2001 DODGE RAM check engine

tracts and creates a vacuum in the cooling system.
This causes the vacuum valve to open and coolant in
the reserve/overflow tank to be drawn through its
connecting hose into radiator. If the vacuum valve is
stuck shut, the radiator hoses will collapse on cool-
down. Clean the vent valve (Fig. 43).
DIAGNOSIS AND TESTINGÐRADIATOR
CAP-TO-FILLER NECK SEAL
The pressure cap upper gasket (seal) pressure
relief can be tested by removing overflow hose from
radiator filler neck nipple. Attach hose of pressure
tester tool 7700 (or equivalent) to nipple. It will be
necessary to disconnect hose from its adapter for
filler neck. Pump air into radiator. The pressure cap
upper gasket should relieve at 69-124 kPa (10-18 psi)
and hold pressure at a minimum of 55 kPa (8 psi).
WARNING: THE WARNING WORDS ÐDO NOT
OPEN HOTÐ ON RADIATOR PRESSURE CAP, ARE
A SAFETY PRECAUTION. WHEN HOT, PRESSURE
BUILDS UP IN COOLING SYSTEM. TO PREVENT
SCALDING OR INJURY, RADIATOR CAP SHOULD
NOT BE REMOVED WHILE SYSTEM IS HOT AND/OR
UNDER PRESSURE.
Do not remove radiator cap at any timeexceptfor
the following purposes:
²Check and adjust antifreeze freeze point
²Refill system with new antifreeze
²Conducting service procedures
²Checking for vacuum leaks
WARNING: IF VEHICLE HAS BEEN RUN RECENTLY,
WAIT AT LEAST 15 MINUTES BEFORE REMOVING
RADIATOR CAP. WITH A RAG, SQUEEZE RADIATOR
UPPER HOSE TO CHECK IF SYSTEM IS UNDER
PRESSURE. PLACE A RAG OVER CAP AND WITH-
OUT PUSHING CAP DOWN, ROTATE IT COUNTER-
CLOCKWISE TO FIRST STOP. ALLOW FLUID TO
ESCAPE THROUGH THE COOLANT RESERVE/
OVERFLOW HOSE INTO RESERVE/OVERFLOW
TANK. SQUEEZE RADIATOR UPPER HOSE TO
DETERMINE WHEN PRESSURE HAS BEEN
RELEASED. WHEN COOLANT AND STEAM STOP
BEING PUSHED INTO TANK AND SYSTEM PRES-
SURE DROPS, REMOVE RADIATOR CAP COM-
PLETELY.
DIAGNOSIS AND TESTINGÐRADIATOR CAP
Remove cap from radiator. Be sure that sealing
surfaces are clean. Moisten rubber gasket with water
and install cap on pressure tester 7700 or an equiv-
alent (Fig. 44).NOTE: Radiator pressure testing tools are very sen-
sitive to small air leaks, which will not cause cool-
ing system problems. A pressure cap that does not
have a history of coolant loss should not be
replaced just because it leaks slowly when tested
with this tool. Add water to tool. Turn tool upside
down and recheck pressure cap to confirm that cap
needs replacement.
Operate tester pump to bring pressure to 104 kPa
(15 psi) on gauge. If pressure cap fails to hold pres-
sure of at least 97 kPa (14 psi) replace cap.
The pressure cap may test properly while posi-
tioned on tool 7700 (or equivalent). It may not hold
pressure or vacuum when installed on radiator. If so,
inspect radiator filler neck and cap's top gasket for
damage. Also inspect for dirt or distortion that may
prevent cap from sealing properly.
CLEANING
Clean radiator pressure cap using a mild soap and
water mixture. DO NOT use any chemicals stronger
than mild soap, damage to the seal can occur .
INSPECTION
Hold cap at eye level, right side up. The vent valve
(Fig. 45) at bottom of cap should open. If rubber gas-
Fig. 44 Pressure Testing Radiator CapÐTypical
Tester
1 - PRESSURE CAP
2 - TYPICAL COOLING SYSTEM PRESSURE TESTER
7 - 66 ENGINEBR/BE
RADIATOR PRESSURE CAP (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)

INSTALLATION
(1) Clean gasket mating surfaces.
(2) Using a new gasket, install water pump to
engine as follows: Guide water pump nipple into
bypass hose as pump is being installed. Install water
pump bolts (Fig. 52). Tighten water pump mounting
bolts to 40 N´m (30 ft. lbs.) torque.
(3) Position bypass hose clamp to bypass hose.
(4) Spin water pump to be sure that pump impel-
ler does not rub against timing chain case/cover.
(5) Install a new o-ring to the heater hose coolant
return tube (Fig. 51). Coat the new o-ring with anti-
freeze before installation.
(6) Install coolant return tube and its mounting
bolt to engine (Fig. 51). Be sure the slot in tube
bracket is bottomed to mounting bolt. This will prop-
erly position return tube.
(7) Connect radiator lower hose to water pump.
(8) Connect heater hose and hose clamp to coolant
return tube.
(9) Install drive belt (Refer to 7 - COOLING/AC-
CESSORY DRIVE/DRIVE BELTS - INSTALLATION)
(Fig. 50).
(10) Position fan shroud and fan blade/viscous fan
drive assembly to vehicle as a complete unit.
(11) Install fan shroud.
(12) Install fan blade/viscous fan drive assembly to
water pump shaft.
(13) Fill cooling system (Refer to 7 - COOLING -
STANDARD PROCEDURE).
(14) Connect negative battery cable.
(15) Start and warm the engine. Check for leaks.
WATER PUMP - 8.0L
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
NOTE: 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 8.0L V-10 engine, a rubber o-ring (instead of
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 negative battery 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.
(4) Remove the four fan shroud mounting bolts at
the radiator (Fig. 53). 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.
Fig. 53 Typical Fan Shroud Mounting
1 - RADIATOR SUPPORT
2 - RADIATOR
3 - BOLTS (4)
4 - FAN SHROUD
7 - 70 ENGINEBR/BE
WATER PUMP - 3.9L/5.2L/5.9L (Continued)

(11) Install fan shroud to radiator. Tighten bolts to
6 N´m (50 in. lbs.) torque.
(12) Install fan blade/viscous fan drive assembly to
water pump shaft.
(13) Fill cooling system (Refer to 7 - COOLING -
STANDARD PROCEDURE).
(14) Connect negative battery cable.
(15) Start and warm the engine. Check for leaks.
WATER PUMP - 5.9L DIESEL
DESCRIPTION
The water pump is mounted to the engine front
cover between the automatic belt tensioner and the
fan drive pulley (Fig. 60).
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
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 (Fig. 60).
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 bolt retaining the wiring harness
near the top of water pump. Position wire harness to
the side.
(4) Remove the accessory drive belt (Refer to 7 -
COOLING/ACCESSORY DRIVE/DRIVE BELTS -
REMOVAL).
(5) Remove water pump mounting bolts (Fig. 61).
(6) Clean water pump sealing surface on cylinder
block.
CLEANING
Clean gasket mating surfaces as necessary.
INSPECTION
Visually inspect the water pump and replace if it
has any of the following conditions:
²The body is cracked or damaged
Fig. 59 Heater Hose Fitting PositionÐ8.0L V-10
1 - HEATER HOSE FITTING
2 - WATER PUMP
Fig. 60 Water PumpÐ5.9L DieselÐTypical (non-A/C
shown)
1 - WATER PUMP
2 - ACCESSORY DRIVE BELT
3 - AUTOMATIC BELT TENSIONER
4 - MOUNT BOLT
5 - 3/89SQUARE HOLE
BR/BEENGINE 7 - 73
WATER PUMP - 8.0L (Continued)

²Water leaks from the shaft seal. This is evident
by traces of coolant below the vent hole
²Loose or rough turning bearing. Also inspect
thermal fan drive
²Impeller rubbing the pump body
INSTALLATION
(1) Install new O-ring seal in groove on water
pump (Fig. 62).
(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 -
3.9L/5.2L/5.9L
REMOVALÐWATER 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. 63) must be partially removed. Removing the
generator 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 24 - HEATING AND AIR CON-
DITIONING.
(1) Disconnect negative battery cable from battery.
(2) Partially drain cooling system (Refer to 7 -
COOLING - STANDARD PROCEDURE).
Fig. 61 Water Pump Removal/Installation
1 - O-RING SEAL (SQUARE)
2 - WATER PUMP
3 - BOLT (2)
Fig. 62 Pump O-ring Seal
1 - O-RING SEAL
2 - GROOVE
3 - WATER PUMP
Fig. 63 GeneratorÐA/C Compressor Mounting
BracketÐTypical
7 - 74 ENGINEBR/BE
WATER PUMP - 5.9L DIESEL (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 7 - COOL-
ING/ACCESSORY DRIVE/DRIVE BELTS - INSTALLA-
TION). The correct belt with the correct length must
be used.(12) Install air cleaner assembly.
(13) Install upper radiator hose to radiator.
(14) Connect throttle cable to clip at radiator fan
shroud.
(15) Connect wiring harness to A/C compressor.
(16) Fill cooling system (Refer to 7 - COOLING -
STANDARD PROCEDURE).
(17) Start and warm the engine. Check for leaks.
INSTALLATIONÐWATER PUMP BYPASS HOSE
WITHOUT AIR CONDITIONING
(1) Position bypass hose clamps to the center of
hose.
(2) Install bypass hose to engine.
(3) Secure both hose clamps.
(4) Fill cooling system (Refer to 7 - COOLING -
STANDARD PROCEDURE).
(5) Start and warm the engine. Check for leaks.
Fig. 72 Tensioner Mounting
1 - DOWEL PIN HOLE
2 - TENSIONER MOUNTING BRACKET
7 - 78 ENGINEBR/BE
WATER PUMP INLET TUBE - 3.9L/5.2L/5.9L (Continued)

(3) Remove the end plug, thermostat and spring
from transmission oil cooler (Fig. 3).
ASSEMBLY
(1) Throughly clean the thermostat bore on the
transmission oil cooler.
(2) Install new spring, thermostat, end plug and
snap ring.
(3) Install transmission oil cooler (Refer to 7 -
COOLING/TRANSMISSION/TRANS COOLER -
INSTALLATION).
INSTALLATION
(1) Install the oil cooler assembly to the A-shaped
radiator support bracket using the two upper mount-
ing bolts and mounting straps. Install the bolts but
do not tighten at this time.
(2) Install the radiator support bracket and oil
cooler (as an assembly) to the vehicle.
(3) Install the two lower radiator A-shaped support
bracket bolts. Do not tighten bolts at this time.
(4) Slide and position the oil cooler on the
A-shaped bracket until its lower mounting hole lines
up with the bolt hole on the vehicle body. Tighten the
oil cooler mounting strap bolts to 6 N´m (50 in. lbs.)
torque.
(5) Install the upper radiator A-shaped support
bracket bolt. Tighten all three radiator support
bracket mounting bolts to 11 N´m (95 in. lbs.) torque.
(6) Inspect quick connect fitting for debris and
install the quick-connect fitting on the cooler outler
tube until an audible ªclickº is heard. Pull apart to
verify connection.
(7) Connect battery negative cable.
(8) Start the engine and check all fittings for
leaks.
(9) Check the fluid level in the automatic trans-
mission (Refer to 21 - TRANSMISSION/TRAN-
SAXLE/AUTOMATIC - 42RE/FLUID - STANDARD
PROCEDURE), (Refer to 21 - TRANSMISSION/
TRANSAXLE/AUTOMATIC - 44RE/FLUID - STAN-
DARD PROCEDURE) or (Refer to 21 -
TRANSMISSION/TRANSAXLE/AUTOMATIC -
46RE/FLUID - STANDARD PROCEDURE).
TRANS COOLER - 8.0L
DESCRIPTION
The air-to-oil cooler is located in front of and to the
left side of the radiator (Fig. 4). This cooler is sup-
plied as standard equipment on all models equipped
with an automatic transmission.
OPERATION
The transmission oil is routed through the cooler
where the cooler removes heat from the transmission
fluid, before returning to the transmission.
Fig. 2 Transmission Oil CoolerÐ3.9/5.2/5.9L Engines
1 - UPPER RADIATOR SUPPORT BRACKET BOLT
2 - MOUNTING STRAPS (2)
3 - TRANS. OIL COOLER UPPER MOUNTING BOLTS (2)
4 - TRANS. OIL COOLER LOWER MOUNTING BOLT
5 - LOWER RADIATOR SUPPORT BRACKET BOLTS (2)
6 - TRANSMISSION OIL COOLER
7 - RADIATOR SUPPORT BRACKET
Fig. 3 Transmission Oil Cooler Thermostat
Removal/Installation
1 - THERMOSTAT HOUSING
2 - SPRING
3 - END PLUG
4 - SNAP RING
5 - THERMOSTAT
7 - 82 TRANSMISSIONBR/BE
TRANS COOLER - 3.9L/5.2L/5.9L (Continued)

INSTALLATION
(1) Install the oil cooler and cooler line assembly to
the vehicle.
(2) Install three mounting bolts and tighten to 6
N´m (50 in. lbs.) torque.
(3) Connect the transmission cooling lines to the
oil cooler by pushing the rubber hoses onto the oil
cooler tubes. Tighten the worm gear clomps to 2 N´m
(18 in. lbs.)
(4) Start the engine and check all fittings for
leaks.
(5) Check the fluid level in the automatic trans-
mission (Refer to 21 - TRANSMISSION/TRAN-
SAXLE/AUTOMATIC - 47RE/FLUID - STANDARD
PROCEDURE).
TRANS COOLER - 5.9L DIESEL
DESCRIPTION
All diesel models equipped with an automatic
transmission are equipped with both a main water-
to-oil cooler and a separate air-to-oil cooler. Both cool-
ers are supplied as standard equipment on diesel
engine powered models when equipped with an auto-
matic transmission.
The main water-to-oil transmission oil cooler is
mounted to a bracket on the turbocharger side of the
engine (Fig. 6).
The air-to-oil cooler is located in front of and to the
left side of the radiator (Fig. 7).
OPERATION
The transmission oil is routed through the main
cooler first, then the auxiliary cooler where addi-
tional heat is removed from the transmission oil
before returning to the transmission.
STANDARD PROCEDURE - FLUSHING
COOLERS AND TUBES - WITH RADIATOR
IN-TANK TRANSMISSION OIL COOLER
When a transmission failure has contaminated the
fluid, the oil cooler(s) must be flushed. The torque
converter must also be replaced. This will insure that
metal particles or sludged oil are not later trans-
ferred back into the reconditioned (or replaced) trans-
mission.
The only recommended procedure for flushing cool-
ers and lines is to use Tool 6906-B Cooler Flusher.
Fig. 6 Transmission Water-To-Oil CoolerÐDiesel
EngineÐTypical
1 - TRANSMISSION WATER-TO-OIL COOLER
Fig. 7 Auxiliary Transmission Oil CoolerÐDiesel
Engine
1 - CHARGE AIR COOLER (INTERCOOLER)
2 - QUICK-CONNECT FITTINGS (2)
3 - MOUNTING NUTS (2)
4 - MOUNTING BOLT
5 - TRANSMISSION OIL COOLER
BR/BETRANSMISSION 7 - 85
TRANS COOLER - 8.0L (Continued)