Where do you add freon to a 2011 Buick Regal?

To add freon to a 2011 Buick Regal, locate the low-pressure service port on the AC system. This port is typically found on the larger diameter aluminum line, usually near the firewall or the front of the engine compartment. Remove the cap and attach the refrigerant canister using the proper adapter, then follow the instructions on the refrigerant can for filling. Be sure to check the system's pressure to avoid overcharging.