This procedure evacuates the existing refrigerant from the AC system, checks for leaks, and recharges the system with the correct amount of R-134a refrigerant and PAG oil for the 2015-2020 Ford F-150 3.5L EcoBoost.

Warnings

Tools required

Parts

• R-134a refrigerant × 1 — Use OEM specification
• PAG 46 oil for AC system × 1 — Motorcraft YN-19 or equivalent
• AC service port caps × 2 — Replace if damaged

Fluids

• R-134a Refrigerant

Preparation

1. Park vehicle on level surface and set parking brake
2. Ensure engine is off and cool to the touch
3. Locate the low-side service port (larger diameter, on accumulator/drier near firewall) and high-side service port (smaller diameter, on AC line near compressor)
4. Remove caps from both AC service ports and inspect for damage or debris
5. Verify AC recovery/recharge machine has empty recovery tank and is properly calibrated

Procedure

1. 1

   Connect recovery equipment
   Connect the AC manifold gauge set or recovery machine to both the low-side (blue) and high-side (red) service ports. Ensure connections are tight to prevent refrigerant loss. Do not open valves yet.
2. 2

   Recover existing refrigerant
   Follow the recovery machine manufacturer's instructions to recover all refrigerant from the system. This typically takes 10-15 minutes. The machine will indicate when recovery is complete and the system is at atmospheric pressure or below. Record the amount of refrigerant and oil removed for reference.
3. 3

   Perform vacuum test
   With the recovery complete, use the machine's vacuum pump to pull a vacuum on the system to at least 29 inches of mercury (inHg). Continue vacuuming for a minimum of 30 minutes to remove all moisture and air from the system. This is critical for proper AC performance.
4. 4

   Verify system holds vacuum
   Close off the vacuum pump and monitor the gauge for 10-15 minutes. The vacuum reading should remain stable (not rise more than 1-2 inHg). If vacuum rises significantly, there is a leak in the system that must be repaired before proceeding. If vacuum holds, proceed to recharge.
5. 5

   Add PAG oil if needed
   Calculate the amount of PAG 46 oil to add based on what was removed during recovery. If oil amount is unknown or if components were replaced, add 3 oz of PAG 46 oil through the low-side service port using the recharge machine's oil injection feature. The 3.5L EcoBoost system holds approximately 7 oz total.
6. 6

   Charge with refrigerant
   Charge the system with R-134a refrigerant. The 2015-2020 F-150 3.5L EcoBoost requires 1.94 lbs (31 oz) of R-134a. Use the recovery/recharge machine to add refrigerant through the low-side port. Do not exceed the specified capacity. The machine should automatically stop at the programmed amount.
7. 7

   Start engine and verify system operation
   Start the engine and turn the AC to maximum cool with the blower on high. Allow the system to run for 2-3 minutes. Monitor the gauge pressures: low-side should be approximately 25-45 psi and high-side should be approximately 150-250 psi at ambient temperature of 70-90°F. Pressures will vary with ambient temperature.
8. 8

   Check vent temperature
   Insert a thermometer into the center dash vent with AC running at maximum. Vent temperature should be 35-45°F with ambient temperature around 70-80°F. If temperature is not within range, verify refrigerant charge and check for restrictions or compressor issues.
9. 9

   Perform leak check
   With the system running, use an electronic leak detector to check all AC line connections, compressor seals, condenser, and evaporator drain area for leaks. Pay special attention to service port connections and any recently disturbed fittings. If UV dye was added, use UV light to inspect for leaks.
10. 10

    Disconnect equipment and install caps
    Turn off the AC and engine. Carefully disconnect the manifold gauges from the service ports, working quickly to minimize refrigerant loss (small amount of loss is normal). Immediately install service port caps and tighten finger-tight plus 1/4 turn to seal the ports.

Reassembly

1. Ensure both service port caps are installed and secure to prevent contamination and refrigerant loss
2. Verify no tools or equipment are left in the engine bay
3. Record the refrigerant and oil amounts added for future service reference

Verification

• Start the engine and run the AC on maximum cool for 5 minutes, confirming cold air from all vents
• Verify vent temperature is 35-45°F at idle and remains consistent
• Check that the compressor clutch engages and disengages normally without unusual noise
• Monitor gauge pressures if still connected: low-side 25-45 psi, high-side 150-250 psi (varies with ambient temperature)
• Confirm no refrigerant odor or visible oil residue around service ports or AC components
• Test AC performance at various blower speeds and temperature settings to ensure proper operation

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