Where is the part to put freon in a Kia Optima?

To add freon to a Kia Optima, locate the low-pressure service port on the air conditioning system. This port is typically found on the larger diameter aluminum line, which runs between the compressor and the evaporator. The port is usually covered by a plastic cap, often labeled with an "L" for low pressure. Make sure the engine is off before connecting the refrigerant canister to avoid any accidents.