This procedure guides you through properly evacuating and recharging the AC system on a 2011-2014 Ford F-150 with the 3.5L EcoBoost V6 engine to restore cooling performance.

Warnings

Tools required

Parts

• R-134a refrigerant × 1 — Use OEM specification
• PAG 46 compressor oil × 1 — Motorcraft YN-12-C
• UV dye cartridge (optional) × 1 — Use OEM specification

Preparation

1. Park vehicle on level ground and set parking brake
2. Engine should be off and cool to touch
3. Verify AC recovery/recharge machine is in good working condition with fresh filters
4. Locate low-pressure service port (larger fitting with blue/black cap on larger diameter line near accumulator on passenger side firewall)
5. Locate high-pressure service port (smaller fitting with red cap on smaller diameter line near compressor on driver side)
6. Start engine and attempt to engage AC to verify compressor clutch operation - if clutch does not engage, system may be empty or have electrical fault

Procedure

1. 1

   Connect recovery equipment to system
   Remove caps from both low-pressure and high-pressure service ports. Inspect port valve cores for damage or leaks. Connect AC recovery machine hoses to both service ports - blue hose to low-pressure port, red hose to high-pressure port. Ensure connections are secure and hand-tight.
2. 2

   Recover existing refrigerant
   Follow recovery machine manufacturer instructions to recover all refrigerant from the system. Monitor recovery process until machine indicates recovery is complete and system pressure reads 0 psi on both gauges. Most machines will automatically stop when recovery is complete. Note the amount of refrigerant recovered - significant underfill may indicate a leak. Allow recovery tank to settle for 2 minutes after recovery completes.
3. 3

   Perform vacuum test
   Start vacuum pump on recovery machine and evacuate system to at least 29 inches of mercury (98 kPa vacuum). Continue vacuum for minimum 30 minutes to remove all moisture and air from system. For 3.5L EcoBoost with dual evaporator systems (crew cab with rear AC), extend vacuum time to 45 minutes. After evacuation, close service port valves and observe vacuum gauge for 10 minutes - vacuum should hold steady indicating no leaks.
4. 4

   Verify system capacity specification
   Locate AC specification label on underside of hood or on radiator support. For 2011-2014 F-150 3.5L EcoBoost, standard capacity is 1.75 lbs (28 oz) for single evaporator or 2.25 lbs (36 oz) for dual evaporator (crew cab with rear AC). Verify exact capacity for your specific vehicle configuration. Also note required PAG oil capacity - typically 7-9 oz total system capacity.
5. 5

   Add refrigerant oil if needed
   If more than 2 oz of oil was recovered with old refrigerant, or if any components were replaced, add appropriate amount of PAG 46 oil through low-pressure port before charging. For recharge only with no component replacement, add 1-2 oz to compensate for oil trapped in recovery machine. Use only Motorcraft YN-12-C or equivalent PAG 46 oil specified for R-134a systems.
6. 6

   Charge system with refrigerant
   Set recovery machine to charge mode and input correct refrigerant amount from specification label. Machine will automatically dispense refrigerant into system. If using manual manifold gauges, charge through low-pressure port only with engine running and AC on MAX/recirculate. Add refrigerant in 4 oz increments, monitoring pressures between additions. Stop when specified weight is reached. Do not overcharge - this reduces cooling performance and can damage compressor.
7. 7

   Check static system pressures
   With engine off and system fully charged, both high and low side pressures should equalize to approximately 80-120 psi (varies with ambient temperature - higher temperatures produce higher pressure). Compare to ambient temperature pressure chart. Pressure significantly lower than expected indicates undercharge or leak. Pressure significantly higher may indicate overcharge or air/moisture contamination.
8. 8

   Verify compressor operation and running pressures
   Start engine and set AC to MAX cooling with recirculate mode on, blower on high, temperature to coldest setting. Allow system to run for 5 minutes to stabilize. Verify compressor clutch engages and remains engaged. At 75-85°F ambient temperature, typical running pressures are 25-35 psi on low side and 175-225 psi on high side. High side pressure will be higher in warmer ambient temperatures. Pressures outside normal range indicate incorrect charge, restriction, or component failure.
9. 9

   Test cooling performance
   With system running at MAX cooling, insert digital thermometer into center dash vent. After 5 minutes of operation at idle (650-750 RPM), vent temperature should be 38-48°F with ambient temperature of 75-85°F. Cooler vent temperatures are normal in cooler ambient conditions. If vent temperature is above 50°F with proper pressures, check for blend door issues or low blower speed. Rev engine to 1500 RPM briefly - vent temperature should drop 2-5°F as high side pressure increases.
10. 10

    Inspect for leaks
    With system running, use electronic leak detector to check all AC line connections, compressor shaft seal, condenser, and evaporator drain area for refrigerant leaks. Pay special attention to service port connections and any recently disturbed fittings. If UV dye was added, use UV light to inspect for fluorescent traces indicating leaks. Minor seepage at compressor shaft seal is normal on high-mileage vehicles.
11. 11

    Disconnect equipment and finalize
    Turn off AC and engine. Disconnect manifold gauges or recovery machine hoses from service ports quickly to minimize refrigerant loss (small amount of escape is normal). Immediately reinstall protective caps on both service ports finger-tight to prevent moisture and dirt entry. Wipe any oil residue from service port area. Complete work order noting amount of refrigerant and oil added.

Reassembly

1. Ensure both service port caps are installed and secure
2. Verify no tools or equipment left in engine compartment
3. Close hood and clean any refrigerant oil from paint surfaces

Verification

• Start engine and run AC on MAX cooling for 10 minutes
• Verify center dash vent temperature is 38-48°F at idle with 75-85°F ambient temperature
• Confirm compressor clutch engages and cycles normally
• Listen for unusual noises from compressor - squealing or grinding indicates compressor failure
• Check that airflow is strong from all dash vents
• Verify AC system maintains cooling during 10-15 minute test drive
• Recheck service port area for refrigerant leaks after test drive

More procedures for this vehicle