INSTALLATION
NOTE: Be certain to add refrigerant oil if the rear
A/C evaporator is being replaced. The refrigerant oil
must be drained from the old evaporator and mea-
sured to determine the amount of refrigerant oil to
add to the new evaporator. Use only refrigerant oil
of the type recommended for the rear A/C compres-
sor in the vehicle.
(1) If the rear A/C evaporator is being replaced,
install the correct amount and type of refrigerant oil
into the new rear A/C evaporator. Drain the old evap-
orator and measure the refrigerant oil. Fill the new
evaporator with the same amount of new refrigerant
oil that was drained out of the old evaporator.
(2) Position the rear A/C evaporator to the bottom
of the rear A/C evaporator housing and install four
new rivets.
(3) Position the three covers to the rear A/C evap-
orator and install eight new rivets.
(4) Install the left blower motor onto the rear A/C
evaporator housing (Refer to 24 - HEATING & AIR
CONDITIONING/DISTRIBUTION - REAR/BLOWER
MOTOR - INSTALLATION).
(5) Connect the rear A/C expansion valve to the
rear A/C evaporator and install new insulating tape
(Refer to 24 - HEATING & AIR CONDITIONING/
PLUMBING/REAR
A/C
EXPANSION
VALVE
-
INSTALLATION).
(6) Position the condensate drain pan to the bot-
tom of the rear A/C evaporator and install the five
screws and washers that secure the drain pan to the
evaporator. Tighten the screws to 2.2 N·m (20 in.
lbs.).
(7) Install the rear A/C evaporator housing (Refer
to 24 - HEATING & AIR CONDITIONING/DISTRI-
BUTION/REAR A/C EVAPORATOR HOUSING -
INSTALLATION).
REAR A / C EXPANSION VALVE
DESCRIPTION
The rear A/C expansion valve controls the amount
of refrigerant entering the rear A/C evaporator (Fig.
24). The rear A/C expansion valve is of an externally-
equalized thermostatic expansion valve (TXV) design
and consists of a cast metal body with a removable
equalizer tube and an integral thermal sensor which
uses a capillary tube and sensing bulb.
The rear A/C expansion valve is located to the left
of the rear blower motors in the rear evaporator
housing.
OPERATION
High-pressure, high temperature liquid refrigerant
from the liquid line passes through the expansion
valve orifice, converting it into a low-pressure, low-
temperature mixture of liquid and gas before it
enters the A/C evaporator. A thermal sensor in the
rear A/C expansion valve monitors the temperature
of the refrigerant leaving the rear evaporator by use
of a sensing bulb positioned next to the evaporator
outlet tube. The thermal sensor adjusts the orifice
size at the evaporator inlet to allow the proper
amount of refrigerant into the rear A/C evaporator in
order to meet vehicle cooling requirements. Control-
ling the refrigerant flow through the A/C evaporator
ensures that none of the refrigerant leaving the evap-
orator is still in a liquid state, which could cause
damage to the A/C compressor.
To overcome the effect of the pressure drop within
the rear A/C evaporator, an external equalizer tube is
connected to the evaporator outlet tube and runs to
the underside if the diaphragm within the expansion
valve.
The rear A/C expansion valve is factory calibrated
and cannot be adjusted or repaired and, if faulty or
damaged, it must be replaced.
Fig. 24 Rear A/C Expansion Valve
1 - REAR A/C EXPANSION VALVE
2 - EQUALIZER TUBE
3 - CAPILLARY TUBE
4 - SENSING BULB
VA
PLUMBING
24 - 85