This procedure covers the replacement of the low-side AC hose on a 2011-2014 Ford F-150 with the 3.5L EcoBoost engine, including refrigerant recovery, hose removal, installation with new O-rings, and system recharge.

Warnings

Tools required

Parts

• AC low-side hose assembly × 1 — Use OEM specification
• AC line fitting O-ring kit × 1 — Use OEM specification
• R-134a refrigerant × 1 — Check AC system capacity label under hood
• PAG 46 oil × 1 — Use OEM specification for EcoBoost AC system

Preparation

1. Park vehicle on level ground and engage parking brake
2. Turn off engine and allow to cool completely
3. Disconnect negative battery cable to prevent accidental compressor engagement
4. Locate AC system capacity label on underside of hood for refrigerant and oil specifications
5. Position recovery machine and connect to AC service ports
6. Note the amount of oil recovered during refrigerant recovery for replacement calculation
7. Photograph or document low-side hose routing before removal

Procedure

1. 1

   Recover AC refrigerant
   Connect recovery machine to high and low-side service ports. Follow recovery machine instructions to completely evacuate all refrigerant from the system. Record the amount of PAG oil recovered, as this must be replaced during reassembly. Wait until recovery machine indicates system is empty and pressures have stabilized.
2. 2

   Access low-side AC hose
   The low-side hose on the EcoBoost runs from the accumulator/drier near the firewall to the evaporator core. Remove the engine cover by pulling upward on the front clips. On 4WD models, you may need to access from underneath; raise and support the vehicle on jack stands if needed for better access to lower connection points.
3. 3

   Disconnect low-side hose at accumulator
   Locate the spring-lock coupling or threaded fitting at the accumulator/drier connection. If spring-lock type, use the appropriate size AC line disconnect tool to release the coupling. If threaded, use a backup wrench on the accumulator fitting while loosening the hose fitting to prevent component damage. Cap or plug the open accumulator port immediately to prevent moisture contamination.
4. 4

   Disconnect low-side hose at evaporator
   Access may require removing the air intake duct or moving wiring harnesses aside. Locate the connection point at the evaporator core inlet (typically near the firewall on passenger side). Use AC line disconnect tool or wrenches as appropriate for the fitting type. Use a backup wrench to prevent twisting the evaporator connection. Immediately cap the evaporator port to prevent contamination.
5. 5

   Remove hose mounting brackets
   The low-side hose is secured to the chassis or engine with one or more mounting brackets. Remove the mounting bolts and carefully note their positions for reinstallation. On the EcoBoost, these are typically located along the inner fender area. Remove the old hose assembly from the vehicle.
   Torque spec

   Mounting Bolts31 Nm (23 lb-ft)
6. 6

   Prepare new hose assembly
   Remove caps from new low-side hose. Inspect all O-rings on the new hose; even if new O-rings are included, verify they are properly seated in their grooves. Lightly coat all O-rings with fresh PAG 46 oil (approximately 1-2 drops per O-ring). Do not use petroleum-based lubricants.
7. 7

   Install new hose to evaporator
   Remove the cap from the evaporator port. Verify the port is clean and the sealing surface is undamaged. Install the new hose to the evaporator connection first, as this is typically the more difficult access point. For spring-lock fittings, push firmly until you hear/feel the connection click into place. For threaded fittings, hand-tighten first, then use backup wrench on evaporator port while torquing the hose fitting.
   ⚠Ensure new O-ring is properly positioned before connecting. A displaced O-ring will cause immediate system leak.
   Torque spec

   AC Line Fittings20 Nm (15 lb-ft)
8. 8

   Route and secure hose
   Route the new hose following the exact path of the original, ensuring it does not contact any sharp edges, hot surfaces, or moving components. The hose must have adequate clearance from the serpentine belt, turbocharger components, and exhaust manifolds. Install mounting brackets and secure with bolts.
   Torque spec

   Mounting Bolts31 Nm (23 lb-ft)
9. 9

   Connect hose to accumulator
   Remove cap from accumulator port. Install new lubricated O-ring if not already on hose end. Connect the hose to the accumulator/drier using the same method as evaporator connection. Ensure spring-lock fittings are fully engaged or torque threaded fittings to specification with backup wrench on accumulator body.
   Torque spec

   AC Line Fittings20 Nm (15 lb-ft)
10. 10

    Add replacement PAG oil
    Calculate the amount of PAG 46 oil to add based on: (1) amount recovered during refrigerant recovery, (2) amount typically held in the replaced hose (approximately 1-2 oz), and (3) any oil specified by new hose instructions. Add the calculated amount of fresh PAG 46 oil through the low-side service port using a measuring tool. Typical replacement amount is 2-3 oz for hose replacement only.
11. 11

    Vacuum test AC system
    Connect vacuum pump to AC system via manifold gauges. Evacuate system to at least 29 inches of mercury (98 kPa vacuum) and maintain for minimum 30 minutes, preferably 45 minutes. Close manifold valves and observe vacuum hold for 10 minutes. Vacuum should not drop more than 1-2 inches Hg; if it does, there is a leak that must be found and repaired.
    ⚠Inadequate vacuum time will leave moisture in the system, which can freeze at the expansion valve and damage the compressor.
12. 12

    Recharge AC system
    With vacuum still applied, connect refrigerant supply to manifold gauge set. Close vacuum pump valve and open refrigerant valve. Charge the system with the exact amount of R-134a specified on the underhood label (typically 1.75-2.10 lbs for F-150 EcoBoost). Use a refrigerant scale for accuracy. Charge through the low-side port only with engine off, or through high side with system in vacuum.
13. 13

    Test system operation
    Reconnect negative battery cable. Start engine and turn AC to MAX with fan on high. Allow system to run for 5 minutes. Monitor low-side pressure (should be 25-45 PSI depending on ambient temperature) and high-side pressure (should be 150-250 PSI). Verify compressor cycles on and off normally. Check all new connections for leaks using electronic leak detector or soap solution.

Reassembly

1. Reinstall engine cover by aligning clips and pressing firmly until seated
2. If vehicle was raised, lower from jack stands and remove wheel chocks
3. Reinstall any air intake ducts or wiring harnesses moved during access
4. Verify all tools and caps have been removed from engine bay

Verification

• Start engine and run AC system on MAX cool for 10 minutes
• Verify cold air from vents (center vent temperature should be 40-50°F below ambient)
• Check for any unusual noises from compressor or hissing sounds indicating leaks
• Visually inspect all new hose connections for signs of oil weeping or frost buildup
• Verify compressor clutch engages and disengages properly during operation
• Confirm system pressures are within specification: low side 25-45 PSI, high side 150-250 PSI at idle with 75-85°F ambient temperature
• Allow system to run through several on/off cycles to ensure proper operation
• Recheck all connection points after initial test run for any signs of leakage

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