drain bolt DODGE RAM 2001 Service User Guide

COOLANT RECOVERY
CONTAINER - 8.0L
DESCRIPTION
On the 8.0L V-10 engine the tank is mounted to
right inner fender (Fig. 4), and is made of high tem-
perature plastic.
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 provides
a 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.
RADIATOR FAN - 3.9L/5.2L/
5.9L/8.0L
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 negative battery cable from battery.
(2) Remove throttle cable at top of fan shroud.
(3) All Except 8.0L V-10 Engine: Unsnap coolant
reserve/overflow tank from fan shroud and lay aside.
The tank is held to shroud with T- shaped slots. Do
not disconnect hose or drain coolant from tank.
(4) The thermal viscous fan drive/fan blade assem-
bly is attached (threaded) to water pump hub shaft
(Fig. 6). Remove fan blade/viscous fan drive assembly
from water pump by turning mounting nut counter-
clockwise as viewed from front. Threads on viscous
fan drive areRIGHT-HAND.A Snap-On 36 MM Fan
Wrench (number SP346 from Snap-On Cummins Die-
sel Tool Set number 2017DSP), Special Tool 6958
Spanner Wrench and Adapter Pins 8346 should be
used to prevent pulley from rotating (Fig. 5).
(5) Do not attempt to remove fan/viscous fan drive
assembly from vehicle at this time.
Fig. 3 COOLANT RESERVE/OVERFLOW TANKÐALL
EXCEPT 8.0L V-10 ENGINE
1 - T-SLOTS
2 - ALIGNMENT PIN
3 - FAN SHROUD
4 - COOLANT RESERVE/OVERFLOW TANK
Fig. 4 Coolant Reserve/Overflow TankÐ8.0L V-10
Engine
1 - COOLANT RESERVE/OVERFLOW TANK
2 - TANK MOUNTING BOLTS (3)
3 - ICM MOUNTING BOLTS (2)
4 - IGNITION CONTROL MODULE (ICM)
7 - 42 ENGINEBR/BE
COOLANT RECOVERY CONTAINER - 3.9L/5.2L/5.9L/5.9L DIESEL (Continued)

(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)

(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 COOLANT
THERMOSTAT - 8.0L
DESCRIPTION
CAUTION: Do not operate an engine without a ther-
mostat, except for servicing or testing.
The thermostat on all gas powered engines is
located beneath the thermostat housing at the front
of the intake manifold (Fig. 22).
The thermostat is a moveable sleeve 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 THE RADIATOR
DRAINCOCK WITH THE SYSTEM HOT AND PRES-SURIZED. SERIOUS BURNS FROM THE COOLANT
CAN OCCUR.
Do not waste reusable coolant. If the solution is
clean, drain the coolant into a clean container for
reuse.
If the thermostat is being replaced, be sure that
the replacement is the specified thermostat for the
vehicle model and engine type.
A rubber lip-type seal with a metal shoulder is
pressed into the intake manifold beneath the thermo-
stat (Fig. 23).
(1) Disconnect negative battery cable at battery.
(2) Drain cooling system until coolant level is
below thermostat (Refer to 7 - COOLING - STAN-
DARD PROCEDURE).
Fig. 22 ThermostatÐ8.0L V-10 Engine
1 - COOLANT TEMP. SENSOR (FOR PCM)
2 - HEATER SUPPLY FITTING
3 - BOLTS (6)
4 - HOUSING WITH INTEGRAL SEAL
5 - THERMOSTAT
6 - RUBBER LIP SEAL
7 - TEMP. GAUGE SENDING UNIT
7 - 52 ENGINEBR/BE

to be used with cool or cold temperatures only.
If used with high outside temperatures, serious
engine damage could result.Refer to the litera-
ture supplied with the cover for additional informa-
tion.
(1) To determine if the thermostat is defective, it
must be removed from the vehicle (Refer to 7 -
COOLING/ENGINE/ENGINE COOLANT THERMO-
STAT - REMOVAL).
(2) After the thermostat has been removed, exam-
ine the thermostat and inside of thermostat housing
for contaminants. If contaminants are found, the
thermostat may already be in a ªstuck openº position.
Flush the cooling system before replacing thermostat
(Refer to 7 - COOLING - STANDARD PROCE-
DURE).
(3) Place the thermostat into a container filled
with water.
(4) Place the container on a hot plate or other suit-
able heating device.
(5) Place a commercially available radiator ther-
mometer into the water.
(6) Apply heat to the water while observing the
thermostat and thermometer.
(7) When the water temperature reaches 83ÉC
(181ÉF) the thermostat should start to open (valve
will start to move). If the valve starts to move before
this temperature is reached, it is opening too early.
Replace thermostat. The thermostat should be fully
open (valve will stop moving) at 95ÉC (203ÉF). If the
valve is still moving when the water temperature
reaches 203É, it is opening too late. Replace thermo-
stat. If the valve refuses to move at any time, replace
thermostat.
REMOVAL
WARNING: DO NOT LOOSEN THE RADIATOR
DRAINCOCK WITH THE SYSTEM HOT AND PRES-
SURIZED. SERIOUS BURNS FROM THE COOLANT
CAN OCCUR.
Do not waste reusable coolant. If the solution is
clean, drain the coolant into a clean container for
reuse.
(1) Disconnect the battery negative cables.
(2) Drain cooling system until coolant level is
below thermostat (Refer to 7 - COOLING - STAN-
DARD PROCEDURE).
WARNING: CONSTANT TENSION HOSE CLAMPS
ARE USED ON MOST COOLING SYSTEM HOSES.
WHEN REMOVING OR INSTALLING, USE ONLY
TOOLS DESIGNED FOR SERVICING THIS TYPE OF
CLAMP, SUCH AS SPECIAL CLAMP TOOL (NUMBER
6094). SNAP-ON CLAMP TOOL (NUMBER HPC-20)
MAY BE USED FOR LARGER CLAMPS. ALWAYSWEAR SAFETY GLASSES WHEN SERVICING CON-
STANT TENSION CLAMPS.
CAUTION: A number or letter is stamped into the
tongue of constant tension clamps. If replacement
is necessary, use only an original equipment clamp
with a matching number or letter.
(3) Remove radiator hose clamp and hose from
thermostat housing.
(4) Remove the three (3) water outlet-to-cylinder
head bolts and remove the water outlet connector
(Fig. 27).
(5) Clean the mating surfaces of the water outlet
connector and clean the thermostat seat groove at
the top of the thermostat housing (Fig. 27).
INSTALLATION
(1) Install the thermostat into the groove in the
top of the thermostat housing (Fig. 27).
(2) Install the water outlet connector and bolts.
Tighten the bolts to 24 N´m (18 ft. lbs.) torque.
(3) Install the radiator upper hose and clamp.
(4) Fill the cooling system with coolant (Refer to 7
- COOLING - STANDARD PROCEDURE).
(5) Connect the battery negative cables.
(6) Start the engine and check for coolant leaks.
Run engine to check for proper thermostat operation.
Fig. 27 Thermostat Removal/Installation
1 - WATER OUTLET CONNECTOR
2 - THERMOSTAT HOUSING
3 - THERMOSTAT
BR/BEENGINE 7 - 55
ENGINE COOLANT THERMOSTAT - 5.9L DIESEL (Continued)

and compressed air to the back (engine side) of the
radiator to flush the radiator and/or A/C condenser of
debris.
INSPECTION
Inspect the radiator side tanks for cracks, broken
or missing fittings also inspect the joint where the
tanks seam up to the radiator core for signs of leak-
age and/or deteriorating seals.
Inspect radiator core for corroded, bent or missing
cooling fins. Inspect the core for bent or damaged
cooling tubes.
INSTALLATION
(1) Position fan shroud over the fan blades rear-
ward towards engine.
(2) Install rubber insulators to alignment dowels
at lower part of radiator.
(3) Lower the radiator into position while guiding
the two alignment dowels into lower radiator sup-
port. Different alignment holes are provided in the
lower radiator support for each engine application.
(4) Install two upper radiator mounting bolts.
Tighten bolts to 11 N´m (95 in. lbs.) torque.
(5) Position the rubber shields to the sides of radi-
ator. Install the plastic clips retaining the rubber
shields to the sides of radiator.
(6) Connect both radiator hoses and install hose
clamps.
(7) Install windshield washer reservoir tank.
(8) Position fan shroud to flanges on sides of radi-
ator. Install fan shroud mounting bolts (Fig. 34).
Tighten bolts to 6 N´m (50 in. lbs.) torque.
(9) Install coolant reserve/overflow tank hose to
radiator filler neck nipple.
(10) Install coolant reserve/overflow tank to fan
shroud (fits into T-slots on shroud).
(11) Install battery negative cables.
(12) Position heater controls tofull heatposition.
(13) Fill cooling system with coolant (Refer to 7 -
COOLING - STANDARD PROCEDURE).
(14) Operate engine until it reaches normal tem-
perature. Check cooling system fluid levels.
RADIATOR - 8.0L
DESCRIPTION
The radiator is a aluminum cross-flow design with
horizontal tubes through the radiator core and verti-
cal plastic side tanks (Fig. 36).
This radiator contains an internal transmission oil
cooler only on the V-10 gas engine and the 5.9L die-
sel engine combinations.
OPERATION
The radiator supplies sufficient heat transfer using
the cooling fins interlaced between the horizontal
tubes in the radiator core to cool the engine.
DIAGNOSIS AND TESTINGÐRADIATOR
COOLANT FLOW
Use the following procedure to determine if coolant
is flowing through the cooling system.
(1) Idle engine until operating temperature is
reached. If the upper radiator hose is warm to the
touch, the thermostat is opening and coolant is flow-
ing to the radiator.
WARNING: HOT, PRESSURIZED COOLANT CAN
CAUSE INJURY BY SCALDING. USING A RAG TO
COVER THE RADIATOR PRESSURE CAP, OPEN
RADIATOR CAP SLOWLY TO THE FIRST STOP. THIS
WILL ALLOW ANY BUILT-UP PRESSURE TO VENT
TO THE RESERVE/OVERFLOW TANK. AFTER PRES-
SURE BUILD-UP HAS BEEN RELEASED, REMOVE
CAP FROM FILLER NECK.
(2) Drain a small amount of coolant from the radi-
ator until the ends of the radiator tubes are visible
through the filler neck. Idle the engine at normal
operating temperature. If coolant is flowing past the
exposed tubes, the coolant is circulating.
Fig. 36 Cross Flow RadiatorÐTypical
1 - COOLING TUBES
2 - TANKS
BR/BEENGINE 7 - 61
RADIATOR - 3.9L/5.2L/5.9L (Continued)

REMOVAL
(1) Disconnect battery negative cables.
WARNING: DO NOT REMOVE THE CYLINDER
BLOCK DRAIN PLUGS OR LOOSEN THE RADIATOR
DRAINCOCK WITH THE SYSTEM HOT AND UNDER
PRESSURE. SERIOUS BURNS FROM COOLANT
CAN OCCUR.
(2) Drain the cooling system (Refer to 7 - COOL-
ING - STANDARD PROCEDURE).
WARNING: CONSTANT TENSION HOSE CLAMPS
ARE USED ON MOST COOLING SYSTEM HOSES.
WHEN REMOVING OR INSTALLING, USE ONLY
TOOLS DESIGNED FOR SERVICING THIS TYPE OF
CLAMP, SUCH AS SPECIAL CLAMP TOOL (NUMBER
6094). SNAP-ON CLAMP TOOL (NUMBER HPC-20)
MAY BE USED FOR LARGER CLAMPS. ALWAYS
WEAR SAFETY GLASSES WHEN SERVICING CON-
STANT TENSION CLAMPS.
CAUTION: A number or letter is stamped into the
tongue of constant tension clamps. If replacement
is necessary, use only an original equipment clamp
with a matching number or letter.
(3) Remove hose clamps and hoses from radiator.
(4) Remove coolant reserve/overflow tank hose
from radiator filler neck nipple.
(5) The coolant recovery/reservoir does not require
removal. Disconnect the overflow hose from the radi-
ator.
(6) Disconnect electrical connectors at windshield
washer reservoir tank and remove tank.
(7) Remove the four fan shroud mounting bolts
(Fig. 37). Position shroud rearward over the fan
blades towards engine.
(8) Remove the two radiator upper mounting bolts
(Fig. 38).
(9) Lift radiator straight up and out of engine com-
partment. The bottom of the radiator is equipped
with two alignment dowels that fit into holes in the
lower radiator support panel (Fig. 38). Rubber bis-
cuits (insulators) are installed to these dowels. Take
care not to damage cooling fins or tubes on the radi-
ator and air conditioning condenser when removing.
CLEANING
Clean radiator fins are necessary for good heat
transfer. The radiator and air conditioning fins
should be cleaned when an accumulation of debris
has occurred. With the engine cold, apply cold water
and compressed air to the back (engine side) of the
radiator to flush the radiator and/or A/C condenser of
debris.
INSPECTION
Inspect the radiator side tanks for cracks, broken
or missing fittings also inspect the joint where the
tanks seam up to the radiator core for signs of leak-
age and/or deteriorating seals.
Fig. 37 Fan Shroud MountingÐ8.0L Engine
1 - RADIATOR SUPPORT
2 - RADIATOR
3 - BOLTS (4)
4 - FAN SHROUD
Fig. 38 Typical Radiator Mounting
1 - MOUNTING BOLTS
2 - RADIATOR
3 - ALIGNMENT DOWELS (2)
4 - RADIATOR SUPPORT
7 - 62 ENGINEBR/BE
RADIATOR - 8.0L (Continued)

Inspect radiator core for corroded, bent or missing
cooling fins. Inspect the core for bent or damaged
cooling tubes.
INSTALLATION
(1) Position fan shroud over the fan blades rear-
ward towards engine.
(2) Install rubber insulators to alignment dowels
at lower part of radiator.
(3) Lower the radiator into position while guiding
the two alignment dowels into lower radiator sup-
port. Different alignment holes are provided in the
lower radiator support for each engine application.
(4) Install two upper radiator mounting bolts.
Tighten bolts to 11 N´m (95 in. lbs.) torque.
(5) Connect both radiator hoses and install hose
clamps.
(6) Install windshield washer reservoir tank.
(7) Position fan shroud to flanges on sides of radi-
ator. Install fan shroud mounting bolts (Fig. 37).
Tighten bolts to 6 N´m (50 in. lbs.) torque.
(8) Install coolant reserve/overflow tank hose to
radiator filler neck nipple.
(9) Connect the overflow hose to the radiator.
(10) Install battery negative cables.
(11) Position heater controls tofull heatposition.
(12) Fill cooling system with coolant (Refer to 7 -
COOLING - STANDARD PROCEDURE).
(13) Operate engine until it reaches normal tem-
perature. Check cooling system fluid levels.
RADIATOR - 5.9L DIESEL
DESCRIPTION
The radiator is a aluminum cross-flow design with
horizontal tubes through the radiator core and verti-
cal plastic side tanks (Fig. 39).
This radiator contains an internal transmission oil
cooler only on the V-10 gas engine and the 5.9L die-
sel engine combinations.
OPERATION
The radiator supplies sufficient heat transfer using
the cooling fins interlaced between the horizontal
tubes in the radiator core to cool the engine.
DIAGNOSIS AND TESTINGÐRADIATOR
COOLANT FLOW
Use the following procedure to determine if coolant
is flowing through the cooling system.
(1) Idle engine until operating temperature is
reached. If the upper radiator hose is warm to the
touch, the thermostat is opening and coolant is flow-
ing to the radiator.WARNING: HOT, PRESSURIZED COOLANT CAN
CAUSE INJURY BY SCALDING. USING A RAG TO
COVER THE RADIATOR PRESSURE CAP, OPEN
RADIATOR CAP SLOWLY TO THE FIRST STOP. THIS
WILL ALLOW ANY BUILT-UP PRESSURE TO VENT
TO THE RESERVE/OVERFLOW TANK. AFTER PRES-
SURE BUILD-UP HAS BEEN RELEASED, REMOVE
CAP FROM FILLER NECK.
(2) Drain a small amount of coolant from the radi-
ator until the ends of the radiator tubes are visible
through the filler neck. Idle the engine at normal
operating temperature. If coolant is flowing past the
exposed tubes, the coolant is circulating.
REMOVAL
(1) Disconnect both battery negative cables.
Remove the nuts retaining the positive cable to the
top of radiator. Position positive battery cable to rear
of vehicle.
WARNING: DO NOT REMOVE THE CYLINDER
BLOCK DRAIN PLUGS OR LOOSEN THE RADIATOR
DRAINCOCK WITH THE SYSTEM HOT AND UNDER
PRESSURE. SERIOUS BURNS FROM COOLANT
CAN OCCUR.
(2) Drain the cooling system (Refer to 7 - COOL-
ING - STANDARD PROCEDURE).
Fig. 39 Cross Flow RadiatorÐTypical
1 - COOLING TUBES
2 - TANKS
BR/BEENGINE 7 - 63
RADIATOR - 8.0L (Continued)

ket has swollen and prevents vent valve from open-
ing, replace cap.
Hold cap at eye level, upside down. If any light can
be seen between vent valve and rubber gasket,
replace cap.Do not use a replacement cap that
has a spring to hold vent shut.A replacement cap
must be the type designed for a coolant reserve/over-
flow system with a completely sealed diaphragm
spring and a rubber gasket. This gasket is used to
seal to radiator filler neck top surface. Use of proper
cap will allow coolant return to radiator.
WATER PUMP - 3.9L/5.2L/5.9L
DESCRIPTION
The water pump is located on the engine front
cover, and has an integral pulley attached (Fig. 46).
The water pump impeller is pressed onto the rear
of a shaft that rotates in a bearing pressed into the
water pump body. The body has a small hole for ven-
tilation. The water pump seals are lubricated by
antifreeze in the coolant mixture. Additional lubrica-
tion is not necessary.
OPERATION
A centrifugal water pump circulates coolant
through the water jackets, passages, intake manifold,
radiator core, cooling system hoses and heater core,
this coolant absorbs the heat generated when the
engine is running. The pump is driven by the engine
crankshaft via a drive belt.
DIAGNOSIS AND TESTINGÐWATER PUMP
A quick test to determine if pump is working is to
check if heater warms properly. A defective water
pump will not be able to circulate heated coolant
through the long heater hose to the heater core.
REMOVAL
The water pump on all models can be removed
without discharging the air conditioning system (if
equipped).
The water pump on all gas powered engines is
bolted directly to the engine timing chain case/cover.
On all 3.9L/5.2L/5.9L gas powered engines, a gas-
ket is used as a seal between the water pump and
timing chain case/cover.
If water pump is replaced because of bearing/shaft
damage or leaking shaft seal, the mechanical cooling
fan assembly should also be inspected. Inspect for
fatigue cracks, loose blades or loose rivets that could
have resulted from excessive vibration. Replace fan if
any of these conditions are found. Also check condi-
tion of the thermal viscous fan drive (Refer to 7 -
COOLING/ENGINE/FAN DRIVE VISCOUS
CLUTCH - DIAGNOSIS AND TESTING).
(1) Disconnect negative cable from battery.
(2) Drain cooling system (Refer to 7 - COOLING -
STANDARD PROCEDURE).
Do not waste reusable coolant. If solution is clean,
drain coolant into a clean container for reuse.
(3) Remove windshield washer reservoir tank from
radiator fan shroud.
Fig. 45 Radiator Pressure Cap
1 - STAINLESS-STEEL SWIVEL TOP
2 - RUBBER SEALS
3 - VENT VALVE
4 - RADIATOR TANK
5 - FILLER NECK
6 - OVERFLOW NIPPLE
7 - MAIN SPRING
8 - GASKET RETAINER
Fig. 46 Water Pump LocationÐTypical
1 - WATER PUMP BYPASS HOSE
2 - FAN BLADE ASSEMBLY
3 - VISCOUS FAN DRIVE
4 - WATER PUMP AND PULLEY
BR/BEENGINE 7 - 67
RADIATOR PRESSURE CAP (Continued)

(4) Disconnect the coolant reserve/overflow tank-
to-radiator hose at the tank.
(5) Remove the four fan shroud mounting bolts at
the radiator (Fig. 47). Do not attempt to remove
shroud from vehicle at this time.
WARNING: CONSTANT TENSION HOSE CLAMPS
ARE USED ON MOST COOLING SYSTEM HOSES.
WHEN REMOVING OR INSTALLING, USE ONLY
TOOLS DESIGNED FOR SERVICING THIS TYPE OF
CLAMP, SUCH AS SPECIAL CLAMP TOOL (NUMBER
6094). SNAP-ON CLAMP TOOL (NUMBER HPC-20)
MAY BE USED FOR LARGER CLAMPS. ALWAYS
WEAR SAFETY GLASSES WHEN SERVICING CON-
STANT TENSION CLAMPS.
CAUTION: A number or letter is stamped into the
tongue of constant tension clamps . If replacement
is necessary, use only an original equipment clamp
with a matching number or letter.
(6) Remove upper radiator hose at radiator.
(7) The thermal viscous fan drive is attached
(threaded) to the water pump hub shaft (Fig. 49).
Remove the fan/fan drive assembly from water pump
by turning the mounting nut counterclockwise (as
viewed from front). Threads on the fan drive are
RIGHT-HAND.A Snap-On 36 MM Fan Wrench
(number SP346 from Snap-On Cummins Diesel Tool
Set number 2017DSP) can be used with Special Tool
6958 Spanner Wrench and Adapter Pins 8346 (Fig.
48) to prevent the pulley from rotating.(8) If water pump is being replaced, do not unbolt
fan blade assembly (Fig. 49) from the thermal control
fan drive.
(9) Remove fan blade/fan drive and fan shroud as
an assembly from vehicle.
(10) After removing fan blade/fan drive assembly,
do notplace the thermal viscous fan drive in the
horizontal position. If stored horizontally, the silicone
fluid in the viscous drive could drain into its bearing
assembly and contaminate the bearing lubricant.
(11) Remove accessory drive belt (Refer to 7 -
COOLING/ACCESSORY DRIVE/DRIVE BELTS -
REMOVAL) (Fig. 50).
(12) Remove the lower radiator hose and heater
hose from water pump.
(13) Loosen heater hose coolant return tube
mounting bolt (Fig. 51) and remove tube from water
pump. Discard the old tube O-ring.
(14) Remove the seven water pump mounting bolts
(Fig. 52).
(15) Loosen the clamp at the water pump end of
bypass hose (Fig. 49). Slip the bypass hose from the
water pump while removing pump from vehicle. Do
not remove the clamp from the bypass hose.
(16) Discard old gasket.
CAUTION: Do not pry the water pump at timing
chain case/cover. The machined surfaces may be
damaged resulting in leaks.
Fig. 47 Typical Fan Shroud Mounting
1 - RADIATOR SUPPORT
2 - RADIATOR
3 - BOLTS (4)
4 - FAN SHROUDFig. 48 Using Special Tool 6958 Spanner Wrench
and Adapter Pins 8346
1 - SPECIAL TOOL 6958 SPANNER WRENCH WITH ADAPTER
PINS 8346
2-FAN
7 - 68 ENGINEBR/BE
WATER PUMP - 3.9L/5.2L/5.9L (Continued)