2001 DODGE RAM heater

STANDARD PROCEDUREÐDRAINING
COOLING SYSTEM 3.9L/5.2L/5.9L/8.0L
ENGINES
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.
DO NOT WASTE reusable coolant. If solution is
clean, drain coolant into a clean container for reuse.
(1) Remove radiator pressure cap.
(2) Loosen radiator petcock.
(3) Remove cylinder block drain plugs. Refer to
(Fig. 7).
STANDARD PROCEDUREÐDRAINING COOLING
SYSTEM 5.9L DIESEL ENGINE
WARNING: DO NOT REMOVE THE CYLINDER
BLOCK DRAIN PLUGS OR LOOSEN THE RADIATOR
DRAIN PLUG WITH SYSTEM HOT AND UNDER
PRESSURE. SERIOUS BURNS FROM COOLANT
CAN OCCUR.
DO NOT WASTE reusable coolant. If the solution
is clean, drain the coolant into a clean container for
reuse.
(1) Start the engine and place the heater control
temperature selector in the Full-On position. Vacuum
is needed to actuate the heater controls.
(2) Turn the ignition off.
(3) Do not remove radiator cap when draining cool-
ant from reserve/overflow tank. Open radiator drain
plug and when tank is empty, remove radiator cap. If
the coolant reserve/overflow tank does not drain,
(Refer to 7 - COOLING - DIAGNOSIS AND TEST-ING). The coolant need not be removed from tank
unless the system is being refilled with fresh mix-
ture.
(4) Remove radiator pressure cap.
STANDARD PROCEDUREÐREFILLING
COOLING SYSTEM 3.9L/5.2L/5.9L/8.0L
ENGINES
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.
DO NOT WASTE reusable coolant. If solution is
clean, drain coolant into a clean container for reuse.
Clean cooling system prior to refilling. (Refer to 7 -
COOLING - STANDARD PROCEDURE).
(1) Install cylinder block drain plugs. Coat the
threads with MopartThread Sealant with Teflon.
(2) Close radiator petcock.
(3) Fill cooling system with a 50/50 mixture of
water and antifreeze.
(4) Fill coolant reserve/overflow tank to FULL
mark on indicator stick.
(5) Start and operate engine until thermostat
opens (upper radiator hose warm to touch).
(6) If necessary, add a 50/50 water and antifreeze
mixture to the coolant reserve/overflow tank. This is
done to maintain coolant level between the FULL
and ADD marks. The level in the reserve/overflow
tank may drop below the ADD mark after three or
four warm-up and cool-down cycles.
STANDARD PROCEDUREÐREFILLING
COOLING SYSTEM 5.9L DIESEL ENGINE
Clean cooling system prior to refilling (Refer to 7 -
COOLING - STANDARD PROCEDURE).
(1) Close radiator drain plug.
CAUTION: Due to the use of the one-way check
valve, the engine must not be operating when refill-
ing the cooling system.
NOTE: The diesel engine is equipped with a one-
way check valve (jiggle pin). The check valve is
used as a servicing feature and will vent air when
the system is being filled. Water pressure (or flow)
will hold the valve closed.
(2) Fill the cooling system with a 50/50 mixture of
water and antifreeze.
Fig. 7 Cylinder Block Drain PlugÐ3.9L/5.2L/5.9L
Engines
1 - BLOCK DRAIN PLUG
BR/BECOOLING 7 - 15
COOLING (Continued)

REVERSE FLUSHING ENGINE
Drain cooling system. Remove thermostat housing
and thermostat. Install thermostat housing. Discon-
nect radiator upper hose from radiator and attach
flushing gun to hose. Disconnect radiator lower hose
from water pump and attach a lead-away hose to
water pump inlet fitting.
CAUTION: On vehicles equipped with a heater water
control valve, be sure heater control valve is closed
(heat off). This will prevent coolant flow with scale
and other deposits from entering heater core.
Connect water supply hose and air supply hose to
flushing gun. Allow engine to fill with water. When
engine is filled, apply air in short blasts, allowing
system to fill between air blasts. Continue until clean
water flows through the lead away hose.
Remove lead away hose, flushing gun, water sup-
ply hose and air supply hose. Remove thermostat
housing and install thermostat. Install thermostat
housing with a replacement gasket. Refer to Thermo-
stat Replacement. Connect radiator hoses. Refill cool-
ing system with correct antifreeze/water mixture.
Refer to Refilling the Cooling System.
CHEMICAL CLEANING
In some instances, use a radiator cleaner (Mopar
Radiator Kleen or equivalent) before flushing. This
will soften scale and other deposits and aid flushing
operation.
CAUTION: Follow manufacturers instructions when
using these products.
STANDARD PROCEDUREÐCOOLANT
SELECTION-ADDITIVES
The presence of aluminum components in the cool-
ing system requires strict corrosion protection. Main-
tain coolant at specified level with a mixture of
ethylene glycol based antifreeze and water. If coolant
becomes contaminated or looses color, drain and flush
cooling system and fill with correctly mixed solution.
CAUTION: Do not use coolant additives that are
claimed to improve engine cooling.
SPECIFICATIONS
TORQUE
DESCRIPTION N´m Ft. In.
Lbs. Lbs
Belt Tensioner Pulley
3.9/5.2/5.9L
EnginesÐBolt 61 45 Ð
Belt Tensioner Pulley 8.0L
EngineÐ
Bolt 88 65 Ð
Belt Tensioner to Mounting
BracketÐ
Bolt 3.9L/5.2L/5.9L Engines 67 50 Ð
Belt Tensioner to Mounting
BracketÐ
Bolt 8.0L Engine 41 30 Ð
Block HeaterÐScrew Gas
Engines2Ð17
Block HeaterÐHex Diesel
Engine43 32 Ð
Fan Shroud to Radiator
MountingÐ
Bolts 6 Ð 50
Heater Hose Fitting at Water
PumpÐ(8.0L) 16 Ð 142
Idler Pulley MountingÐBolts
Gas Engines 61 45 Ð
Radiator MountingÐBolts 11 Ð 95
Thermal Viscous Fan to
HubÐ(Diesel)57 42 Ð
Thermostat HousingÐBolts
3.9/5.2/5.9L 23 Ð 200
Thermostat HousingÐBolts
8.0L25 Ð 220
Thermostat HousingÐBolts
Diesel24 Ð 212
Water Pump MountingÐBolts
Gas Engines 40 30 Ð
Water Pump MountingÐBolts
Diesel24 Ð 212
BR/BECOOLING 7 - 17
COOLING (Continued)

ENGINE
TABLE OF CONTENTS
page page
COOLANT
DESCRIPTION...........................40
OPERATION.............................40
COOLANT RECOVERY CONTAINER - 3.9L/5.2L/
5.9L/5.9L DIESEL
DESCRIPTION...........................41
OPERATION.............................41
REMOVAL..............................41
INSTALLATION...........................41
COOLANT RECOVERY CONTAINER - 8.0L
DESCRIPTION...........................42
OPERATION.............................42
RADIATOR FAN - 3.9L/5.2L/5.9L/8.0L
REMOVAL..............................42
CLEANING..............................43
INSPECTION............................43
INSTALLATION...........................43
RADIATOR FAN - 5.9L DIESEL
REMOVAL..............................44
CLEANING..............................44
INSPECTION............................44
INSTALLATION...........................45
ENGINE BLOCK HEATER - 3.9L/5.2L/5.9L
DESCRIPTION...........................45
OPERATION.............................45
REMOVAL..............................45
INSTALLATION...........................45
ENGINE BLOCK HEATER - 8.0L
DESCRIPTION...........................46
OPERATION.............................46
REMOVAL..............................46
INSTALLATION...........................46
ENGINE BLOCK HEATER - 5.9L DIESEL
DESCRIPTION...........................47
OPERATION.............................47
REMOVAL..............................47
INSTALLATION...........................47
ENGINE COOLANT TEMP SENSOR - 3.9L/5.2L/
5.9L
DESCRIPTION...........................48
OPERATION.............................48
REMOVAL..............................48
INSTALLATION...........................48
ENGINE COOLANT THERMOSTAT - 3.9L/5.2L/
5.9L
DESCRIPTION...........................49
OPERATION.............................49
DIAGNOSIS AND TESTING.................49
THERMOSTAT.........................49REMOVAL..............................49
INSTALLATION...........................50
ENGINE COOLANT THERMOSTAT - 8.0L
DESCRIPTION...........................52
OPERATION.............................52
DIAGNOSIS AND TESTING.................52
THERMOSTAT.........................52
REMOVAL..............................52
INSTALLATION...........................53
ENGINE COOLANT THERMOSTAT - 5.9L
DIESEL
DESCRIPTION...........................54
OPERATION.............................54
DIAGNOSIS AND TESTING.................54
THERMOSTAT.........................54
REMOVAL..............................55
INSTALLATION...........................55
FAN DRIVE VISCOUS CLUTCH - 3.9L/5.2L/5.9L/
8.0L
DESCRIPTION...........................56
OPERATION.............................56
DIAGNOSIS AND TESTING.................56
VISCOUS FAN DRIVE...................56
FAN DRIVE VISCOUS CLUTCH - 5.9L DIESEL
DESCRIPTION...........................57
OPERATION.............................57
DIAGNOSIS AND TESTING.................58
VISCOUS FAN DRIVE...................58
RADIATOR - 3.9L/5.2L/5.9L
DESCRIPTION...........................59
OPERATION.............................59
DIAGNOSIS AND TESTING.................59
RADIATOR COOLANT FLOW..............59
REMOVAL..............................59
CLEANING..............................60
INSPECTION............................61
INSTALLATION...........................61
RADIATOR - 8.0L
DESCRIPTION...........................61
OPERATION.............................61
DIAGNOSIS AND TESTING.................61
RADIATOR COOLANT FLOW..............61
REMOVAL..............................62
CLEANING..............................62
INSPECTION............................62
INSTALLATION...........................63
RADIATOR - 5.9L DIESEL
DESCRIPTION...........................63
OPERATION.............................63
BR/BEENGINE 7 - 39

(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)

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
7 - 46 ENGINEBR/BE
ENGINE BLOCK HEATER - 3.9L/5.2L/5.9L (Continued)

(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.
ENGINE BLOCK HEATER - 5.9L
DIESEL
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 diesel engine has the block heater located
on the right side of the engine below the exhaust
manifold next to the oil cooler (Fig. 12).
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 the battery negative cables.
(2) Drain coolant from radiator and cylinder block
(Refer to 7 - COOLING - STANDARD PROCE-
DURE).
(3) Unscrew the power cord retaining cap and dis-
connect cord from heater element.
(4) Using a suitable size socket, loosen and remove
the block heater element (Fig. 13).
INSTALLATION
(1) Clean and inspect the threads in the cylinder
block.
(2) Coat heater element threads with Mopart
Thread Sealer with Teflon.
(3) Screw block heater into cylinder block and
tighten to 43 N´m (32 ft. lbs.).
(4) Connect block heater cord and tighten retain-
ing cap.
(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. 11 Block HeaterÐ8.0L V-10 Engine
1 - FREEZE PLUG HOLE
2 - SCREW
3 - POWER CORD (120V AC)
4 - BLOCK HEATER
5 - HEATING COIL
Fig. 12 Engine Block HeaterÐ5.9L Diesel Engine
1 - BLOCK HEATER
BR/BEENGINE 7 - 47
ENGINE BLOCK HEATER - 8.0L (Continued)

ENGINE COOLANT TEMP
SENSOR - 3.9L/5.2L/5.9L
DESCRIPTION
The Engine Coolant Temperature (ECT) sensor is
used to sense engine coolant temperature. The sensor
protrudes into an engine water jacket.
The ECT sensor is a two-wire Negative Thermal
Coefficient (NTC) sensor. Meaning, as engine coolant
temperature increases, resistance (voltage) in the
sensor decreases. As temperature decreases, resis-
tance (voltage) in the sensor increases.
OPERATION
At key-on, the Powertrain Control Module (PCM)
sends out a regulated 5 volt signal to the ECT sensor.
The PCM then monitors the signal as it passes
through the ECT sensor to the sensor ground (sensor
return).
When the engine is cold, the PCM will operate in
Open Loop cycle. It will demand slightly richer air-
fuel mixtures and higher idle speeds. This is done
until normal operating temperatures are reached.
The PCM uses inputs from the ECT sensor for the
following calculations:
²for engine coolant temperature gauge operation
through CCD or PCI (J1850) communications
²Injector pulse-width
²Spark-advance curves
²ASD relay shut-down times
²Idle Air Control (IAC) motor key-on steps
²Pulse-width prime-shot during cranking
²O2 sensor closed loop times
²Purge solenoid on/off times
²EGR solenoid on/off times (if equipped)
²Leak Detection Pump operation (if equipped)²Radiator fan relay on/off times (if equipped)
²Target idle speed
REMOVAL
WARNING: HOT, PRESSURIZED COOLANT CAN
CAUSE INJURY BY SCALDING. COOLING SYSTEM
MUST BE PARTIALLY DRAINED BEFORE REMOV-
ING THE COOLANT TEMPERATURE SENSOR.
REFER TO GROUP 7, COOLING.
(1) Partially drain cooling system (Refer to 7 -
COOLING - STANDARD PROCEDURE).
(2) Remove air cleaner assembly.
(3) Disconnect electrical connector from sensor
(Fig. 14).
(4)Engines with air conditioning:When
removing the connector from sensor, do not pull
directly on wiring harness. Fabricate an L-shaped
hook tool from a coat hanger (approximately eight
inches long). Place the hook part of tool under the
connector for removal. The connector is snapped onto
the sensor. It is not equipped with a lock type tab.
(5) Remove sensor from intake manifold.
INSTALLATION
(1) Install sensor.
(2) Tighten to 6±8 N´m (55±75 in. lbs.) torque.
(3) Connect electrical connector to sensor. The sen-
sor connector is symmetrical (not indexed). It can be
installed to the sensor in either direction.
(4) Install air cleaner assembly.
(5) Refill cooling system (Refer to 7 - COOLING -
STANDARD PROCEDURE).
Fig. 13 Block HeaterÐDiesel Engine
1 - BLOCK HEATER
Fig. 14 Engine Coolant Temperature
1 - GENERATOR
2 - A/C COMPRESSOR
3 - ENGINE COOLANT TEMPERATURE SENSOR
4 - ELEC. CONN.
7 - 48 ENGINEBR/BE
ENGINE BLOCK HEATER - 5.9L DIESEL (Continued)

ENGINE COOLANT
THERMOSTAT - 3.9L/5.2L/5.9L
DESCRIPTION
CAUTION: Do not operate an engine without a ther-
mostat, except for servicing or testing.
The thermostat on the 3.9L, 5.2L and 5.9L gas
powered engines is located beneath the thermostat
housing at the front of the intake manifold (Fig. 15).
The thermostat is a wax pellet driven, reverse pop-
pet choke type.
Coolant leakage into the pellet container will cause
the thermostat to fail in the open position. Thermo-
stats very rarely stick. Do not attempt to free a ther-
mostat with a prying device.
The same thermostat is used for winter and sum-
mer seasons. An engine should not be operated with-
out a thermostat, except for servicing or testing.
Operating without a thermostat causes longer engine
warmup time, unreliable warmup performance,
increased exhaust emissions and crankcase condensa-
tion that can result in sludge formation.
OPERATION
The wax pellet is located in a sealed container at
the spring end of the thermostat. When heated, the
pellet expands, overcoming closing spring tension
and water pump pressure to force the valve to open.
DIAGNOSIS AND TESTINGÐTHERMOSTAT
ON-BOARD DIAGNOSTICS
Allgasoline powered modelsare equipped with
On-Board Diagnostics for certain cooling system com-
ponents. Refer to On-Board Diagnostics (OBD) in the
Diagnosis section of this group for additional infor-
mation. If the powertrain control module (PCM)
detects low engine coolant temperature, it will record
a Diagnostic Trouble Code (DTC) in the PCM mem-
ory. Do not change a thermostat for lack of heat as
indicated by the instrument panel gauge or by poor
heater performance unless a DTC is present. Refer to
the Diagnosis section of this group for other probable
causes. For other DTC numbers, (Refer to 25 - EMIS-
SIONS CONTROL - DESCRIPTION).
The DTC can also be accessed through the DRB
scan tool. Refer to the appropriate Powertrain Diag-
nostic Procedures information for diagnostic informa-
tion and operation of the DRB scan tool.
REMOVAL
WARNING: DO NOT LOOSEN RADIATOR DRAIN-
COCK WITH SYSTEM HOT AND PRESSURIZED.
SERIOUS BURNS FROM COOLANT CAN OCCUR.
Do not waste reusable coolant. If solution is clean,
drain coolant into a clean container for reuse.
If thermostat is being replaced, be sure that
replacement is specified thermostat for vehicle model
and engine type.
Factory installed thermostat housings on 3.9L,
5.2L and 5.9L engines are installed on a gasket with
an anti-stick coating. This will aid in gasket removal
and clean-up.
(1) Disconnect negative battery cable at battery.
(2) Drain cooling system until coolant level is
below thermostat (Refer to 7 - COOLING - STAN-
DARD PROCEDURE).
(3) Air Conditioned vehicles: Remove support
bracket (generator mounting bracket-to-intake mani-
fold) located near rear of generator (Fig. 16).
NOTE: On air conditioning equipped vehicles, the
generator must be partially removed.
Fig. 15 ThermostatÐ5.2L and 5.9L Gas Powered
Engines
1 - THERMOSTAT HOUSING
2 - GASKET
3 - INTAKE MANIFOLD
4 - THERMOSTAT
5 - MACHINED GROOVE
BR/BEENGINE 7 - 49