AC Expansion Valve (TXV)

Replace the AC expansion valve (TXV) on a 2015-2020 Ford F-150 with 5.0L V8 engine, including refrigerant recovery, valve replacement, and system recharge.

Warnings

Tools required

Parts

• AC Expansion Valve (TXV) × 1 — Use OEM specification
• AC line O-rings (various sizes) × 1 — Use OEM specification
• PAG 46 compressor oil × 1 — Use OEM specification
• R-134a refrigerant × 1 — Approximately 1.75 lbs

Preparation

1. Verify AC complaint and confirm expansion valve failure (frost buildup on evaporator outlet, inadequate cooling, pressure readings abnormal)
2. Ensure AC recovery/recharge machine is certified and properly maintained
3. Park vehicle on level surface and set parking brake
4. Turn ignition off and remove key
5. Allow engine to cool completely (minimum 2 hours)
6. Gather all parts, tools, and refrigerant before beginning work

Procedure

1. 1

   Recover refrigerant from AC system
   Connect AC recovery machine to service ports on high and low pressure lines. Follow machine instructions to fully recover all refrigerant from the system. Record the amount recovered for comparison during recharge. Verify system pressure reads 0 PSI on manifold gauges before proceeding.
2. 2

   Remove cowl panel and wiper assembly
   Remove windshield wiper arms by lifting caps and removing retaining nuts. Remove cowl panel trim pieces on both sides. Remove plastic cowl panel by releasing clips and removing mounting screws. Set aside carefully to avoid breaking clips. This provides access to the evaporator housing.
3. 3

   Disconnect battery negative terminal
   Disconnect the negative battery cable to prevent electrical shorts and deactivate airbag system. Wait 2 minutes for capacitors to discharge before proceeding with interior work.
   ⚠Disconnecting battery will erase radio presets and may require reprogramming of certain vehicle systems.
4. 4

   Remove lower dash panel and insulation
   From passenger side, remove lower dash panel by releasing clips and removing retaining screws. Remove sound insulation padding covering the evaporator housing. Disconnect any electrical connectors for lighting or sensors in this area. Label connectors if needed for reassembly.
5. 5

   Disconnect AC lines at evaporator
   Locate the AC line connections at the evaporator inlet and outlet. Use appropriate wrench to disconnect the refrigerant line fittings. Immediately cap all open fittings with clean plugs to prevent moisture and debris entry. Remove and discard old O-rings from fittings.
   ⚠Small amount of residual refrigerant or oil may escape when lines are disconnected. Wear safety glasses and gloves.
   Torque spec

   AC Line Fittings20 Nm (15 lb-ft)
6. 6

   Access evaporator housing cover
   Locate the evaporator housing access cover on the passenger side firewall area. Remove the mounting screws securing the cover. The expansion valve is located inside this housing near the evaporator inlet.
   Torque spec

   Cover Screws14 Nm (10 lb-ft)
7. 7

   Remove expansion valve mounting
   Locate the expansion valve attached to the evaporator inlet tube. Note the orientation and position of the thermal bulb if externally mounted. Remove the mounting bracket bolts securing the expansion valve assembly. Carefully separate the valve from the evaporator inlet, noting how the sensing bulb is positioned.
   Torque spec

   Expansion Valve10 Nm (7 lb-ft)

   Mounting Bracket Bolts30 Nm (22 lb-ft)
8. 8

   Remove old expansion valve
   Carefully remove the expansion valve from the evaporator tubes. If the valve has an integral screen filter, inspect it for debris (indicates system contamination). Remove and discard old O-rings from valve seats. Clean the mating surfaces on evaporator tubes with lint-free cloth. Do not allow debris to enter evaporator.
9. 9

   Install new expansion valve O-rings
   Install new O-rings on the evaporator inlet and outlet tube connections. Coat O-rings lightly with fresh PAG 46 compressor oil (approximately 1-2 drops per O-ring). Ensure O-rings are properly seated in their grooves without twisting or pinching.
   ℹ️Use only refrigerant-compatible PAG oil. Never use petroleum-based lubricants on AC system O-rings.
10. 10

    Install new expansion valve
    Position the new expansion valve onto the evaporator tubes, ensuring proper orientation. If equipped with external thermal sensing bulb, position it in the same location as original (typically clamped to evaporator outlet tube). Hand-tighten the valve first to ensure proper thread engagement and O-ring seating.
    Torque spec

    Expansion Valve10 Nm (7 lb-ft)
11. 11

    Secure expansion valve mounting
    Install the expansion valve mounting bracket and secure with bolts. Torque mounting bracket bolts to specification. Ensure thermal sensing bulb (if external) is firmly clamped to evaporator outlet tube with good thermal contact. Verify valve body does not contact any sharp edges or vibration points.
    Torque spec

    Mounting Bracket Bolts30 Nm (22 lb-ft)
12. 12

    Reinstall evaporator housing cover
    Position the evaporator housing access cover back in place. Install and torque cover screws to specification. Ensure cover seals properly to prevent air leaks around evaporator housing.
    Torque spec

    Cover Screws14 Nm (10 lb-ft)
13. 13

    Reconnect AC lines to evaporator
    Remove protective caps from AC line fittings. Install new lubricated O-rings on AC line fittings. Add 1-2 drops of PAG 46 oil into each line connection. Connect AC lines to evaporator inlet and outlet ports. Torque AC line fittings to specification using backup wrench to prevent tube twisting.
    Torque spec

    AC Line Fittings20 Nm (15 lb-ft)
14. 14

    Evacuate AC system
    Connect vacuum pump and manifold gauges to AC system service ports. Evacuate system to deep vacuum (minimum 29 inches Hg) for at least 45 minutes. Monitor vacuum decay for 15 minutes after pump shutoff - vacuum should hold steady indicating no leaks. If vacuum drops, locate and repair leak before proceeding.
    ⚠Proper evacuation is critical to remove moisture from system. Moisture will cause expansion valve icing and system failure.
15. 15

    Recharge AC system with refrigerant
    Using AC recharge machine, add specified amount of R-134a refrigerant (typically 1.6-1.9 lbs for F-150, verify on underhood label). Add appropriate amount of PAG 46 compressor oil per manufacturer specifications (typically 2-3 oz if only expansion valve replaced). Start engine and activate AC system. Monitor pressures during charge to ensure proper system operation.
    ℹ️Overcharging or undercharging AC system will cause poor performance and potential component damage. Follow vehicle-specific refrigerant capacity exactly.

Reassembly

1. Reinstall lower dash panel and sound insulation padding, ensuring all clips engage properly
2. Reconnect any electrical connectors that were disconnected
3. Reconnect battery negative terminal
4. Reinstall cowl panel, securing all mounting screws and clips
5. Reinstall windshield wiper arms and tighten retaining nuts
6. Clear any diagnostic trouble codes that may have set during battery disconnect

Verification

• Start engine and set AC to maximum cold, maximum fan speed, recirculation mode
• Allow system to run for 5 minutes to stabilize
• Verify low side pressure reads 25-45 PSI and high side reads 150-250 PSI at idle (varies with ambient temperature)
• Check that center dash vents blow cold air (38-42°F with 95°F ambient temperature)
• Verify no frost or excessive condensation on evaporator outlet line (indicates proper expansion valve operation)
• Inspect all AC line connections for refrigerant leaks using electronic leak detector
• Listen for abnormal hissing or gurgling sounds from expansion valve area
• Test AC performance during road test under various load conditions
• Verify blower motor operates at all speeds without unusual noise
• Confirm no warning lights or AC-related diagnostic codes are present

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