Jeep Cherokee 2000 Service Manual - page 1910
CAUTION:
•
Liquid refrigerant is corrosive to metal sur-
faces. Follow the operating instructions supplied
with the service equipment being used.
•
Never
add
R-12
to
a
refrigerant
system
designed to use R-134a. Damage to the system will
result.
•
R-12 refrigerant oil must not be mixed with
R-134a refrigerant oil. They are not compatible.
•
Do not use R-12 equipment or parts on the
R-134a system. Damage to the system will result.
•
Do not overcharge the refrigerant system. This
will cause excessive compressor head pressure
and can cause noise and system failure.
•
Recover the refrigerant before opening any fit-
ting or connection. Open the fittings with caution,
even after the system has been discharged. Never
open or loosen a connection before recovering the
refrigerant.
•
Do not remove the secondary retention clip
from any spring-lock coupler connection while the
refrigerant system is under pressure. Recover the
refrigerant before removing the secondary retention
clip. Open the fittings with caution, even after the
system has been discharged. Never open or loosen
a connection before recovering the refrigerant.
•
The refrigerant system must always be evacu-
ated before charging.
•
Do not open the refrigerant system or uncap a
replacement component until you are ready to ser-
vice the system. This will prevent contamination in
the system.
•
Before disconnecting a component, clean the
outside of the fittings thoroughly to prevent con-
tamination from entering the refrigerant system.
•
Immediately after disconnecting a component
from the refrigerant system, seal the open fittings
with a cap or plug.
•
Before connecting an open refrigerant fitting,
always install a new seal or gasket. Coat the fitting
and seal with clean refrigerant oil before connect-
ing.
•
Do not remove the sealing caps from a replace-
ment component until it is to be installed.
•
When installing a refrigerant line, avoid sharp
bends that may restrict refrigerant flow. Position the
refrigerant lines away from exhaust system compo-
nents or any sharp edges, which may damage the
line.
•
Tighten refrigerant fittings only to the specified
torque. The aluminum fittings used in the refriger-
ant system will not tolerate overtightening.
•
When disconnecting a refrigerant fitting, use a
wrench on both halves of the fitting. This will pre-
vent twisting of the refrigerant lines or tubes.
•
Refrigerant oil will absorb moisture from the
atmosphere if left uncapped. Do not open a con-
tainer of refrigerant oil until you are ready to use it.
Replace the cap on the oil container immediately
after using. Store refrigerant oil only in a clean, air-
tight, and moisture-free container.
•
Keep service tools and the work area clean.
Contamination of the refrigerant system through
careless work habits must be avoided.
COOLING SYSTEM REQUIREMENTS
To maintain the performance level of the heating-
air conditioning system, the engine cooling system
must be properly maintained. The use of a bug
screen is not recommended. Any obstructions in front
of the radiator or condenser will reduce the perfor-
mance of the air conditioning and engine cooling sys-
tems.
The engine cooling system includes the heater core
and the heater hoses. Refer to Group 7 - Cooling Sys-
tem for more information before the opening of, or
attempting any service to the engine cooling system.
REFRIGERANT HOSES/LINES/TUBES
PRECAUTIONS
Kinks or sharp bends in the refrigerant plumbing
will reduce the capacity of the entire system. High
pressures are produced in the system when it is oper-
ating. Extreme care must be exercised to make sure
that all refrigerant system connections are pressure
tight.
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. Sharp bends will reduce the
flow of refrigerant. The flexible hose lines should be
routed so they are at least 80 millimeters (3 inches)
from the exhaust manifold. It is a good practice to
inspect all flexible refrigerant system hose lines at
least once a year to make sure they are in good con-
dition and properly routed.
There are two types of refrigerant fittings:
•
All fittings with O-rings need to be coated with
refrigerant oil before installation. Use only O-rings
that are the correct size and approved for use with
R-134a refrigerant. Failure to do so may result in a
leak.
•
Unified plumbing connections with gaskets can-
not be serviced with O-rings. The gaskets are not
reusable and new gaskets do not require lubrication
before installing.
Using the proper tools when making a refrigerant
plumbing connection is very important. Improper
tools or improper use of the tools can damage the
refrigerant fittings. Always use two wrenches when
loosening or tightening tube fittings. Use one wrench
24 - 2
HEATING AND AIR CONDITIONING
XJ
DESCRIPTION AND OPERATION (Continued)