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24 - 56
PLUMBING
A/C EXPANSION VALVE (Continued)
tor ensures that none of the refrigerant leaving the
evaporator is still in a liquid state, which could cause
damage to the compressor.
DIAGNOSIS AND TESTING - A/C EXPANSION
VALVE
The expansion valve is located on the engine side
of the dash panel near the shock tower.
The expansion valve can fail in three different
positions (open, closed or restricted).
In an Open Position: this will result in a noisy
compressor or no cooling. The cause can be broken
spring, broken ball or excessive moisture in the A/C
system. If the spring or ball are found to be defective,
replace the expansion valve. If excessive moisture is
found in the A/C system, recycle the refrigerant.
In a Closed Position: There will be low suction
pressure and no cooling. This may be caused by a
failed power dome or excessive moisture in the A/C
system. If the power dome on the expansion valve is
found to be defective replace the expansion valve. If
excessive moisture is found recycle the refrigerant.
A Restricted Orifice: There will be low suction
pressure and no cooling. This may be caused by
debris in the refrigerant system. If debris is believed
to be the cause, recycle the refrigerant and replace
the expansion valve and the receiver-drier.
REMOVAL
WARNING: REFER TO THE APPLICABLE WARN-
INGS AND CAUTIONS FOR THIS SYSTEM BEFORE
PERFORMING THE FOLLOWING OPERATION (Refer
to 24 - HEATING & AIR CONDITIONING/PLUMBING -
WARNING) and (Refer to 24 - HEATING & AIR CON-
DITIONING/PLUMBING - CAUTION).
(1) Recover the refrigerant from the A/C system-
(Refer to 24 - HEATING & AIR CONDITIONING/
PLUMBING - STANDARD PROCEDURE).
(2) Disconnect and isolate the battery negative
cable.
(3) Remove the nut that secures the suction and
liquid line fittings to the stud on the expansion valve
(Fig. 6).
(4) Disconnect the suction and liquid lines from
the expansion valve.
(5) Remove the seals from the suction and liquid
line fitting and discard.
(6) Install plugs in, or tape over the opened liquid
and suction line fittings and both expansion valve
ports.
(7) Remove the two bolts that secure the expan-
sion valve to the evaporator tube tapping plate.
(8) Remove the expansion valve from the evapora-
tor tube tapping plate.
(9) Remove the seals from the evaporator inlet and
outlet tube fittings and discard.
(10) Install plugs in, or tape over the opened evap-
orator inlet and outlet tube fittings and both expan-
sion valve ports.
Fig. 6 Expansion Valve
1 - EVAPORATOR TUBE TAPPING PLATE
2 - O-RING SEAL (2)
3 - EXPANSION VALVE
4 - BOLT (2)
5 - SUCTION LINE
6 - NUT
7 - LIQUID LINE
8 - O-RING SEAL (2)
INSTALLATION
(1) Remove the tape or plugs from the tapping
plate evaporator inlet and outlet tube fittings and
both ports on the back of the expansion valve.
(2) Lubricate new rubber O-ring seals with clean
refrigerant oil and install them on the tapping plate
evaporator inlet and outlet tube fittings.
(3) Position the expansion valve onto the tapping
plate evaporator inlet and outlet tube fittings.
(4) Install and tighten the two bolts that secure
the expansion valve to the evaporator tube tapping
plate. Tighten the bolts to 5 N·m (45 in. lbs.).
(5) Remove the tape or plugs from the liquid and
suction line fittings and both expansion valve ports.
(6) Lubricate new rubber O-ring seals with clean
refrigerant oil and install them on the liquid and suc-
tion line fittings.
(7) Reconnect the liquid line fitting to the expan-
sion valve.
(8) Reconnect the suction line fitting to the expan-
sion valve.
VA
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