Removal; Installation; A/C Orifice Tube - Dodge Dakota Sport 2001 Service Manual

24 - 40 PLUMBING
A/C EVAPORATOR (Continued)
OPERATION
Refrigerant enters the evaporator from the fixed
orifice tube as a low-temperature, low-pressure liq-
uid. 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
absorption causes the refrigerant to boil and vapor-
ize. The refrigerant becomes a high-pressure gas
when 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.
FAILURE TO TAKE THE PROPER PRECAUTIONS
COULD RESULT IN ACCIDENTAL AIRBAG DEPLOY-
MENT AND POSSIBLE PERSONAL INJURY.
(1) Remove the heater-A/C housing from the vehi-
cle (Refer to 24 - HEATING & AIR CONDITIONING/
DISTRIBUTION/HVAC HOUSING - REMOVAL).
(2) Remove the upper housing cover (Refer to 24 -
HEATING & AIR CONDITIONING/DISTRIBUTION/
HVAC HOUSING - DISASSEMBLY).
(3) Lift the evaporator coil out of the heater-A/C
housing.

INSTALLATION

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.
FAILURE TO TAKE THE PROPER PRECAUTIONS
COULD RESULT IN ACCIDENTAL AIRBAG DEPLOY-
MENT AND POSSIBLE PERSONAL INJURY.
NOTE: If the evaporator is replaced, add 60 millili-
ters (2 fluid ounces) of refrigerant oil to the refrig-
erant system.
(1) Insert the evaporator coil into the bottom of the
heater-A/C housing.
(2) Reassemble the heater-A/C housing (Refer to
24 - HEATING & AIR CONDITIONING/DISTRIBU-
TION/HVAC HOUSING - ASSEMBLY).
(3) Install the heater-A/C housing into the vehicle
(Refer to 24 - HEATING & AIR CONDITIONING/
DISTRIBUTION/HVAC
TION).

A/C ORIFICE TUBE

DESCRIPTION
The fixed orifice tube is installed in the liquid line
between the outlet of the condenser and the inlet of
the evaporator. The fixed orifice tube is located near
the front end of the rear half of the two-piece liquid
line. It is accessed for service by separating the tube
fitting that joins the two halves of the liquid line.
OPERATION
The inlet end of the fixed orifice tube has a nylon
mesh filter screen, which filters the refrigerant and
helps to reduce the potential for blockage of the
metering orifice by refrigerant system contaminants
(Fig. 4). The outlet end of the tube has a nylon mesh
diffuser screen. The O-rings on the plastic body of
the fixed orifice tube seal the tube to the inside of
the liquid line and prevent the refrigerant from
bypassing the fixed metering orifice.
Fig. 4 Fixed Orifice Tube - Typical
1 - DIFFUSER SCREEN
2 - "O" RINGS
3 - INLET FILTER SCREEN
4 - ORIFICE
The fixed orifice tube is used to meter the flow of
liquid refrigerant into the evaporator coil. The high-
pressure liquid refrigerant from the condenser
expands into a low-pressure liquid as it passes
through the metering orifice and diffuser screen of
the fixed orifice tube.
The fixed orifice tube cannot be repaired and, if
faulty or plugged, it must be replaced.
HOUSING - INSTALLA-
AN