2011 Mercedes E-Class Owner's Manual - Page 338

336 Service products and capacities Direct skin contact with fuels and the inhalation of fuel vapors are damaging to your health. Premium-grade unleaded gasoline ! To ensure the longevity and full performance of the engine, only premiumgrade unleaded gasoline must be used. If premium-grade unleaded gasoline is unavailable and regular gasoline is used, observe the following precautions: Ronly fill the fuel tank to half full with regular unleaded gasoline and add the rest as soon as possible with premiumgrade unleaded gasoline. Rdo not drive at the maximum speed. Ravoid sudden acceleration. Rwhen the vehicle is carrying a light cargo, e.g. two passengers without luggage, do not allow the engine to rev above 3000 rpm. Rwhen the vehicle is fully loaded or being operated in mountainous terrain, do not depress the accelerator pedal further than 2/3 of the pedal travel. Fuel requirements Use only premium-grade unleaded gasoline. The octane number should be at least 91. Details can be found on the gas pump. The octane number is the average value of the Research Octane Number (RON) and Motor Octane Number (MON): (RON + MON) / 2, also known as knock resistance. Reformulated Gasoline (RFG) and/or unleaded gasoline with additives can be used if the concentration of the additives in the fuel does not exceed 10%, e.g.: REthanol RTAME RETBE RIPA RTBA For MTBE, the concentration should not exceed 15%. The concentration of methanol in gasoline including other additives must not exceed 3%. Using mixtures of methanol and ethanol is not permitted. Gasohol, a mixture of 10% ethanol and 90% unleaded gasoline can be used. All of these mix fuels must fulfill the fuel requirements, e.g.: Rknock resistance point Rvapor pressure Rboiling Additives in gasoline One of the major problems in engine design is the creation of carbon deposits during the process of burning fuel. Mercedes-Benz recommends that you use fuel brands that have the additives which prevent the build up of carbon deposits. If you use fuels without these additives for a longer period of time, there may be a build up of carbon deposits, especially on the inlet valves and in the combustion chamber. This could lead to engine running problems, e.g.: Rwarm-up Runstable Technical data hesitation idle Rknocking/pinging Rmisfire Rpower loss In areas where carbon deposits may be encountered due to lack of availability of gasoline which contains these additives, Mercedes-Benz recommends the use of additives approved for use in Mercedes-Benz vehicles. Consult an authorized Mercedes-Benz Center or visit http://www.mbusa.com (USA only) to view a list of approved products. Observe the instructions for use on the product label. Do not mix other fuel additives with fuel. This causes unnecessary costs and could damage the engine.