2008 Mercedes CLK-Class Owner's Manual - Page 494

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 In areas where carbon deposits may be encountered due to lack of availability of gasolines which contain these additives, Mercedes-Benz recommends the use of additives approved by us for use on Mercedes-Benz vehicles. Refer to Factory Approved Service Products pamphlet (USA only), or contact an authorized Mercedes-Benz Center 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. 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 Mercedes-Benz Limited Warranty. 493