What do the letters F and O mean on the radiator cap of a Peugeot 206?

On the radiator cap of a Peugeot 206, the letters "F" and "O" indicate the pressure rating of the cap. "F" typically stands for "Fermé" (closed), while "O" indicates "Ouvert" (open). This labeling helps users understand the pressure status of the cooling system, ensuring proper operation and preventing overheating. Always refer to the vehicle's manual for specific details regarding your model.