2009 Mercedes CLS-Class Owner's Manual - Page 349

Technical data Fuels, coolants, lubricants etc. RDo not exceed an engine speed of 3 000 rpm if the vehicle is loaded with a light load such as two persons and no luggage. not exceed 2/3 of maximum accelerator pedal position if the vehicle is fully loaded or operating in mountainous terrain. These blends must also meet all other fuel requirements, such as resistance to spark knock, boiling range, vapor pressure, etc. RDo 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: RWarm-up RUnstable Contact an authorized Mercedes-Benz Center or visit www.mbusa.com (USA only) for a listing of approved product(s). Follow directions on product label. Do not blend other fuel additives with fuel. This only results in unnecessary cost and may be harmful to the engine operation. Fuel requirements Only use premium unleaded gasoline. The octane number (posted at the pump) must be 91 min. It is an average of both the Research Octane Number (RON) and the Motor Octane Number (MON): (RON+MON)/2. This is also known as the ANTI-KNOCK INDEX. Reformulated gasolines (RFG) and/or unleaded gasoline containing oxygenates such as ethanol, TAME, ETBE, IPA, IBA, and TBA can be used provided the ratio of any one of these oxygenates to gasoline does not exceed 10%; MTBE must not exceed 15%. The ratio of methanol to gasoline must not exceed 3% plus additional cosolvents. Using mixtures of ethanol and methanol is not allowed. Gasohol, which contains 10% ethanol and 90% unleaded gasoline, can be used. ! Damage or malfunction resulting from poor fuel quality or from blending additional fuel additives other than those tested and approved by us for use on Mercedes-Benz vehicles are not covered by the MercedesBenz Limited Warranty or by any pre-owned or Extended Limited warranties. Coolants The engine coolant is a mixture of water and anticorrosion/antifreeze, which provides: RCorrosion RFreeze hesitation idle RKnocking/pinging RMisfire RPower protection loss protection 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 by us for use on Mercedes-Benz vehicles. RBoiling protection (by increasing the boiling point) The cooling system was filled at the factory with a coolant providing freeze protection to approximately -35‡ (-37†) and corrosion protection. Z 347