINGBR/BE
COOLING (Continued)

CONDITION POSSIBLE CAUSES CORRECTION
NOISY VISCOUS
FAN/DRIVE1. 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.
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/fittings 3. 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.
BR/BECOOLING 7 - 11
COOLING (Continued)

ACCESSORY DRIVE
TABLE OF CONTENTS
page page
BELT TENSIONERS - 3.9L/5.2L/5.9L
DESCRIPTION...........................19
OPERATION.............................19
REMOVAL..............................20
INSTALLATION...........................20
BELT TENSIONERS - 8.0L
DESCRIPTION...........................20
OPERATION.............................20
REMOVAL..............................21
INSTALLATION...........................22
BELT TENSIONERS - 5.9L DIESEL
DESCRIPTION...........................23
OPERATION.............................23
REMOVAL..............................23
INSTALLATION...........................23
DRIVE BELTS - 3.9L/5.2L/5.9L
DIAGNOSIS AND TESTING.................24
ACCESSORY DRIVE BELT................24
REMOVAL..............................26INSTALLATION...........................27
DRIVE BELTS - 8.0L
DIAGNOSIS AND TESTING.................27
ACCESSORY DRIVE BELT................27
REMOVAL..............................30
INSTALLATION...........................30
DRIVE BELTS - 5.9L DIESEL
DIAGNOSIS AND TESTING.................31
ACCESSORY DRIVE BELT................31
REMOVAL..............................33
INSTALLATION...........................34
VACUUM PUMP - 5.9L DIESEL
DESCRIPTION...........................34
OPERATION.............................35
DIAGNOSIS AND TESTING.................35
VACUUM PUMP OUTPUT.................35
REMOVAL..............................35
INSTALLATION...........................37
BELT TENSIONERS - 3.9L/5.2L/
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
3.9L/5.2L or 5.9L engines. 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 3.9L/5.2L or
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.
Fig. 1 Automatic Belt TensionerÐ5.2L and 5.9L
Engines
1 - AUTOMATIC TENSIONER
2 - COIL AND BRACKET
3 - SCREW AND WASHER
BR/BEACCESSORY DRIVE 7 - 19

(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 DriveÐGas EnginesÐ
Typical
1 - WATER PUMP BYPASS HOSE
2 - FAN BLADE ASSEMBLY
3 - VISCOUS FAN DRIVE
4 - WATER PUMP AND PULLEY
BR/BEENGINE 7 - 43
RADIATOR FAN - 3.9L/5.2L/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 Require-
ment: 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.
Fig. 7 Fan Blade/Viscous Fan Drive
1 - THREADED SHAFT
2 - BOLT (4)
3 - FAN BLADE
4 - THREADED NUT
5 - VISCOUS FAN DRIVE
7 - 44 ENGINEBR/BE
RADIATOR FAN - 3.9L/5.2L/5.9L/8.0L (Continued)

(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 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 Require-
ment: 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 -
3.9L/5.2L/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 3.9L and 5.9L gas powered engine has the
block heater located on the right side of engine next
to the oil filter (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
BR/BEENGINE 7 - 45
RADIATOR FAN - 5.9L DIESEL (Continued)