2002 JEEP GRAND CHEROKEE Power steering

CONDITION POSSIBLE CAUSES CORRECTION
BELT BROKEN (NOTE: IDENTIFY
AND CORRECT PROBLEM
BEFORE NEW BELT IS
INSTALLED)1. Excessive tension. 1. Replace belt and automatic belt
tensioner.
2. Incorrect belt. 2. Replace belt.
3. Tensile member damaged during
belt installation.3. Replace belt.
4. Severe misalignment. 4. Check and replace.
5. Bracket, pulley, or bearing failure. 5. Replace defective component
and belt.
NOISE (OBJECTIONABLE
SQUEAL, SQUEAK, OR RUMBLE
IS HEARD OR FELT WHILE
DRIVE BELT IS IN OPERATION)1. Belt slippage. 1. Replace belt or automatic belt
tensioner.
2. Bearing noise. 2. Locate and repair.
3. Belt misalignment. 3. Replace belt.
4. Belt-to-pulley mismatch. 4. Install correct belt.
REMOVAL - 4.7L ENGINE
NOTE: The belt routing schematics are published
from the latest information available at the time of
publication. If anything differs between these sche-
matics and the Belt Routing Label, use the sche-
matics on Belt Routing Label. This label is located
in the engine compartment.
CAUTION: DO NOT LET TENSIONER ARM SNAP
BACK TO THE FREEARM POSITION, SEVERE DAM-
AGE MAY OCCUR TO THE TENSIONER.
Belt tension is not adjustable. Belt adjustment is
maintained by an automatic ( spring load ) belt ten-
sioner.
(1) Disconnect negative battery cable from battery.
(2) Rotate belt tensioner until it contacts its stop.
Remove belt, then slowly rotate the tensioner into
the freearm position. (Fig. 7).
Fig. 7 Belt Routing - 4.7L
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
7 - 22 ACCESSORY DRIVEWJ
DRIVE BELTS - 4.7L (Continued)

(1) Position sensor into the coolant recovery pres-
sure container (Fig. 1).
(2) Connect the coolant level sensor electrical con-
nector (Fig. 2).
(3) Close hood.
COOLANT RECOVERY PRESS
CONTAINER
DESCRIPTION
This system works along with the radiator pres-
sure cap. This is done by using thermal expansion
and contraction of the coolant to keep the coolant
free of trapped air. It provides:
²A volume for coolant expansion and contraction.
²A convenient and safe method for checking/ad-
justing coolant level at atmospheric pressure. This is
done without removing the radiator pressure cap.
²Some 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.
The coolant reservoir/overflow system has a radia-
tor mounted pressurized cap, an overflow tube and a
plastic coolant reservoir/overflow tank (Fig. 3)
mounted to the right inner fender.
RADIATOR FAN - 4.7L
DESCRIPTION
The hydraulic fan (Fig. 4) used on vehicles
equipped the 4.7L engine, replaces both the electric
fan and the engine driven mechanical fan. The
hydraulic cooling fan is integral to the fan shroud
and is located between the radiator and the engine.
The power steering pump supplies the hydraulic
fluid and pressure to rotate the cooling fan blade,
while the electrical part of the fan is controlled by
the JTEC.
The hydraulic fan drive (motor) consists of the
three major following components:
²Steering flow control valve
Fig. 1 COOLANT LEVEL SENSOR ELECTRICAL
CONNECTOR
Fig. 2 COOLANT LEVEL SENSOR REMOVAL/
INSTALLATION
Fig. 3 Coolant Reservoir / Overflow Tank
1 - COOLANT OVERFLOW HOSE
2 - COOLANT RESERVOIR/OVERFLOW TANK
3 - COOLANT LEVEL SENSOR
4 - BOLT
WJENGINE 7 - 27
COOLANT LEVEL SENSOR (Continued)

²Fan control valve
²Two stage G-rotor hydraulic drive
The hydraulic fan and drive is not serviceable.
Therefore any failure of the fan blade, hydraulic fan
drive or fan shroud requires replacement of the fan
module because the fan blade and hydraulic fan drive
are matched and balanced as a system and servicing
either separately would disrupt this balance.
For hydraulic fluid routing information refer to
(Fig. 5).
CAUTION: Do not attempt to service the hydraulic
cooling fan or fan drive separately replace the cooling
module as an assembly. Failure to do so may cause
severe damage to the hydraulic cooling fan assembly.
OPERATION
The hydraulic radiator cooling fan used on the
Grand Cherokee with the 4.7L engine replaces both
the electric fan and the engine driven mechanical
fan. The use of this hydraulic fan provides the 4.7L
equipped Grand Cherokee with heavy trailer tow
capability while at the same time reducing unneces-
sary power drain on both the engine and the vehicles
electrical system.
HYDRAULIC FAN STRATEGY
The hydraulic radiator cooling fan is controlled by
the JTEC. A PWM (Pulse With Modulated) signal
from the JTEC controls the fan from 0 to 100% of the
available fan speed. There are four inputs to the
JTEC that determine what speed percentage of fan is
required by the vehicle. These inputs are:
²Engine Coolant Temperature
²Transmission Oil Temperature
²Battery Temperature
²A/C System Pressure
By monitoring these four parameters, the JTEC
can determine if cooling airflow is required. If airflow
is required, the JTEC will slowly ramp up (speed up)
the fan speed until the parameter(s) are under con-
trol. Once the temperature or pressure is reduced to
within operating parameters the fan will ramp up,
ramp down, or hold its speed to maintain the temper-
ature / pressure requirements.
NOTE: Even if the JTEC is not requesting fan on
operation the fan blade will usually spin between
100 and 500 RPM when the vehicle is at idle. This is
due to a controlled minimum oil flow requirement
through the fan drive motor.
ACTIVATING THE HYDRAULIC FAN WITH THE DRB
Under the Engine Systems test heading, there is a
subheading. ªHydraulic fan solenoid testº, that has
the selections, on /off. Activating the fan with the
DRB will run the fan at 100% duty cycle, which will
help troubleshoot any system problems, and also help
with the deaeration procedure.
NOTE: Engine must be running to activate the fan
with the DRB.
RADIATOR COOLING FAN HYDRAULIC FLUID PATH
Hydraulic fluid is pumped through the power
steering pump, from the pump the fluid travels
though a high pressure delivery line to the fan drive
motor. As fluid is diverted through the G-rotors, rota-
tional motion is created as fluid moves from the high-
pressure (inlet) side of the motor to the low-pressure
(outlet) side. Fluid exiting the drive motor is divided
into two paths. Path one continues through a high
pressure delivery line to the vehicles steering gear to
provide steering assist. and path two sends fluid
back to the power steering pump through a low pres-
sure line. Fluid exits the steering gear under low
pressure and travels through a low pressure line to
the power steering fluid cooler to be cooled before
being returned back the the power steering fluid res-
ervoir (Fig. 5).
Fig. 4 HYDRAULIC RADIATOR COOLING FAN AND
FAN DRIVE
1 - POWER STEERING FLUID COOLER
2 - RADIATOR
3 - HIGH PRESSURE LINE FROM STEERING GEAR PUMP TO
HYDRAULIC FAN MOTOR
4 - HYDRAULIC FAN MOTOR
5 - HIGH PRESSURE LINE FROM HYDRAULIC FAN MOTOR TO
STEERING GEAR
6 - FAN SHROUD
7 - 28 ENGINEWJ
RADIATOR FAN - 4.7L (Continued)

NOTE: There is a steering flow control valve located
in the fan drive motor. This valve operates like the
flow control valve found in the typical power steer-
ing pump. Because of the design of the valve steer-
ing assist can not be effected by the radiator
cooling fan even during fan drive failure.
REMOVAL
(1) Raise vehicle on hoist.
(2) Drain cooling system.(Refer to 7 - COOLING -
STANDARD PROCEDURE)
NOTE: The hydraulic fan drive is driven by the
power steering pump. When removing lines or
hoses from fan drive assembly use a drain pan to
catch any power steering fluid that may exit the fan
drive or the lines and hoses.NOTE: When ever the high pressure line fittings are
removed from the hydraulic fan drive the O-rings
must be replaced.
(3) Disconnect two high pressure lines at hydraulic
fan drive (Fig. 6). Remove and discard o-rings from
line fittings.
(4) Disconnect low pressure return hose at hydrau-
lic fan drive (Fig. 6).
NOTE: The lower mounting bolts can only be
accessed from under vehicle.
(5) Remove two lower mounting bolts from the
shroud (Fig. 8).
(6) Lower vehicle.
(7) Disconnect the electrical connector for the fan
control solenoid.
(8) Disconnect the radiator upper hose at the radi-
ator and position out of the way.
(9) Disconnect the power steering gear outlet hose
and fluid return hose at the cooler (Fig. 7).
Fig. 5 HYDRAULIC FAN FLUID FLOW CIRCUIT
1 - POWER STEERING RESERVOIR
2 - POWER STEERING PUMP
3 - HYDRAULIC FAN DRIVE ASSEMBLY
4 - FAN BLADE5 - HYDRAULIC FAN CONTROL SOLENOID
6 - POWER STEERING OIL COOLER
7 - STEERING GEAR
WJENGINE 7 - 29
RADIATOR FAN - 4.7L (Continued)

(10) Remove two upper mounting bolts from the
shroud (Fig. 8).
(11) Remove the shroud and fan drive from vehi-
cle.
CLEANING
Clean the fan blades using a mild soap and water.
Do not use an abrasive to clean the blades.
INSTALLATION
CAUTION: There is an external ground wire con-
nected to the hydraulic fan drive located at the elec-
trical connector on the fan assembly. This ground
MUST remain connected at all times. Failure to
ensure ground wire is connected when engine is
operating can cause severe damage to the JTEC
module.
(1) Position fan drive and shroud in vehicle.
(2) Install fan shroud upper mounting bolts. Do
not tighten at this time.
(3) Install radiator upper hose onto radiator.
(4) Connect power steering cooler hoses.
(5) Raise vehicle on hoist.
(6) Install fan shroud lower mounting bolts.
Tighten to 6 N´m (50 in. lbs.).
Fig. 6 HYDRAULIC LINES/HOSES AND ELECTRICAL
CONNECTOR
1 - LOW PRESSURE RETURN HOSE
2 - HIGH PRESSURE LINE (OUTLET)
3 - HIGH PRESSURE LINE (INLET)
4 - HYDRAULIC FAN DRIVE
Fig. 7 POWER STEERING GEAR OUTLET AND
RETURN HOSES
1 - POWER STEERING COOLER RETURN HOSE
2 - POWER STEERING COOLER SUPPLY HOSE
Fig. 8 FAN SHROUD MOUNTING BOLT LOCATIONS
1 - FAN SHROUD UPPER MOUNTING BOLT LOCATIONS
2 - FAN SHROUD LOWER MOUNTING BOLT LOCATIONS
7 - 30 ENGINEWJ
RADIATOR FAN - 4.7L (Continued)

NOTE: When ever the high pressure line fittings are
removed from the hydraulic fan drive the o-rings
located on the fittings must be replaced.
(7) Lubricate the o-rings on the fittings with power
steering fluid then connect inlet and outlet high pres-
sure lines to fan drive (Fig. 9). Tighten inlet line to
49 N´m (36 ft. lbs.) tighten outlet line to 29 N´m (21.5
ft. lbs.).
(8) Connect low pressure return hose to fan drive
(Fig. 9).
(9) Lower vehicle.
(10) Install radiator upper hose.
(11) Connect electrical connector for hydraulic fan
control solenoid.
(12) Tighten fan shroud upper mounting bolts to 6
N´m (50 in. lbs.).
(13) Refill cooling system (Refer to 7 - COOLING -
STANDARD PROCEDURE).
CAUTION: Do not run engine with power steering
fluid below the full mark in the reservoir. Sever
damage to the hydraulic cooling fan or the engine
can occur.(14) Refill power steering fluid reservoir and bleed
air from steering system (Refer to 19 - STEERING/
PUMP - STANDARD PROCEDURE).
(15) Run engine and check for leaks.
RADIATOR FAN - 4.0L
DESCRIPTION
The radiator cooling fan used on the 4.0L engine is
an hybrid fan design. The hybrid fan system consist
of a low speed viscous driven mechanical fan and a
electrical fan (Fig. 10).
REMOVAL
(1) Disconnect negative battery cable from battery.
(2) The thermal viscous fan drive/fan blade assem-
bly is attached (threaded) to water pump hub shaft.
Remove fan blade/viscous fan drive assembly from
water pump by turning mounting nut counterclock-
wise as viewed from front (Fig. 11). Threads on vis-
cous fan drive areRIGHT HAND.
(3) Do not attempt to remove fan/viscous fan drive
assembly from vehicle at this time.
(4) Do not unbolt fan blade assembly from viscous
fan drive at this time.
(5) Remove fan shroud-to-upper crossmember nuts.
(6) Remove fan shroud and fan blade/viscous fan
drive assembly as a complete unit from vehicle.
Fig. 9 HYDRAULIC LINES/HOSES AND ELECTRICAL
CONNECTOR
1 - LOW PRESSURE RETURN HOSE
2 - HIGH PRESSURE LINE (OUTLET)
3 - HIGH PRESSURE LINE (INLET)
4 - HYDRAULIC FAN DRIVEFig. 10 Radiator Cooling Fan
1 - RADIATOR
2 - ELECTRIC COOLING FAN CONNECTOR
3 - FAN SHROUD
4 - ELECTRIC COOLING FAN
WJENGINE 7 - 31
RADIATOR FAN - 4.7L (Continued)

(4) Remove two radiator mounting bolts.
(5) Disconnect both transmission cooler lines from
radiator.
(6) Disconnect electrical connector for the fan con-
trol solenoid.
(7) Disconnect the power steering cooler line from
cooler and filter.
(8) Disconnect the radiator upper and lower hoses.
(9) Disconnect the overflow hose from radiator.
(10) Remove the air inlet duct at the grill.(11) The lower part of radiator is equipped with
two alignment dowel pins (Fig. 35). They are located
on the bottom of radiator tank and fit into rubber
grommets. These rubber grommets are pressed into
the radiator lower crossmember.
WARNING: THE AIR CONDITIONING SYSTEM (IF
EQUIPPED) IS UNDER A CONSTANT PRESSURE
EVEN WITH THE ENGINE OFF. REFER TO REFRIG-
ERANT WARNINGS IN, HEATING AND AIR CONDI-
TIONING BEFORE HANDLING ANY AIR
CONDITIONING COMPONENT.
NOTE: The radiator and radiator cooling fan can be
removed as an assembly. It is not necessary to
remove the cooling fan before removing or install-
ing the radiator.
(12) Disconnect the two high pressure fluid lines
at the hydraulic fan drive.
(13) Disconnect the low pressure return hose at
the hydraulic fan drive.
(14) Gently lift up and remove radiator from vehi-
cle. Be careful not to scrape the radiator fins against
any other component. Also be careful not to disturb
the air conditioning condenser (if equipped).
CLEANING
Clean radiator fins With the engine cold, apply cold
water and compressed air to the back (engine side) of
Fig. 32 Hose Clamp Tool - Typical
1 - HOSE CLAMP TOOL 6094
2 - HOSE CLAMP
Fig. 33 Clamp Number/Letter Location - Typical
1 - TYPICAL CONSTANT TENSION HOSE CLAMP
2 - CLAMP NUMBER/LETTER LOCATION
3 - TYPICAL HOSE
Fig. 34 Air Seals - Typical
1 - AIR DAM
2 - RADIATOR
3 - AIR DAM
4 - A/C CONDENSER
5 - AIR SEAL
WJENGINE 7 - 43
RADIATOR - 4.7L (Continued)

the radiator to flush the radiator and/or A/C con-
denser of debris.
INSPECTION
The radiator cooling fins should be checked for
damage or deterioration. Inspect cooling fins to make
sure they are not bent or crushed, these areas result
in reduced heat exchange causing the cooling system
to operate at higher temperatures. Inspect the plastic
end tanks for cracks, damage or leaks.
Inspect the radiator neck for damage or distortion.
INSTALLATION
CAUTION: Before installing the radiator or A/C con-
denser, be sure the radiator-to-body and radiator-to-
A/C condenser rubber air seals (Fig. 39) are
properly fastened to their original positions. These
are used at the top, bottom and sides of the radia-
tor and A/C condenser. To prevent overheating,
these seals must be installed to their original posi-
tions.
(1) Equipped with air conditioning: Gently lower
the radiator and fan shroud into the vehicle. Guide
the two radiator alignment dowels through the holes
in the rubber air seals first and then through the A/C
support brackets (Fig. 40). Continue to guide thealignment dowels into the rubber grommets located
in lower radiator crossmember. The holes in the
L-shaped brackets (located on bottom of A/C con-
denser) must be positioned between bottom of rubber
air seals and top of rubber grommets.
(2) Connect the radiator upper and lower hoses
and hose clamps to radiator.
CAUTION: The tangs on the hose clamps must be
positioned straight down.
(3) Install coolant reserve/overflow tank hose at
radiator.
(4) Connect both transmission cooler lines at the
radiator.
(5) Install both radiator mounting bolts.
(6) Install air inlet duct at grill.
(7) Attach electric connector for hydraulic fan con-
trol solenoid.
(8) Install the grill (Refer to 23 - BODY/EXTERI-
OR/GRILLE - INSTALLATION).
(9) Connect the two high pressure lines to the
hydraulic fan drive. Tighten
1¤2in. pressure line fit-
ting to 49 N´m (36 ft. lbs.). and the 3/8 in. pressure
line fitting to 29 N´m (21.5 ft. lbs.).
(10) Connect the low pressure hose to the hydrau-
lic fan drive. Position the spring clamp.
(11) Connect the power steering filter hoses to the
filter. Install new hose clamps.
(12) Rotate the fan blades (by hand) and check for
interference at fan shroud.
(13) Refill cooling system (Refer to 7 - COOLING -
STANDARD PROCEDURE).
(14) Refill the power steering reservoir and bleed
air from system (Refer to 19 - STEERING/PUMP -
STANDARD PROCEDURE).
(15) Connect battery cable at battery.
(16) Start and warm engine. Check for leaks.
RADIATOR - 4.0L
DESCRIPTION
All vehicles are equipped with a cross flow type
radiator with plastic side tanks (Fig. 36).
Plastic tanks, while stronger than brass, are sub-
ject to damage by impact, such as from tools or
wrenches. Handle radiator with care.
REMOVAL
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. REFER TO COOLING SYSTEM DRAIN-
ING.
Fig. 35 Radiator Alignment Dowels - Typical
1 - RADIATOR
2 - ALIGNMENT DOWEL
3 - RADIATOR LOWER ISOLATOR
4 - RADIATOR LOWER CROSSMEMBER
7 - 44 ENGINEWJ
RADIATOR - 4.7L (Continued)