Jeep Cherokee 2000 Service Manual - page 1911
to hold one side of the connection stationary, while
loosening or tightening the other side of the connec-
tion with a second wrench.
The refrigerant must be recovered completely from
the system before opening any fitting or connection.
Open the fittings with caution, even after the refrig-
erant has been recovered. If any pressure is noticed
as a fitting is loosened, tighten the fitting and
recover the refrigerant from the system again.
Do not discharge refrigerant into the atmosphere.
Use an R-134a refrigerant recovery/recycling device
that meets SAE Standard J2210.
The refrigerant system will remain chemically sta-
ble as long as pure, moisture-free R-134a refrigerant
and refrigerant oil is used. Dirt, moisture, or air can
upset this chemical stability. Operational troubles or
serious damage can occur if foreign material is
present in the refrigerant system.
When it is necessary to open the refrigerant sys-
tem, have everything needed to service the system
ready. The refrigerant system should not be left open
to the atmosphere any longer than necessary. Cap or
plug all lines and fittings as soon as they are opened
to prevent the entrance of dirt and moisture. All lines
and components in parts stock should be capped or
sealed until they are to be installed.
All tools, including the refrigerant recycling equip-
ment, the manifold gauge set, and test hoses should
be kept clean and dry. All tools and equipment must
be designed for R-134a refrigerant.
COMPRESSOR - 2.5L VM DIESEL
DESCRIPTION
The 2.5L diesel engine uses a Denso 10PA17 seven
cylinder, reciprocating wobble plate-type compressor.
This compressor has a fixed displacement of 150
cubic centimeters (9.375 cubic inches), and has both
the suction and discharge ports located on the com-
pressor cylinder head. A label identifying the use of
R-134a refrigerant is located on the compressor.
OPERATION
The compressor is driven by the engine through
the power steering pump main shaft. The power
steering pump is driven by the accessory drive belt.
The compressor is lubricated by refrigerant oil that
is circulated throughout the refrigerant system with
the refrigerant. The compressor draws in low-pres-
sure refrigerant vapor from the evaporator through
its suction port. It then compresses the refrigerant
into a high-pressure, high-temperature refrigerant
vapor, which is then pumped to the condenser
through the compressor discharge port.
The compressor cannot be repaired. If faulty or
damaged, the entire compressor assembly must be
replaced. The compressor clutch, pulley and clutch
coil are available for service.
COMPRESSOR CLUTCH - 2.5L VM DIESEL
DESCRIPTION
The compressor clutch assembly used on the diesel
engine is the same clutch used on most compressors
however, due to the different drive arrangement it
utilizes a drive cup that threads onto the clutch drive
pulley. The basic compressor clutch assembly consists
of a stationary electromagnetic coil, a hub bearing
and pulley assembly, and a clutch plate (Fig. 1). The
electromagnetic coil unit and the hub bearing and
pulley assembly are each retained on the nose of the
compressor front housing with snap rings. The clutch
plate is keyed to the compressor shaft and secured
with a nut. These components provide the means to
engage and disengage the compressor from the
engine serpentine accessory drive belt.
OPERATION
When the clutch coil is energized, it magnetically
draws the clutch into contact with the pulley and
drives the compressor shaft. When the coil is not
energized, the pulley freewheels on the clutch hub
bearing, which is part of the pulley. The compressor
clutch and coil are the only serviced parts on the
compressor.
The compressor clutch engagement is controlled by
several components: the heater-A/C mode control
switch, the low pressure cycling clutch switch, the
dual function high pressure switch, the compressor
Fig. 1 Compressor Clutch – Drive Cup Not Shown
1 – CLUTCH PLATE
2 – SHAFT KEY
3 – PULLEY
4 – COIL
5 – CLUTCH SHIMS
6 – SNAP RING
7 – SNAP RING
XJ
HEATING AND AIR CONDITIONING
24 - 3
DESCRIPTION AND OPERATION (Continued)