AC Orifice Tube

Replace the AC orifice tube to restore proper refrigerant flow and AC system performance. This involves recovering refrigerant, disconnecting AC lines, extracting the old orifice tube, and recharging the system.

Warnings

Tools required

Parts

• AC orifice tube × 1 — Use OEM specification
• AC line O-rings × 4 — Use OEM specification
• PAG 46 refrigerant oil × 1 — Use OEM specification

Preparation

1. Park vehicle on level surface and set parking brake
2. Allow engine to cool completely if recently run
3. Connect AC recovery machine and fully recover all R-134a refrigerant from system per EPA regulations
4. Record amount of refrigerant recovered for proper recharge quantity
5. Disconnect negative battery cable to prevent accidental compressor engagement
6. Locate the liquid line connection near the firewall on passenger side - orifice tube is inside this line

Procedure

1. 1

   Access the liquid line connection
   Open hood and locate the AC liquid line near the firewall on the passenger side. The orifice tube is located inside the liquid line at the evaporator inlet connection. Clean the area around the connection fittings thoroughly to prevent debris from entering the system.
2. 2

   Disconnect the liquid line fitting
   Using a line wrench, carefully loosen and disconnect the liquid line fitting at the evaporator inlet. Support the line to avoid bending. Cap or plug both open ends immediately to prevent moisture and debris entry. Some residual refrigerant oil will drain out - this is normal.
   ⚠Even after recovery, some refrigerant may remain. Wear safety glasses and work in ventilated area
3. 3

   Remove the orifice tube
   Insert the orifice tube removal tool into the liquid line opening. The orifice tube has small tabs - hook these with the removal tool and carefully pull straight out. If the tube is stuck, gently rotate while pulling. Do not use excessive force as this can break the tube and leave debris in the line.
   ⚠If orifice tube breaks during removal, all pieces must be recovered. Inspect line carefully with flashlight
4. 4

   Inspect the old orifice tube
   Examine the removed orifice tube for metal shavings, debris, or discoloration. Metal debris indicates compressor failure and requires additional system service. Check the screen for contamination. If heavily contaminated, inspect compressor and consider condenser replacement.
5. 5

   Clean the liquid line
   Use compressed air or refrigerant-approved solvent to clean the inside of the liquid line where the orifice tube seats. Ensure no debris or old O-ring material remains. Verify the tube seat area is smooth and undamaged.
6. 6

   Prepare the new orifice tube
   Remove the new orifice tube from packaging. Verify it matches the old tube configuration and that the screen is clean. Coat the O-rings lightly with fresh PAG oil. Add approximately 1 oz of PAG oil to the system through the liquid line opening to replace oil removed with old refrigerant.
7. 7

   Install the new orifice tube
   Insert the new orifice tube into the liquid line with the tapered end facing toward the evaporator (into the flow). Push firmly until it seats completely against the internal stop. The tube should sit flush and not protrude. Verify proper orientation before proceeding.
   ⚠Orifice tube MUST be installed in correct orientation or AC system will not function properly
8. 8

   Install new O-rings on fittings
   Remove old O-rings from both the liquid line fitting and evaporator connection. Install new O-rings in the proper grooves. Lightly coat each new O-ring with fresh PAG oil to ensure proper seal and prevent damage during installation.
   Torque spec

   AC Line Fittings20 Nm (15 lb-ft)
9. 9

   Reconnect the liquid line
   Reconnect the liquid line to the evaporator inlet. Thread the fitting by hand first to ensure proper alignment and prevent cross-threading. Once hand-tight, use a torque wrench and line wrench to tighten the AC line fitting to specification.
   Torque spec

   AC Line Fittings20 Nm (15 lb-ft)
10. 10

    Vacuum the AC system
    Connect AC manifold gauges and vacuum pump to service ports. Run vacuum pump for minimum 45 minutes to remove all air and moisture from the system. System should hold 29+ inHg vacuum. After vacuuming, close valves and watch gauges for 15 minutes - vacuum should hold steady indicating no leaks.
    ⚠Insufficient vacuum time will leave moisture in system causing corrosion and poor performance
11. 11

    Recharge the AC system
    With engine off, add refrigerant through the low-side service port using AC machine or charging equipment. Add the same amount of R-134a that was recovered, typically 1.75-2.0 lbs for this system. Do not overcharge. Verify weight on scale or use machine's automatic fill function.
12. 12

    Leak test the system
    Reconnect negative battery cable. Start engine and turn AC to MAX with fan on high. Monitor system pressures with gauges. Low side should stabilize at 25-35 psi, high side at 180-225 psi at idle with ambient temperature around 75°F. Use electronic leak detector or UV dye to verify no leaks at repaired connections.
    ℹ️Pressures will vary with ambient temperature. Refer to pressure chart for temperature compensation

Reassembly

1. Verify all AC line connections are properly torqued and leak-free
2. Confirm battery is reconnected and AC controls function properly
3. Clean any spilled refrigerant oil from engine bay components

Verification

• Run AC system for 10 minutes and verify cold air output from vents (should be 40-50°F colder than ambient)
• Check that compressor cycles properly and remains engaged under load
• Monitor system pressures remain stable within specification range
• Verify no refrigerant leaks at liquid line connection using leak detector
• Confirm AC system maintains proper cooling during test drive under various conditions
• Listen for unusual noises from compressor or expansion valve that might indicate flow restriction

More procedures for this vehicle