2003 JEEP GRAND CHEROKEE tire bolt

INSTALLATION - 2.7L TURBO DIESEL
WARNING: REVIEW THE WARNINGS AND CAU-
TIONS IN THE FRONT OF THIS SECTION BEFORE
PERFORMING THE FOLLOWING OPERATION.
(Refer to 24 - HEATING & AIR CONDITIONING/
PLUMBING - WARNING) (Refer to 24 - HEATING &
AIR CONDITIONING/PLUMBING - CAUTION)
Any kinks or sharp bends in the refrigerant plumb-
ing will reduce the capacity of the entire air condi-
tioning system. Kinks and sharp bends reduce the
flow of refrigerant in the system. A good rule for the
flexible hose refrigerant lines is to keep the radius of
all bends at least ten times the diameter of the hose.
In addition, the flexible hose refrigerant lines should
be routed so they are at least 80 millimeters (3
inches) from the exhaust manifold.
High pressures are produced in the refrigerant sys-
tem when the air conditioning compressor is operat-
ing. Extreme care must be exercised to make sure
that each of the refrigerant system connections is
pressure-tight and leak free. It is a good practice to
inspect all flexible hose refrigerant lines at least once
a year to make sure they are in good condition and
properly routed.
(1) Carefully position the suction line in the vehi-
cle.
(2) Remove the cap or tape and install the suction
line on the compressor. Be certain the sealing o-ring
is well lubricated with PAG oil and free of tears.
Torque the retaining fastener to 22 N´m (200 in. lbs.).
(3) Position and install the refrigerant line support
bracket bolt on the cylinder head cap. Torque the bolt
to 20 N´m (177 in. lbs.).
(4) Remove the cap or tape and install the suction
line on the H-Valve Block. Be certain the sealing
O-ring is well lubricated with PAG oil and free of
tears. Torque the retaining fastener to 28 N´m (21 ft.
lbs.).
(5) Install the tie-straps retaining the wire har-
ness on the suction line.
(6) Evacuate the refrigerant system. (Refer to 24 -
HEATING & AIR CONDITIONING/PLUMBING -
STANDARD PROCEDURE - REFRIGERANT SYS-
TEM EVACUATE)
(7) Charge the refrigerant system. (Refer to 24 -
HEATING & AIR CONDITIONING/PLUMBING -
STANDARD PROCEDURE - REFRIGERANT SYS-
TEM CHARGE)
(8) Connect the negative battery cable.
A/C EVAPORATOR
DESCRIPTION
The evaporator coil is located in the HVAC hous-
ing, under the instrument panel. The evaporator coil
is positioned in the HVAC housing so that all air that
enters the housing must pass over the fins of the
evaporator before it is distributed through the sys-
tem ducts and outlets. However, air passing over the
evaporator coil fins will only be conditioned when the
compressor is engaged and circulating refrigerant
through the evaporator coil tubes.
OPERATION
Refrigerant enters the evaporator from the orifice
tube as a low-temperature, low-pressure liquid. As
air flows over the fins of the evaporator, the humidity
in the air condenses on the fins, and the heat from
the air is absorbed by the refrigerant. Heat absorp-
tion causes the refrigerant to boil and vaporize. The
refrigerant becomes a low-pressure gas before it
leaves the evaporator.
The evaporator coil cannot be repaired and, if
faulty or damaged, it must be replaced.
REMOVAL
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, DISABLE THE AIRBAG SYSTEM BEFORE
ATTEMPTING ANY STEERING WHEEL, STEERING
COLUMN, OR INSTRUMENT PANEL COMPONENT
DIAGNOSIS OR SERVICE. DISCONNECT AND ISO-
LATE THE BATTERY NEGATIVE (GROUND) CABLE,
THEN WAIT TWO MINUTES FOR THE AIRBAG SYS-
TEM CAPACITOR TO DISCHARGE BEFORE PER-
FORMING FURTHER DIAGNOSIS OR SERVICE. THIS
IS THE ONLY SURE WAY TO DISABLE THE AIRBAG
SYSTEM. FAILURE TO TAKE THE PROPER PRE-
CAUTIONS COULD RESULT IN AN ACCIDENTAL
AIRBAG DEPLOYMENT AND POSSIBLE PERSONAL
INJURY.
WARNING: REVIEW THE WARNINGS AND CAU-
TIONS IN THE FRONT OF THIS SECTION BEFORE
PERFORMING THE FOLLOWING OPERATION.
(Refer to 24 - HEATING & AIR CONDITIONING/
PLUMBING - WARNING) (Refer to 24 - HEATING &
AIR CONDITIONING/PLUMBING - CAUTION)
(1) Remove and disassemble the HVAC housing.
(Refer to 24 - HEATING & AIR CONDITIONING/
DISTRIBUTION/HVAC HOUSING - REMOVAL)
(Refer to 24 - HEATING & AIR CONDITIONING/
DISTRIBUTION/HVAC HOUSING - DISASSEMBLY)
(2) Lift the evaporator coil unit out of the lower
half of the HVAC housing (Fig. 11).
WJPLUMBING 24 - 69
SUCTION LINE (Continued)

VISCOUS HEATER
DESCRIPTION
DESCRIPTION
The diesel engine has an engine mounted mechan-
ical device called a Viscous Heater that is used to
heat the coolant coming from the engine to the
heater core. The Viscous Heater is driven by the
engine fan belt and has a electro-mechanical clutch
which is controlled by the HVAC control unit.
DESCRIPTION - VISCOUS HEATER CLUTCH
The basic viscous heater clutch assembly consists
of a stationary electromagnetic coil, a hub bearing
and pulley assembly and a clutch plate. The electro-
magnetic coil unit and the hub bearing and pulley
assembly are each retained on the nose of the com-
pressor front housing with snap rings (Fig. 17). The
clutch plate is keyed to the viscous heater shaft and
secured with a nut. These components provide the
means to engage and disengage the viscous heater
from the engine accessory drive belt.
OPERATION
OPERATION - VISCOUS HEATER
The Viscous Heater is driven by the engine fan
belt. The Viscous Heater has an electro-mechanical
clutch that receives a signal from the HVAC control
head and the Viscous Heater controller that ener-
gizes and engages the clutch. Once engaged theclutch allows the Viscous Heater to increase the tem-
perature of the coolant flowing to the heater core,
which provides heat the passenger compartment
quicker than normal engines without the Viscous
Heater. The Viscous Heater generates heat by means
of friction which heats a special Silicon Oil within its
housing which is then transferred to the engine cool-
ant when the coolant passes over fins within the
pump. Please note that the coolant is isolated from
the silicon oil within the pump housing. When
demand for passenger compartment heat decreases
the Viscous Heater clutch will receive an input from
the Viscous heater controller to disengage.
OPERATION - VISCOUS HEATER CLUTCH
When the clutch coil is energized, it magnetically
draws the clutch into contact with the pulley and
drives the viscous heater shaft. When the coil is not
energized the pulley freewheels on the clutch hub
bearing, which is part of the pulley. The viscous
heater clutch and coil are the only serviced parts on
the viscous heater assembly. If the viscous heater is
inoperative or damaged the entire assembly must be
replaced. The viscous heater clutch engagement is
controlled by several components: the viscous heater
controller, the engine powertrain control module and
the HVAC control head.
REMOVAL
REMOVAL - VISCOUS HEATER
(1) Drain the engine coolant(Refer to 7 - COOL-
ING/ENGINE - STANDARD PROCEDURE).
(2) Remove the engine accessory drive belt(Refer to
7 - COOLING/ACCESSORY DRIVE/DRIVE BELTS -
REMOVAL).
(3) Remove the heater hose clamps at the Viscous
Heater.
(4) Remove the heater hoses from the Viscous
Heater.
(5) Unplug the Viscous Heater clutch electrical
connector.
(6) Remove the bolts holding the Viscous Heater to
the mounting bracket.
(7) Remove the Viscous Heater from the vehicle.
REMOVAL - VISCOUS HEATER CLUTCH
(1) The viscous heater clutch can be serviced in
the vehicle and the cooling system does not have to
be drained.
(2) Disconnect and isolate the battery negative
cable.
(3) Remove the serpentine drive belt(Refer to 7 -
COOLING/ACCESSORY DRIVE/DRIVE BELTS -
REMOVAL).
Fig. 17 CLUTCH ASSEMBLY- typical
1 - CLUTCH PLATE
2 - SHAFT KEY
3 - PULLEY
4 - COIL
5 - CLUTCH SHIMS
6 - SNAP RING
7 - SNAP RING
24 - 76 PLUMBINGWJ