This procedure evacuates and recharges the AC system with the correct amount of R-1234yf refrigerant and lubricant to restore proper cooling performance.

Warnings

Tools required

Parts

• R-1234yf refrigerant × 1 — Use OEM specification
• PAG-46 compressor oil × 1 — Motorcraft YN-24 or equivalent
• UV leak detection dye (optional) × 1 — Use OEM specification

Preparation

1. Park vehicle on level ground and set parking brake
2. Start engine and let idle for 2-3 minutes
3. Turn AC on maximum cold, maximum fan speed, recirculation mode for 2 minutes to normalize system
4. Turn off engine and allow to cool for 5 minutes
5. Verify AC compressor clutch is not seized by manually rotating center plate
6. Locate low-pressure service port (larger cap, typically on passenger side AC line near firewall) and high-pressure port (smaller cap, typically on liquid line)
7. Clean service port areas to prevent contamination

Procedure

1. 1

   Connect recovery machine to service ports
   Remove caps from low-pressure and high-pressure service ports. Connect R-1234yf recovery machine hoses to both ports, ensuring low-pressure hose (blue) connects to low-pressure port and high-pressure hose (red) connects to high-pressure port. Verify all connections are secure and machine is set for R-1234yf refrigerant only.
2. 2

   Recover existing refrigerant
   Follow recovery machine manufacturer's instructions to evacuate all refrigerant from the system. Allow machine to run until recovery is complete and system pressure stabilizes at zero. Note the amount of refrigerant recovered - if significantly less than 1.3 lbs, there is likely a leak that must be addressed before recharging.
3. 3

   Inspect for leaks if refrigerant was low
   If recovered refrigerant was less than 80% of capacity, inspect all AC line connections, compressor shaft seal, condenser, and evaporator for signs of oil residue or damage. Use electronic leak detector or UV dye to identify leak sources. Repair any leaks before proceeding. Common leak points include compressor shaft seal, condenser front face (stone damage), and line fitting O-rings.
   ℹ️If major leak repairs are needed (compressor, condenser, evaporator), additional oil may need to be added to compensate for oil lost with leaked refrigerant.
4. 4

   Vacuum test the system
   With recovery machine or dedicated vacuum pump, pull vacuum on the system to at least 29 inches of mercury (98 kPa). Maintain vacuum for minimum 30 minutes. Monitor vacuum gauge - if vacuum does not hold steady, there is a leak that must be repaired. For best results, vacuum for 45 minutes to remove all moisture from the system.
   ⚠Moisture in the AC system will damage the compressor and reduce cooling efficiency. Adequate vacuum time is critical.
5. 5

   Verify system holds vacuum
   Close all valves on the manifold gauge set and turn off vacuum pump. Observe gauges for 10 minutes. Vacuum should not rise more than 2 inches of mercury. If vacuum does not hold, there is a leak or moisture contamination - repeat vacuum procedure or locate and repair leak.
6. 6

   Add compressor oil if needed
   Determine if compressor oil needs to be added. If only recharging with no component replacement, typically 1-2 oz of PAG-46 oil should be added to compensate for oil circulating in system. If compressor was replaced, add oil per compressor specifications (usually 6-8 oz total minus oil in new compressor). Add oil through low-pressure service port using oil injector tool before adding refrigerant.
   ℹ️Total system oil capacity is approximately 8 oz. Too much oil reduces cooling efficiency; too little causes compressor damage.
7. 7

   Add UV dye if desired
   If using UV leak detection dye for future leak diagnosis, add manufacturer-recommended amount (typically 1 oz) through the low-pressure port using dye injector. This step is optional but helpful for identifying future leaks.
8. 8

   Charge system with refrigerant
   Using recharge machine with built-in scale, add exactly 1.54 lbs (700 grams) of R-1234yf refrigerant. Charge through the low-pressure port with engine off. Monitor scale carefully - overcharging reduces efficiency and can damage compressor. Follow recharge machine instructions for automatic charging procedure.
   ⚠Accurate refrigerant quantity is critical. Overcharging by even 2 oz can cause poor cooling and high head pressure.
9. 9

   Start engine and verify compressor operation
   Start engine and turn AC to maximum cold, maximum fan speed, recirculation on. Compressor clutch should engage within 10 seconds. Verify compressor is running smoothly without excessive noise. Monitor manifold gauges: low side should read 25-45 PSI and high side should read 200-275 PSI at idle (varies with ambient temperature).
   ⚠If compressor does not engage, do not continue running engine. Check for electrical issues, pressure switch problems, or insufficient refrigerant charge.
10. 10

    Check system pressures and temperatures
    With engine at idle and AC running for 5 minutes, verify low-side pressure is 25-45 PSI and high-side pressure is 200-275 PSI (at 75-85°F ambient). At 2000 RPM, low side should be 25-40 PSI and high side 200-300 PSI. Use infrared thermometer to check center dash vent temperature should be 38-45°F at 75°F ambient temperature.
    ℹ️Pressure readings vary significantly with ambient temperature. Higher ambient temps produce higher pressures.
11. 11

    Disconnect equipment and install caps
    Turn off AC and engine. Carefully disconnect manifold gauge hoses from service ports - small amount of refrigerant will escape, this is normal. Immediately install service port caps and tighten finger-tight plus 1/4 turn to prevent moisture entry and refrigerant loss.

Reassembly

1. Ensure both service port caps are installed and tight
2. Wipe any residual oil from service port areas
3. Store all AC service equipment properly and ensure refrigerant tanks are secured

Verification

• Start engine and run AC on maximum cold for 10 minutes
• Verify center dash vent temperature is 38-45°F (use thermometer) at 75°F ambient
• Confirm compressor clutch engages and disengages normally as temperature cycles
• Listen for unusual compressor noise or belt squealing
• Verify no refrigerant odor around service ports or AC components
• Check that AC performance is consistent and cold air is delivered immediately when AC is activated
• If UV dye was added, inspect system with UV light after 24 hours of operation to verify no leaks are present

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