2004 Mercedes SL-Class Owner's Manual - Page 252

Operation At the gas station Warning! G i Only use premium unleaded gasoline with a minimum Posted Octane Rating of 91 (average of 96 RON/86 MON). Information on gasoline quality can normally be found on the fuel pump. For more information on gasoline, see "Premium unleaded gasoline" ( page 389) or the Factory Approved Service Pamphlet. i Leaving the engine running and the fuel cap open can cause the ? lamp to illuminate. For more information, see the "Practical hints" section ( page 285). Overfilling of the fuel tank may create pressure in the system which could cause a gas discharge. This could cause the gas to spray back out when removing the fuel pump nozzle, which could cause personal injury. Replace the fuel cap by turning it to the right. You will hear when the fuel cap is tightened. Close the fuel filler flap. You should hear the latch close shut. 251