AC Orifice Tube

Replace the AC orifice tube, a metering device in the evaporator inlet line that can become clogged with debris and cause poor AC performance.

Warnings

Tools required

Parts

• AC orifice tube × 1 — Use OEM specification
• AC line O-ring kit × 1 — Use OEM specification
• PAG 46 refrigerant oil × 1 — Ford XT-10-QPAG 3oz

Fluids

• R-134a refrigerant

Preparation

1. Park vehicle on level surface and engage parking brake
2. Allow engine to cool completely if recently run
3. Verify AC system has refrigerant before beginning recovery process
4. Have replacement parts and O-rings ready to minimize system exposure time

Procedure

1. 1

   Recover refrigerant from AC system
   Connect AC recovery machine to low and high side service ports. Follow machine instructions to completely recover all refrigerant from the system. Verify system reaches zero pressure and record refrigerant quantity removed for recharge reference.
   ⚠️Only use certified AC recovery equipment. Never vent refrigerant to atmosphere.
2. 2

   Access liquid line at evaporator inlet
   Open hood and locate the liquid line (smaller diameter line) running from the condenser to the evaporator inlet near the firewall on passenger side. The orifice tube is located inside this line at the evaporator inlet. You may need to remove air intake components for better access on 3.5L EcoBoost.
3. 3

   Disconnect liquid line at evaporator inlet
   Use appropriate line disconnect tool to separate the liquid line fitting at the evaporator inlet. Support the line to prevent stress on connections. Immediately cap both open ends with clean plastic caps to prevent moisture and contamination entry.
   ⚠Cap open AC fittings within 15 seconds to prevent moisture contamination.
4. 4

   Remove old orifice tube
   Insert orifice tube removal tool into the evaporator inlet pipe. The tool grabs the orifice tube's outer tabs. Carefully twist and pull to extract the orifice tube. If tube breaks or is stuck, you may need to use a pick to carefully remove fragments. Ensure all pieces are removed, including the inlet screen.
   ⚠Inspect removed orifice tube for metal debris or discoloration indicating compressor failure. System may require flushing.
5. 5

   Inspect evaporator inlet
   Using a flashlight, inspect inside the evaporator inlet pipe for debris, metal shavings, or contamination. If excessive debris is present, the AC system requires professional flushing before proceeding. Clean the O-ring sealing surface on the inlet pipe with a lint-free cloth.
6. 6

   Install new orifice tube
   Remove new orifice tube from packaging only when ready to install. Note the orientation arrow on the tube body - it must point toward the evaporator (into the inlet pipe). Apply a small amount of fresh PAG oil to the O-rings on the orifice tube. Carefully insert the tube into the evaporator inlet until it seats completely and the tabs lock in place.
   ⚠Orifice tube must be installed in correct direction or AC system will not function properly.
7. 7

   Replace O-rings on liquid line
   Remove old O-rings from the liquid line fitting. Install new O-rings from kit, ensuring correct size for application. Lightly coat new O-rings with fresh PAG 46 oil before installation. Inspect fitting threads and sealing surfaces for damage.
8. 8

   Reconnect liquid line
   Remove caps from liquid line and evaporator inlet. Immediately align and connect the liquid line fitting to evaporator inlet. Hand tighten first to ensure threads engage properly, then torque to specification using a torque wrench.
   ⚠Do not overtighten AC fittings as this can damage O-rings and cause leaks.
   Torque spec

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

   Add compressor oil
   Add 1 ounce of fresh PAG 46 oil through the low side service port using an oil injector to compensate for oil lost during recovery and trapped in the old orifice tube. If significant oil was removed during recovery, add equivalent amount.
10. 10

    Evacuate AC system
    Connect vacuum pump to AC service ports. Evacuate system to 29+ inches of mercury for minimum 45 minutes. Monitor vacuum - it should hold steady. If vacuum drops, there is a leak that must be located and repaired before recharging.
    ℹ️Proper evacuation removes moisture that can damage AC components and reduce performance.
11. 11

    Recharge AC system
    Using AC machine or manifold gauge set, recharge system with R-134a refrigerant to factory specification (typically 1.75-2.0 lbs for F-150). Refer to underhood emissions label for exact capacity. Charge through low side port with engine running and AC on MAX/recirculate.
12. 12

    Reinstall removed components
    Reinstall any air intake components or covers that were removed for access. Ensure all fasteners are properly secured and no tools are left in engine bay.

Reassembly

1. Double-check all AC line connections are tight and properly torqued
2. Verify no tools or parts are left in engine compartment
3. Ensure all removed air intake components are fully reinstalled

Verification

• Start engine and turn AC to MAX cold with fan on high
• Check that compressor clutch engages and remains engaged
• Verify cold air from vents within 2-3 minutes (should reach 40-50°F)
• Inspect all AC line connections for signs of oil weeping or frost indicating leaks
• Monitor AC performance over several days to ensure proper operation
• Check AC pressures with manifold gauges: low side 25-45 PSI, high side 200-250 PSI at idle (ambient dependent)

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