AC Orifice Tube

This procedure covers the replacement of the AC orifice tube, which filters and meters refrigerant flow in the air conditioning system of 2014-2019 Toyota Corolla vehicles with the 1.8L I4 engine.

Warnings

Tools required

Parts

• AC orifice tube × 1 — Use OEM Toyota specification
• AC line O-rings × 1 — Use OEM specification - multiple sizes
• R-134a refrigerant × 1 — As needed per system capacity
• PAG oil (ND-11 or equivalent) × 1 — Use OEM specification

Preparation

1. Verify AC system has not been recently operated to reduce pressure and temperature
2. Park vehicle on level ground and engage parking brake
3. Ensure AC recovery machine is functioning properly and has adequate storage capacity
4. Gather all new parts and verify correct orifice tube color code for your specific model year
5. Keep new O-rings sealed until installation to prevent contamination

Procedure

1. 1

   Recover refrigerant from AC system
   Connect AC recovery machine to both high and low side service ports. Follow machine manufacturer instructions to fully recover all refrigerant from the system. Record the amount recovered for recharge reference. Wait until system shows 0 PSI on both gauges before proceeding.
   ⚠️Ensure recovery machine is properly connected and system is fully evacuated before opening any lines.
2. 2

   Access the liquid line at condenser outlet
   Open the hood and locate the liquid line connection at the condenser outlet on the passenger side of the vehicle. This is where the orifice tube is housed. Remove any plastic covers or clips securing the line. The orifice tube is located inside the line fitting nearest to the condenser.
3. 3

   Disconnect liquid line fitting
   Using the appropriate line disconnect tool, carefully separate the liquid line fitting at the condenser outlet. Immediately cap both open ends with clean plugs to prevent moisture and debris entry. Some residual oil may drain out - this is normal. Use clean towels to catch any spillage.
   ⚠Even after recovery, some refrigerant may remain in the system. Work in a well-ventilated area.
4. 4

   Extract the old orifice tube
   Using needle nose pliers, carefully grip the orifice tube by its outer edge (not the screen) and pull straight out from the line. Do not twist or use excessive force as this can push the tube further in or damage it. If stuck, use a specialized orifice tube removal tool. Inspect the old tube for debris, metal particles, or discoloration which indicates compressor damage.
   ⚠If the screen is heavily clogged or contains metal particles, the compressor may be failing and should be inspected before proceeding.
5. 5

   Clean line and inspect for debris
   With the orifice tube removed, inspect inside the liquid line for any debris or contamination. Use a clean lint-free towel to wipe the interior if needed. Check that the sealing surface on both the line and condenser fitting are clean and undamaged. Replace the line if the internal surface is scored or damaged.
6. 6

   Install new orifice tube
   Remove the new orifice tube from its packaging. Note the orientation - the tube has a specific inlet and outlet direction indicated by an arrow or shorter screen side (inlet points toward condenser). Add 1-2 drops of fresh PAG oil to the O-rings on the tube. Insert the new tube straight into the liquid line until it seats against the internal stop. Push firmly but do not force.
   ⚠Installing the orifice tube backwards will cause AC system malfunction. Verify correct orientation before insertion.
7. 7

   Replace O-rings on line fittings
   Remove and discard the old O-rings from both sides of the disconnected fitting. Install new O-rings of the correct size from your O-ring kit. Lubricate each new O-ring with fresh PAG oil (ND-11 specification) before installation. Ensure O-rings are seated properly in their grooves without twisting or pinching.
8. 8

   Reconnect liquid line fitting
   Remove caps from both line ends. Align the liquid line fitting carefully and push together by hand until seated. Install the fitting fastener and torque to specification using a torque wrench. Ensure the connection is straight and not cross-threaded.
   ℹ️Do not overtighten AC fittings as this can damage the soft aluminum threads.
   Torque spec

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

   Evacuate the AC system
   Connect the AC machine to service ports. Run a vacuum on the system for at minimum 30 minutes, ideally 45 minutes. The system should hold a vacuum of at least 29 inches Hg. After vacuum time, close valves and monitor for 10 minutes - vacuum should not drop more than 1-2 inches Hg, indicating no leaks.
   ⚠If the system will not hold vacuum, there is a leak that must be found and repaired before recharging.
10. 10

    Recharge AC system
    With the system under vacuum, recharge with the amount of R-134a refrigerant specified on the underhood label (typically 380-420 grams for this model). Add the appropriate amount of PAG oil if significant oil was lost during the repair (typically 20-30ml for orifice tube replacement). Follow your AC machine's recharge procedure. Do not overcharge the system.

Reassembly

1. Reinstall any plastic covers or heat shields that were removed for access
2. Verify all AC line connections are secure and properly torqued
3. Check that no tools or parts were left in the engine compartment

Verification

• Start the engine and turn AC to maximum cold and high fan speed
• Allow system to run for 5 minutes and verify both high and low side pressures are within normal range (low side 25-35 PSI, high side 200-250 PSI at idle with 80°F ambient)
• Check that center dash vents blow cold air (38-42°F at maximum cool)
• Inspect all AC line connections for oil residue or frost indicating leaks
• Verify compressor clutch engages and disengages normally when AC is cycled on/off
• Listen for abnormal noises from the compressor or system components

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