2004 Mercedes C-Class Owner's Manual - Page 354

Technical data Fuels, coolants, lubricants, etc. Gasoline additives A major concern among engine manufacturers is carbon build-up caused by gasoline. Mercedes-Benz recommends only the use of quality gasoline containing additives that prevent the build up of carbon deposits. After an extended period of using fuels without such additives, carbon deposits can build up especially on the intake valves and in the combustion area, leading to engine performance problems such as: Warm-up hesitation Unstable idle Knocking/pinging Misfire Power loss Do not blend any specific fuel additives with fuel. This only results in unnecessary cost and may be harmful to engine operation. Damage or malfunctions resulting from poor fuel quality or from blending specific fuel additives are not covered by the Mercedes-Benz Limited Warranty. Flexible Fuel Vehicles Flexible Fuel Vehicles are identified by a label reading Premium gasoline or E85 only! on fuel filler flap. These vehicles are designed to operate on premium unleaded gasoline or Ethanol fuel (E85), or on any mixture of these two. Ethanol fuel (E85) is a mixture of approximately 85% Ethanol and 15% unleaded gasoline. Warning! G Ethanol fuel (E85) and its fumes are highly flammable, poisonous and burn easily. Ethanol fuel can cause serious injuries if ignited or if you come into contact with it or inhale fumes of it. Avoid inhalation of Ethanol fumes and skin contact with Ethanol. Extinguish all open flames before fueling. Never smoke or create sparks close to Ethanol. Switching fuels For best performance and driveability it is recommended to use either one or the other fuel. A refueling pattern that alternates between the two different fuels should be avoided if possible. 354