2003 DODGE RAM radiator drain

NOTE: The radiator is equipped with one alignment
dowel on the bottom of the outlet tank and one
retaining bracket on the front side of the inlet tank.
Both features have rubber insulators attached to
them that must be present. The alignment dowel fits
into a hole at the bottom of the front end sheet
metal vertical support post and the support bracket
rests on top of the lower radiator closure tube.
CLEANING
Clean radiator fins are necessary for good heat
transfer. The radiator and oil cooler 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 radi-
ator to flush the radiator and/or oil coolers 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 the fan shroud over the fan blades
rearward towards engine.
(2) Install the rubber insulators to the lower radi-
ator mounting features (alignment dowel and support
bracket at the lower part of the radiator).
(3) Lower the radiator into position while guiding
the alignment dowel into the vertical post bracket.
Position and seat the lower radiator support bracket
onto the lower radiator closure tube.
(4) Install the upper radiator mounting bolts.
Tighten bolts to 8.5 N´m (75 in. lbs.).
(5) Connect the lower radiator hose and install the
clamp in the proper position.
(6) Connect the power steering hoses to the power
steering oil cooler and install the clamps.
(7) Connect the transmission oil cooler lines to the
transmission oil cooler and install the secondary
latches.
(8) Position the fan shroud into the mounting clips
on the radiator tanks and secure with bolts. Tighten
the bolts to 8.5 N´m (75 in. lbs.).
(9) Secure the power steering hoses into the clip
on the lower fan shroud.
(10) Install the windshield washer reservoir tank
and connect the hose and electrical connector.
(11) Install coolant reserve/overflow container
hose(s) to radiator filler neck and secure properly
with clamps.
Fig. 33 Fan Shroud
1 - RADIATOR
2 - SCREWS
3 - FAN SHROUD
4 - SLIDE MOUNT
Fig. 34 Radiator
1 - SCREW
2 - SCREW
3 - LOWER MOUNT
4 - RADIATOR
5 - DRAINCOCK
6 -LOWER MOUNT
7 - 58 ENGINEDR
RADIATOR (Continued)

(12) Install coolant reserve/overflow container or
degas container to fan shroud and tighten the bolts
to 8.5 N´m (75 in. lbs.).
(13) Connect upper radiator hose and install
clamp.
(14) Install battery negative cable.
(15) Fill cooling system with coolant (Refer to 7 -
COOLING - STANDARD PROCEDURE).
(16) Operate the engine until it reaches normal
operating temperature. 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. 35).
This radiator does not contain an internal trans-
mission oil cooler
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.
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 air box and turbocharger inlet tube.
(4) Remove coolant tank hose, washer bottle hose
and the positive battery cable from the fastening
clips located on top of the radiator.
(5) Remove hose clamps and hoses from radiator.
Fig. 35 Radiator Ð Typical
1 - SCREW
2 - SCREW
3 - LOWER MOUNT
4 - RADIATOR
5 - DRAINCOCK
6 -LOWER MOUNT
DRENGINE 7 - 59
RADIATOR (Continued)

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 the 5.9L gas powered engine, a gasket 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 the negative cable.
(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 the radiator fan (Refer to 7 - COOL-
ING/ENGINE/RADIATOR FAN - REMOVAL)
(4) Remove accessory drive belt (Refer to 7 -
COOLING/ACCESSORY DRIVE/DRIVE BELTS -
REMOVAL) (Fig. 41).
(5) Remove the lower radiator hose and heater
hose from the water pump.
(6) Loosen the heater hose coolant return tube
mounting bolt (Fig. 42) and remove the tube from the
water pump. Discard the old tube O-ring.
(7) Remove the water pump mounting bolts (Fig.
43).(8) Loosen the clamp at the water pump end of
bypass hose (Fig. 42). Slip the bypass hose from the
Fig. 40 Water Pump Location Ð Typical
1 - WATER PUMP BYPASS HOSE
2 - FAN BLADE ASSEMBLY
3 - VISCOUS FAN DRIVE
4 - WATER PUMP AND PULLEY
Fig. 41 Belt Tensioner 5.9L V-8 Engine
1 - IDLER PULLEY
2 - TENSIONER
3 - FAN BLADE
Fig. 42 Coolant Return Tube 5.9L
1 - COOLANT RETURN TUBE
2 - WATER PUMP
3 - TUBE MOUNTING BOLT
4 - O-RING
DRENGINE 7 - 63
WATER PUMP - 5.9L (Continued)

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.
OPERATIONÐWATER PUMP BYPASS
When the thermostat is in the closed position the
bypass gallery is not obstructed allowing 100% flow.
When the thermostat is in the open position the stub
shaft enters the bypass gallery obstructing bypass
coolant flow by 50%. This design allows the coolant
to reach operating temperature quickly when cold,
while adding extra cooling during normal tempera-
ture operation.
REMOVAL
The water pump on 3.7L/4.7L engines is bolted
directly to the engine timing chain case cover.
(1) Disconnect the negative battery cable.
(2) Drain cooling system (Refer to 7 - COOLING -
STANDARD PROCEDURE).
(3) Remove fan/viscous fan drive assembly from
water pump (Fig. 46) (Refer to 7 - COOLING/EN-
GINE/FAN DRIVE VISCOUS CLUTCH - REMOV-
AL). Do not attempt to remove fan/viscous fan drive
assembly 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. ALWAYS WEAR SAFETY GLASSES WHEN
SERVICING CONSTANT 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 matching number or letter and width.
(4) If the water pump is being replaced, do not
unbolt the fan blade assembly from the thermal vis-
cous fan drive.
(5) Remove the radiator fan (Refer to 7 - COOL-
ING/ENGINE/RADIATOR FAN - REMOVAL).
(6) Remove accessory drive belt (Fig. 47) (Refer to
7 - COOLING/ACCESSORY DRIVE/DRIVE BELTS -
REMOVAL).
(7) Remove the lower radiator hose clamp and
remove the lower hose at the water pump.
(8) Remove the water pump mounting bolts.
Fig. 44 Water Pump and Timing Chain Cover
1 - INTEGRAL WATER PUMP PULLEY
2 - TIMING CHAIN COVER
3 - THERMOSTAT HOUSING
4 - HEATER HOSE FITTINGS
5 - WATER PUMP
Fig. 45 Water/Coolant Bypass Flow and Thermostat
1 - FROM HEATER AND DEGAS CONTAINER
2 - FROM RADIATOR
3 - TO WATER PUMP
4 - ENGINE BYPASS
5 - THERMOSTAT
DRENGINE 7 - 65
WATER PUMP - 3.7L/4.7L (Continued)

CAUTION: When installing the serpentine accessory
drive belt, the belt must be routed correctly. If not,
the engine may overheat due to the water pump
rotating in the wrong direction. Refer to (Fig. 49) for
the correct belt routing. Or, refer to the Belt Routing
Label located in the engine compartment. The cor-
rect belt with correct length must be used.
(6) Install the radiator fan (Refer to 7 - COOLING/
ENGINE/RADIATOR FAN - INSTALLATION).
(7) Fill cooling system (Refer to 7 - COOLING -
STANDARD PROCEDURE).
(8) Connect the negative battery cable.
(9) Start and warm the engine. Check for leaks.
WATER PUMP - 5.9L DIESEL
DESCRIPTION
The water pump is mounted to the front of the
engine block between the automatic belt tensioner
and the fan drive pulley.
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 byantifreeze in the coolant mixture. Additional lubrica-
tion is not necessary.
OPERATION
The diesel engine water pump draws coolant from
radiator outlet and circulates it through engine,
heater core and back to radiator inlet. The crank-
shaft pulley drives the water pump with a serpentine
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
(1) Disconnect battery negative cables.
(2) Drain cooling system (Refer to 7 - COOLING -
STANDARD PROCEDURE).
(3) Remove the accessory drive belt (Refer to 7 -
COOLING/ACCESSORY DRIVE/DRIVE BELTS -
REMOVAL).
(4) Remove water pump mounting bolts (Fig. 50).
(5) Clean water pump sealing surface on cylinder
block.
CLEANING
Clean gasket mating surfaces as necessary.
Fig. 49 Belt Routing 3.7L
1 - GENERATOR PULLEY
2 - ACCESSORY DRIVE BELT
3 - POWER STEERING PUMP PULLEY
4 - CRANKSHAFT PULLEY
5 - IDLER PULLEY
6 - TENSIONER
7 - A/C COMPRESSOR PULLEY
8 - WATER PUMP PULLEY
Fig. 50 Water Pump Removal/Installation
1 - O-RING SEAL (SQUARE)
2 - WATER PUMP
3 - BOLT (2)
DRENGINE 7 - 67
WATER PUMP - 3.7L/4.7L (Continued)

INSPECTION
Visually inspect the water pump and replace if it
has any of the following conditions:
²The body is cracked or damaged
²Water leaks from the shaft seal. This is evident
by traces of coolant below the vent hole
²Loose or rough turning bearing.
²Impeller rubbing the pump body
INSTALLATION
(1) Install new O-ring seal in groove on water
pump (Fig. 51).
(2) Install water pump. Tighten mounting bolts to
24 N´m (18 ft. lbs.) torque.
(3) Install accessory drive belt. Refer to procedure
in this group.
(4) Install the bolt retaining the wiring harness
near top of water pump.
(5) Fill cooling system. Refer to Refilling Cooling
System in this section.
(6) Connect both battery cables.
(7) Start and warm the engine. Check for leaks.
WATER PUMP INLET TUBE -
5.9L
REMOVAL
REMOVAL - WATER PUMP BYPASS HOSE
WITH AIR CONDITIONING
If equipped with A/C, the generator and A/C com-
pressor along with their common mounting bracket
(Fig. 52) must be partially removed. Removing thegenerator or A/C compressor from their mounting
bracket is not necessary. Also, discharging the A/C
system is not necessary.Do notremove any refriger-
ant lines from A/C compressor.
WARNING: THE A/C SYSTEM IS UNDER PRESSURE
EVEN WITH THE ENGINE OFF. REFER TO REFRIG-
ERANT WARNINGS IN SECTION 24 - HEATING AND
AIR CONDITIONING.
(1) Disconnect the negative battery cable.
(2) Partially drain the cooling system (Refer to 7 -
COOLING - STANDARD PROCEDURE).Do not
waste reusable coolant. If the solution is clean, drain
the coolant into a clean container for reuse.
(3) Remove the upper radiator hose clamp at the
radiator. A special clamp tool must be used to remove
the constant tension clamps. Removethe hose at the
radiator.
(4) Unplug the wiring harness from the A/C com-
pressor.
(5) Remove the air cleaner assembly.
(6) Remove the accessory drive belt (Refer to 7 -
COOLING/ACCESSORY DRIVE/DRIVE BELTS -
REMOVAL).
(7) The drive belt idler pulley must be removed to
gain access to one of the A/C compressor/generator
bracket mounting bolts. Remove the idler pulley bolt
and remove idler pulley (Fig. 53).
(8) Remove the engine oil dipstick tube mounting
bolt at the side of the A/C-generator mounting
bracket.
(9) Disconnect the throttle body control cables.
Fig. 51 Pump O-ring Seal
1 - O-RING SEAL
2 - GROOVE
3 - WATER PUMP
Fig. 52 Generator - A/C Compressor Mounting
Bracket - Typical
7 - 68 ENGINEDR
WATER PUMP - 5.9L DIESEL (Continued)

CAUTION: A number or letter is stamped into the
tongue of the constant tension clamps. If replace-
ment is necessary, use only an original equipment
clamp with a matching number or letter and width.
(2) Loosen both of the bypass hose clamps and
position them to the center of the hose.
(3) Removethe hose from the vehicle.
INSTALLATION
INSTALLATION - WATER PUMP BYPASS HOSE
WITH AIR CONDITIONING
(1) Position the bypass hose clamps to the center
of the bypass hose.
(2) Install the bypass hose to the engine.
(3) Secure both of the hose clamps.
(4) Install the generator-A/C mounting bracket
assembly to the engine. Tighten bolt number 1 (Fig.
53) to 41 N´m (30 ft. lbs.). Tighten bolt number 2
(Fig. 53) to 28 N´m (20 ft. lbs.). Tighten bracket
mounting bolts (Fig. 53) (Fig. 53) to 40 N´m (30 ft.
lbs.).
(5) Install a new O-ring to the heater hose coolant
return tube. Coat the new O-ring with antifreeze
before installation.
(6) Install the coolant return tube and its mount-
ing bolt to the engine.
(7) Connect the throttle body control cables.
(8) Install the oil dipstick mounting bolt.
(9) Install the idler pulley. Tighten the bolt to 41
N´m (30 ft. lbs.) (Fig. 57).
(10) Install the drive belt (Refer to 7 - COOLING/
ACCESSORY DRIVE/DRIVE BELTS - INSTALLA-
TION).CAUTION: When installing the serpentine accessory
drive belt, the belt must be routed correctly. If not,
the engine may overheat due to the water pump
rotating in the wrong direction (Refer to 7 - COOL-
ING/ACCESSORY DRIVE/DRIVE BELTS - INSTALLA-
TION). The correct belt with the correct length must
be used.
(11) Install the air cleaner assembly.
(12) Install the upper radiator hose to the radiator.
(13) Connect the throttle cable to the clip at the
radiator fan shroud.
(14) Connect the wiring harness to the A/C com-
pressor.
(15) Fill the cooling system (Refer to 7 - COOLING
- STANDARD PROCEDURE).
(16) Start and warm the engine. Check for leaks.
INSTALLATION - WATER PUMP BYPASS HOSE
WITHOUT AIR CONDITIONING
(1) Position the bypass hose clamps to the center
of the bypass hose.
(2) Install the bypass hose tothe engine.
(3) Secure both of the hose clamps.
(4) Fill the cooling system (Refer to 7 - COOLING
- STANDARD PROCEDURE).
(5) Start and warm the engine. Check for leaks.
WATER PUMP - 5.7L
REMOVAL
(1) Disconnect negative battery cable.
(2) Drain coolant.
(3) Remove serpentine belt.
(4) Remove fan clutch assembly.
(5) Remove coolant fill bottle.
Fig. 56 Water Pump Bypass Hose - Typical
1 - WATER PUMP BYPASS HOSE
2 - FAN BLADE ASSEMBLY
3 - VISCOUS FAN DRIVE
4 - WATER PUMP AND PULLEY
Fig. 57 Tensioner Mounting
1 - DOWEL PIN HOLE
2 - TENSIONER MOUNTING BRACKET
7 - 70 ENGINEDR
WATER PUMP INLET TUBE - 5.9L (Continued)

TRANSMISSION
TABLE OF CONTENTS
page page
TRANS COOLER
DESCRIPTION
DESCRIPTION........................72
DESCRIPTION........................72
OPERATION...........................72
REMOVAL.............................72
DISASSEMBLY - 5.9L ONLY...............73
ASSEMBLY - 5.9L ONLY..................73
INSTALLATION.........................73TRANS COOLER - 5.9L DIESEL
DESCRIPTION.........................73
OPERATION...........................74
REMOVAL
REMOVALÐAIR TO OIL COOLER.........74
REMOVALÐWATER TO OIL COOLER......74
INSTALLATION
INSTALLATIONÐAIR TO OIL COOLER.....75
INSTALLATION.......................75
TRANS COOLER
DESCRIPTION
DESCRIPTION
An air-to-oil transmission oil cooler is standard on
all engine packages. The transmission oil cooler is
mounted to the front of the radiator above the power
steering cooler (Fig. 1).
DESCRIPTION
An air-to-oil transmission oil cooler is standard on
all engine packages. The transmission oil cooler is
mounted to the front of the radiator above the power
steering cooler (Fig. 2).
OPERATION
Transmission oil is routed through the cooler
where heat is removed from the transmission oil
before returning to the transmission. Vehicles
equipped with the 5.9L engine have an internal ther-
mostat that controls fluid flow through the cooler-
.When the transmission fluid is cold ( less than
operating temperature) the fluid is routed through
the cooler bypass. when the transmission fluid
reaches operating temperatures and above, the ther-
mostat closes off the bypass allowing fluid flow
through the cooler. The thermostat is serviceable.
NOTE: Vehicles with the 3.7L/4.7L engines are not
equipped with the oil cooler thermostat.
REMOVAL
(1) Disconnect the battery negative cable.
(2) Place a drain pan under the oil cooler lines.(3) Disconnect the transmission oil cooler line
quick-connect fitting at the cooler outlet using the
quick connect release tool 6935. Plug the cooler lines
to prevent oil leakage.
(4) Unsnap the transmission cooler tubes from the
radiator tank clips.
Fig. 1 Cooling Module Ð 5.9L Gas
1 - TRANS OIL COOLER BYPASS (5.9L only)
2 - OIL COOLER THERMOSTATIC BYPASS VALVE (5.9L only)
3 -TRANS OIL COOLER
4 - OIL COOLER MOUNTING BOLT (4)
5 - POWER STEERING COOLER
6 - POWER STEERING COOLER MOUNTING BOLT(2)
7 - TRANS OIL COOLER OUTLET
8 - TRANS OIL COOLER INLET
9 - COOLER LINE CLIP
10 - COOLER LINE CLIP
11 - RADIATOR
7 - 72 TRANSMISSIONDR