AC Expansion Valve (TXV)

This procedure replaces the AC expansion valve (TXV) on a 2015-2020 Ford F-150 with 3.5L EcoBoost engine, requiring refrigerant recovery, evaporator core access, and system recharge.

Warnings

Tools required

Parts

• AC Expansion Valve (TXV) × 1 — Use OEM specification
• AC O-ring kit × 1 — Various sizes for AC line connections
• R-134a refrigerant × 1 — Typically 1.5-2.0 lbs total system capacity
• PAG 46 compressor oil × 1 — For AC system

Preparation

1. Park vehicle on level surface and apply parking brake
2. Disconnect negative battery terminal and wait 2 minutes for airbag system to discharge
3. Verify AC system is at ambient temperature (not recently operated)
4. Identify refrigerant type using refrigerant identifier (should be R-134a)
5. Gather all replacement parts and verify correct expansion valve for 3.5L EcoBoost application

Procedure

1. 1

   Recover AC refrigerant
   Connect AC recovery machine to service ports on low and high side lines. Follow machine manufacturer instructions to fully recover all refrigerant from the system. Record amount recovered for comparison during recharge. Verify system is at 0 PSI on both high and low sides.
   ⚠️Use only approved refrigerant recovery equipment. Never vent refrigerant to atmosphere.
2. 2

   Remove lower dashboard panels
   Remove the lower dashboard trim panel on passenger side by releasing retaining clips. Remove the glove box by squeezing sides inward and lowering down. Remove any additional trim panels blocking access to the HVAC housing on passenger side footwell area.
3. 3

   Disconnect AC lines at firewall
   Working in engine bay, locate the AC liquid and suction lines at the firewall near the evaporator connections. Use line disconnect tools to separate the spring-lock couplings. Cap all open lines immediately to prevent moisture and contamination entry. Remove and discard old O-rings from line fittings.
   ⚠Residual refrigerant or oil may drip from lines. Have shop towels ready.
4. 4

   Remove evaporator cover
   Locate the evaporator housing access cover on the passenger side of the HVAC case under the dashboard. Remove screws securing the cover (typically 6-8 screws). Carefully remove the cover to expose the evaporator core and expansion valve assembly.
   Torque spec

   Cover Screws12 Nm (9 lb-ft)
5. 5

   Disconnect thermal expansion valve sensing bulb
   Locate the TXV sensing bulb attached to the evaporator outlet tube. Carefully remove any retaining clips or tape securing the bulb. Do not kink or damage the capillary tube connecting the bulb to the valve body.
6. 6

   Remove expansion valve mounting
   Identify the expansion valve mounted to the evaporator core inlet. Remove the mounting hardware securing the valve to the evaporator (typically 2 bolts or screws). Carefully note orientation and position of valve for installation of replacement.
   ℹ️Take photos of valve orientation and sensing bulb routing before removal for reference during installation.
   Torque spec

   Expansion Valve10 Nm (7 lb-ft)
7. 7

   Remove old expansion valve
   Carefully extract the old expansion valve from the evaporator inlet connection. Remove and discard all old O-rings from the valve seat connections. Inspect evaporator inlet tube for damage or debris. Clean mating surfaces with lint-free cloth.
8. 8

   Install new expansion valve
   Lubricate new O-rings with PAG 46 oil and install onto new expansion valve. Insert valve into evaporator inlet, ensuring proper orientation matches original installation. Verify valve seats fully into connection without binding or cross-threading.
9. 9

   Secure expansion valve and sensing bulb
   Install mounting hardware and torque expansion valve mounting fasteners to specification. Route sensing bulb to evaporator outlet tube in same position as original. Secure bulb with new retaining clips, ensuring good thermal contact with tube but without over-tightening.
   ⚠Do not over-tighten sensing bulb clips as this can damage the capillary tube or restrict refrigerant flow.
   Torque spec

   Expansion Valve10 Nm (7 lb-ft)
10. 10

    Reinstall evaporator cover
    Position evaporator housing cover back onto HVAC case, ensuring all alignment tabs engage properly. Install all cover screws and torque to specification in a cross-pattern to ensure even sealing.
    Torque spec

    Cover Screws12 Nm (9 lb-ft)
11. 11

    Reconnect AC lines at firewall
    Install new O-rings onto AC line fittings and lubricate with PAG 46 oil. Add 1-2 oz of fresh PAG 46 oil into suction line to replenish oil lost during service. Reconnect liquid and suction lines to evaporator connections at firewall, ensuring spring-lock couplings fully engage with audible click.
    ℹ️Verify spring-lock couplings are fully seated by attempting to pull lines apart - they should not separate.
    Torque spec

    AC Line Fittings20 Nm (15 lb-ft)
12. 12

    Evacuate AC system
    Connect vacuum pump to AC service ports. Evacuate system to 29+ inches Hg vacuum for minimum 45 minutes. Monitor for vacuum decay - system should hold vacuum indicating no leaks. If vacuum drops more than 2 inches in 10 minutes, locate and repair leak before proceeding.
13. 13

    Recharge AC system
    Using AC recharge machine, charge system with R-134a refrigerant to factory specification (verify exact amount on underhood label, typically 1.5-2.0 lbs total). Charge on low side with engine running and AC on MAX. Monitor pressures on manifold gauges to verify proper system operation.
    ⚠Do not overcharge system. Use only the amount specified on vehicle AC specification label.
14. 14

    Reinstall dashboard components
    Reinstall all dashboard trim panels, glove box, and lower covers removed during disassembly. Ensure all clips and fasteners are properly secured. Reconnect negative battery terminal.

Reassembly

1. Verify all dashboard trim panels are properly clipped and secured with no rattles
2. Confirm all AC line connections at firewall are tight and properly seated
3. Check that no tools or parts were left in engine bay or under dashboard

Verification

• Start engine and turn AC to MAX cold with fan on high
• Allow system to run for 5 minutes and verify cold air output at vents (should be 40-50°F at vent)
• Monitor AC pressures with manifold gauges: low side should be 25-45 PSI, high side 150-250 PSI at ambient temperature 70-90°F
• Listen for unusual noises from compressor or expansion valve area
• Inspect all AC line connections for refrigerant leaks using electronic leak detector or soap solution
• Verify proper system cycling - compressor should engage and disengage normally without short-cycling
• Test drive vehicle and verify AC performance remains consistent under various loads and speeds

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