This procedure adds the proper amount of PAG oil to the AC system compressor to ensure adequate lubrication and system longevity.

Warnings

Tools required

Parts

• PAG 46 oil (Ford specification) × 1 — Use OEM specification PAG 46 oil
• AC O-ring kit × 1 — Use OEM specification

Preparation

1. Park vehicle on level surface and engage parking brake
2. Allow engine to cool completely if recently operated
3. Verify refrigerant type is R-134a (should be labeled on underhood sticker)
4. Gather all required tools and materials before beginning
5. Ensure AC recovery machine is properly functioning and certified

Procedure

1. 1

   Recover refrigerant from AC system
   Connect AC recovery machine to both high and low side service ports. Follow machine instructions to completely recover all refrigerant from the system. Record the amount of oil that came out with the refrigerant (visible in recovery machine sight glass or collection bottle). This will help determine how much oil to add back.
2. 2

   Access AC compressor
   The AC compressor is located on the driver side of the engine, low and forward. Remove the engine splash shield if necessary for better access. Visually inspect compressor for any signs of leakage or damage.
3. 3

   Disconnect compressor lines
   Disconnect both the suction (low side) and discharge (high side) lines from the compressor. Use proper flare nut wrenches to avoid rounding fittings. Remove and discard old O-rings. Immediately cap all open fittings to prevent contamination and moisture entry.
4. 4

   Determine oil quantity to add
   Total system oil capacity is 8 oz (237 ml) for the 3.5L EcoBoost. If replacing compressor, add 3 oz. If adding oil due to leak repair or normal service, add the amount recovered plus 1 oz. If unknown, drain compressor completely by rotating clutch hub and inverting, then add 4 oz to the compressor.
5. 5

   Add oil to compressor
   Using the oil injector tool or syringe, add the calculated amount of fresh PAG 46 oil directly into the compressor suction port (larger fitting on compressor body). Slowly rotate the compressor clutch hub by hand 10-15 revolutions to distribute oil internally. Do not use power tools to rotate compressor.
6. 6

   Install new O-rings
   Install new O-rings on both compressor fittings. Lightly coat the new O-rings with fresh PAG 46 oil to aid installation and ensure proper sealing. Inspect mating surfaces on AC lines for damage or debris.
7. 7

   Reconnect compressor lines
   Reconnect both AC lines to the compressor. Hand-tighten first to ensure proper thread engagement, then torque to specification using a torque wrench. Do not overtighten as this can damage the fittings or compressor housing.
   Torque spec

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

   Evacuate AC system
   Connect evacuation equipment to service ports. Evacuate the system to at least 29 inches of vacuum for a minimum of 30 minutes. Monitor vacuum gauge - it should hold steady. If vacuum drops, there is a leak that must be found and repaired before proceeding.
9. 9

   Recharge AC system
   With system still under vacuum, recharge with the correct amount of R-134a refrigerant per underhood specifications (typically 1.75-2.0 lbs for this system). Add refrigerant through low side port only with engine running and AC on MAX/recirculation mode. Monitor pressures throughout charging process.
10. 10

    Verify system operation
    Start engine and turn AC to maximum cold setting. Allow system to run for 5 minutes. Check compressor engagement (clutch should cycle on and off or remain engaged). Verify cold air output from vents (should be 40-50°F at vent with 90°F+ ambient). Inspect all fittings for leaks using electronic leak detector or soap solution.

Reassembly

1. Reinstall engine splash shield if removed
2. Clear any fault codes from PCM using scan tool if AC clutch was inoperative
3. Document oil amount added and refrigerant amount for future service reference

Verification

• AC system should produce cold air (40-50°F at center vents) with ambient temperature above 70°F
• Compressor clutch should engage when AC is turned on and disengage when turned off (or remain engaged on newer variable displacement compressors)
• No refrigerant leaks detected at compressor fittings or elsewhere in system
• Low side pressure should be 25-40 psi and high side 200-250 psi at idle with AC on MAX (varies with ambient temperature)
• No unusual noises from compressor during operation

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