This procedure covers the removal and replacement of the low-side AC hose on a 2021-2024 Ford F-150 with 3.5L EcoBoost V6 engine, including refrigerant recovery, hose replacement, and system recharge.

Warnings

Tools required

Parts

• AC low-side hose assembly × 1 — Use OEM Ford part for 3.5L EcoBoost
• AC line O-rings × 4 — Use OEM specification
• PAG oil for AC system × 1 — PAG-46 or manufacturer specification

Fluids

• R-1234yf refrigerant

Preparation

1. Park vehicle on level surface and apply parking brake
2. Place wheel chocks behind rear wheels
3. Allow AC system to cool completely (minimum 30 minutes after engine off)
4. Raise front of vehicle and support on jack stands
5. Remove passenger-side front wheel for better access to low-side hose routing

Procedure

1. 1

   Recover AC refrigerant
   Connect AC recovery/recharge machine to service ports. Follow machine manufacturer instructions to completely recover all refrigerant from the system. Record the amount recovered for recharge purposes. Verify system is fully depressurized before proceeding.
   ⚠️System must be completely depressurized before opening any AC line connections.
2. 2

   Locate low-side AC hose connections
   The low-side AC hose on the 3.5L EcoBoost runs from the accumulator/drier (located near the passenger-side fender) to the compressor inlet. Identify both connection points. The hose may have one or more routing clips along the frame rail and inner fender.
3. 3

   Remove passenger-side fender liner clips
   Remove the plastic trim clips securing the forward portion of the inner fender liner to access the low-side hose routing. Pull the liner back carefully to expose the hose and its mounting points.
4. 4

   Disconnect low-side hose at accumulator
   Using the appropriate socket, loosen the AC line fitting at the accumulator/drier. Once loose, carefully separate the connection. Immediately cap or plug the open ports to prevent moisture and debris entry. Remove and discard the old O-rings.
   ⚠Some residual refrigerant or oil may escape when opening the connection. Ensure adequate ventilation.
   Torque spec

   AC Line Fittings20 Nm (15 lb-ft)
5. 5

   Release hose routing clips
   Locate and release all routing clips securing the low-side hose along the frame rail and engine bay. These clips may be push-type or bolt-on style. Note the exact routing for reinstallation.
6. 6

   Disconnect low-side hose at compressor
   Locate the low-side hose connection at the compressor inlet (typically on the lower portion of the compressor). Loosen and remove the AC line fitting. Separate the connection and immediately cap or plug open ports. Remove and discard the old O-rings.
   ℹ️Support the hose during removal to prevent damage to compressor threads or surrounding components.
   Torque spec

   AC Line Fittings20 Nm (15 lb-ft)
7. 7

   Remove old low-side hose
   Carefully extract the low-side hose from the engine bay, navigating it past any obstructions. Inspect the routing path and note any specific clearances or routing requirements for the new hose installation.
8. 8

   Prepare new low-side hose
   Unpack the new low-side hose assembly. Install new O-rings on both ends of the hose fittings. Lubricate the O-rings with fresh PAG oil (PAG-46 or as specified). Apply a small amount of PAG oil to the fitting threads as well to ensure proper sealing.
   ℹ️Use only AC-approved PAG oil. Do not use petroleum-based lubricants as they will damage the AC system.
9. 9

   Route and position new hose
   Route the new low-side hose through the engine bay following the exact path of the original hose. Ensure the hose does not contact sharp edges, hot exhaust components, or moving parts. Position both ends for connection without twisting or kinking the hose.
10. 10

    Connect hose to compressor
    Thread the low-side hose fitting onto the compressor inlet by hand until finger-tight. Ensure proper alignment to avoid cross-threading. Using a torque wrench, tighten the fitting to specification.
    Torque spec

    AC Line Fittings20 Nm (15 lb-ft)
11. 11

    Connect hose to accumulator
    Thread the opposite end of the low-side hose onto the accumulator/drier by hand until finger-tight. Verify proper alignment and O-ring seating. Using a torque wrench, tighten the fitting to specification.
    Torque spec

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

    Secure hose routing clips
    Install all routing clips to secure the low-side hose in its proper position. Ensure the hose follows the original routing path and maintains clearance from moving parts, hot surfaces, and sharp edges. Verify no kinks or excessive bends exist.
13. 13

    Reinstall fender liner
    Reposition the inner fender liner and secure with the original trim clips. Ensure all clips are fully seated and the liner is properly aligned.
14. 14

    Evacuate and recharge AC system
    Connect the AC recovery/recharge machine to service ports. Evacuate the system to pull a vacuum for at least 30 minutes to remove all moisture and air. Verify the system holds vacuum (no leak down). Recharge the system with R-1234yf refrigerant to the amount recovered earlier or to specification (check underhood label for capacity).
    ℹ️System must hold vacuum for at least 15 minutes without pressure rise to confirm no leaks exist.
15. 15

    Reinstall wheel and lower vehicle
    Reinstall the passenger-side front wheel and torque lug nuts to specification. Carefully lower the vehicle from jack stands and remove wheel chocks.

Reassembly

1. Double-check all AC line fittings are torqued to specification
2. Verify all routing clips are secured and hose has proper clearance
3. Ensure fender liner is properly reinstalled with all clips seated
4. Confirm wheel lug nuts are properly torqued

Verification

• Start the engine and turn AC to maximum cold with fan on high
• Allow system to run for 5-10 minutes and verify cold air output
• Check both AC line fittings for signs of refrigerant leakage (oil residue or frost)
• Verify compressor cycles on and off normally
• Use AC leak detector to check all connections if available
• Monitor system performance over next few days for any decline in cooling efficiency

More procedures for this vehicle