This procedure evacuates, vacuum tests, and recharges the A/C system with R-134a refrigerant to restore proper cooling performance.

Warnings

Tools required

Parts

• R-134a refrigerant × 1 — 400-450g total capacity
• PAG 46 compressor oil × 1 — ND-OIL 11 or equivalent PAG 46
• A/C system UV dye (optional) × 1 — Use OEM specification

Preparation

1. Park vehicle on level surface and engage parking brake
2. Ensure engine is off and cool to the touch
3. Verify A/C compressor clutch engages when A/C is turned on (listen for click and observe clutch). If clutch does not engage, system may be completely empty and require leak diagnosis first
4. Locate low-pressure service port (larger diameter, blue or black cap) on suction line near firewall on passenger side
5. Locate high-pressure service port (smaller diameter, red cap) on liquid line near condenser
6. Clean area around both service ports to prevent contamination

Procedure

1. 1

   Connect recovery/recharge machine to vehicle
   Remove caps from low-pressure and high-pressure service ports. Connect the blue hose from the manifold gauges to the low-pressure port and the red hose to the high-pressure port. Ensure connections are secure and hand-tightened. Do not open valves yet.
2. 2

   Recover existing refrigerant
   Follow recovery machine instructions to safely recover any remaining refrigerant from the system. Start the recovery process and allow machine to run until both gauges read zero or vacuum (typically 5-10 minutes). Record the amount of refrigerant recovered - if significantly less than 400g, a leak is present and must be repaired before proceeding.
3. 3

   Perform vacuum test
   With recovery complete, switch machine to vacuum mode or connect vacuum pump. Evacuate system to at least 29 inches Hg (98 kPa vacuum) and maintain for minimum 30 minutes. This removes moisture and air from the system. Monitor vacuum gauge - if vacuum does not hold steady for 10 minutes after pump stops, system has a leak that must be located and repaired.
4. 4

   Add compressor oil if needed
   If more than 60ml of oil was recovered with old refrigerant, or if system was opened for component replacement, add PAG 46 oil through the low-pressure port using oil injector. For routine recharge with no component replacement, add 30-40ml. For compressor replacement, refer to compressor oil capacity specifications.
5. 5

   Charge system with R-134a refrigerant
   Connect refrigerant supply to recharge machine. With engine off, add refrigerant through low-pressure port only until system reaches approximately 200g. Start engine and set A/C to MAX with fan on high and recirculation on. Continue charging through low-pressure side only while engine runs until total charge reaches 400-450g as specified on underhood label. Monitor high-side pressure - should not exceed 2.0 MPa (290 psi) during charging.
6. 6

   Verify system pressures
   With engine at idle (approximately 800 RPM), A/C on MAX, fan on high, and ambient temperature around 25°C (77°F), verify static pressures: Low side should read 0.20-0.25 MPa (30-36 psi), high side should read 1.4-1.6 MPa (200-230 psi). Pressures will vary with ambient temperature - higher temperatures produce higher pressures. Compressor clutch should cycle on and off regularly.
7. 7

   Check for leaks
   With system charged and running, use electronic leak detector or UV light (if dye was added) to inspect all connections, service ports, compressor shaft seal, condenser, evaporator drain, and line fittings. Pay special attention to service port caps and any previously repaired areas. If leaks are detected, recover refrigerant, repair leak, and repeat procedure.
8. 8

   Disconnect equipment and secure service ports
   Turn off engine and A/C system. Close all valves on manifold gauge set. Carefully disconnect hoses from service ports - small amount of refrigerant may escape. Immediately reinstall service port caps and tighten securely by hand to prevent moisture intrusion and refrigerant loss.

Reassembly

1. Ensure both service port caps are installed and hand-tight
2. Verify no tools or equipment are left in engine bay
3. Store manifold gauges and recovery machine properly according to manufacturer instructions

Verification

• Start engine and turn A/C to MAX with fan on high setting
• Allow system to run for 5 minutes to stabilize
• Measure center vent temperature with infrared thermometer - should be 4-10°C (40-50°F) cooler than ambient temperature, typically 5-8°C (41-46°F) at idle with 25°C ambient
• Verify compressor clutch engages and disengages normally (cycling is normal behavior)
• Listen for unusual noises from compressor - should run smoothly without squealing or grinding
• Check that both A/C lines show temperature differential - suction line (low pressure) should be cold to touch, liquid line (high pressure) should be warm
• Test A/C performance during short test drive to confirm adequate cooling under load

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