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

Warnings

Tools required

Parts

• AC high-side hose assembly × 1 — Use OEM specification
• AC line O-rings × 4 — Use OEM specification
• PAG 46 refrigerant oil × 1 — Motorcraft YN-12-C
• R-134a refrigerant × 1 — As required by system capacity

Preparation

1. Park vehicle on level surface and engage parking brake
2. Allow engine and AC system to cool completely (minimum 1 hour)
3. Verify AC refrigerant type is R-134a (label on hood or radiator support)
4. Connect AC recovery machine and fully recover refrigerant from system following machine instructions
5. Verify system is at 0 PSI before disconnecting any lines
6. Open hood and secure in upright position

Procedure

1. 1

   Disconnect battery negative terminal
   Using a 10mm socket, loosen and remove the negative battery cable from the battery terminal. Secure cable away from battery to prevent accidental reconnection during the procedure.
2. 2

   Locate high-side AC hose
   The high-side hose runs from the AC compressor (passenger side of engine) to the condenser at the front of the vehicle. Trace the route and identify mounting brackets and connection points. On the 3.5L EcoBoost, the line runs along the passenger side of the engine bay.
3. 3

   Remove engine cover
   Lift the plastic engine cover straight up to disengage the retaining grommets. Set aside. This provides better access to the compressor area.
4. 4

   Disconnect high-side line at compressor
   Using the appropriate line wrench, loosen the fitting at the AC compressor discharge port. Support the compressor-side fitting with a backup wrench to prevent damage. Once loose, unthread by hand and remove the line. Cap or plug the compressor port immediately to prevent contamination. Discard the O-rings.
   Torque spec

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

   Remove line mounting brackets
   Using a 10mm socket, remove the bolts securing the high-side hose to its mounting brackets along the engine bay. There are typically 2-3 bracket locations. Keep hardware organized for reinstallation.
   Torque spec

   Mounting Bracket Bolts28 Nm (21 lb-ft)
6. 6

   Disconnect high-side line at condenser
   Locate the connection point at the condenser (front of vehicle, behind grille). Use a line wrench to loosen the fitting. Once loose, unthread by hand and separate the connection. Cap or plug the condenser port immediately. Remove and discard the O-rings.
7. 7

   Remove high-side hose assembly
   Carefully maneuver the high-side hose out of the engine bay, taking note of the routing path. Watch for any additional clips or guides that may secure the line. Inspect the old hose for signs of damage, oil residue, or contamination that may indicate other system issues.
8. 8

   Prepare new high-side hose
   Unpack the new high-side hose assembly. Install new O-rings on both ends of the new hose, coating them lightly with PAG 46 refrigerant oil. Add approximately 1 oz of PAG oil into the new hose to replace oil lost with the old component. Ensure caps remain on fittings until ready to install.
9. 9

   Install new high-side hose
   Route the new high-side hose through the engine bay following the same path as the original. Ensure the hose is not kinked, twisted, or making contact with sharp edges or hot components like the exhaust manifold. Verify adequate clearance from moving parts.
10. 10

    Connect hose at condenser
    Remove the cap from the condenser port and the new hose fitting. Thread the fitting onto the condenser port by hand until finger-tight, ensuring the connection is straight and the O-ring is properly seated. Using a line wrench and torque wrench, tighten to specification while holding the condenser-side fitting with a backup wrench.
    Torque spec

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

    Reinstall mounting brackets
    Secure the high-side hose to all mounting brackets along its route. Install and tighten the bracket bolts to specification using a torque wrench. Verify the hose sits properly in all clips and guides without stress or strain.
    Torque spec

    Mounting Bracket Bolts28 Nm (21 lb-ft)
12. 12

    Connect hose at compressor
    Remove the cap from the compressor discharge port and the new hose fitting. Thread the fitting onto the compressor by hand until finger-tight, ensuring proper alignment and O-ring seating. Using a line wrench and torque wrench, tighten to specification while supporting the compressor fitting with a backup wrench.
    Torque spec

    AC Line Fittings20 Nm (15 lb-ft)
13. 13

    Reinstall engine cover and reconnect battery
    Replace the engine cover by aligning the grommets and pressing down firmly until seated. Reconnect the negative battery cable and tighten the terminal nut with a 10mm socket.
14. 14

    Evacuate and recharge AC system
    Connect the AC recovery/recharge machine to the service ports. Evacuate the system to 29 inches of mercury vacuum for a minimum of 30 minutes. Monitor for vacuum hold - if vacuum drops, there is a leak that must be repaired. After successful evacuation, recharge the system with the manufacturer-specified amount of R-134a refrigerant (refer to underhood label for capacity, typically 1.8-2.1 lbs for this system).

Reassembly

1. Double-check all AC line connections are tight and properly torqued
2. Verify no tools or parts are left in engine bay
3. Confirm all mounting brackets are secured and hose routing is correct
4. Check that engine cover is fully seated on all grommets

Verification

• Start the engine and turn AC to maximum cold with fan on high
• Allow system to run for 5 minutes and verify cold air from vents
• Check high-side and low-side pressures with gauges - should read approximately 200-250 PSI (high) and 25-35 PSI (low) at idle with ambient temperature around 75°F
• Inspect all connections for signs of oil leakage or frost formation
• Use UV leak detection kit or electronic leak detector to verify no leaks at connection points
• Verify compressor clutch engages and disengages properly
• Test AC operation at various fan speeds and temperature settings
• Take vehicle for short test drive and verify AC performance under load

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