my Volvo XC90 makes a hissing sound when I turn on the AC

Solution

1. Preparation

• Gather tools and parts required for repair.
• Ensure the vehicle is parked on a flat surface and the engine is turned off.

2. Recover Refrigerant

• Tools Required: Refrigerant recovery machine
• Safely connect the recovery machine to the AC service ports.
• Follow the machine’s instructions to recover any remaining refrigerant from the system.

3. Inspect and Replace Components

• Tools Required: Socket set, wrenches, torque wrench, AC manifold gauge set
• Check the AC compressor, evaporator, and condenser for damage or leaks.
• If leaks are found, replace the faulty component (e.g., compressor, O-ring, or condenser).
  • Sub-steps:
    • Disconnect the battery.
    • Remove the damaged component using the appropriate socket sizes.
    • Replace O-rings with new ones, applying refrigerant oil to ensure a proper seal.
    • Reinstall the new component and torque to manufacturer specifications.

4. Refill Refrigerant

• Tools Required: AC manifold gauge set
• Connect the manifold gauge set to the AC service ports.
• Introduce the correct type and amount of refrigerant as specified by the manufacturer.
• Monitor the system to ensure the pressures stabilize.

5. Recheck System Operation

• Start the vehicle and turn on the AC to check for the hissing noise.
• Ensure the system is cooling efficiently and the sound is eliminated.