2003 Mercedes CL-Class Owner's Manual - Page 340

Technical data Fuels, coolants, lubricants etc. Brake fluid During vehicle operation, the boiling point of the brake fluid is continuously reduced through the absorption of moisture from the atmosphere. Under extremely strenuous operating conditions, this moisture content can lead to the formation of bubbles in the system, thus reducing the system's efficiency. Therefore, the brake fluid must be replaced every two years, preferably in the spring. Only brake fluid approved by Mercedes-Benz is recommended. Your authorized Mercedes-Benz Center will provide you with additional information. Premium unleaded gasoline Fuel requirements Use only premium unleaded gasoline meeting ASTM standard D 439: The octane number (posted at the pump) must be min. 91 for CL 500 and CL 55 AMG and min. 93 for CL 600. It is an average of both the Research (R) octane number and the Motor (M) octane number: (R+M)/2). This is also known as the ANTI-KNOCK INDEX. Unleaded gasoline containing oxygenates such as ethanol, IPA, IBA and TBA can be used provided the ratio of any one of these oxygenates to gasoline does not exceed 10%; MTBE not to exceed 15%. ! To maintain the engine's durability and performance, premium unleaded gasoline must be used. If premium unleaded is not available and low octane fuel is used, follow these precautions: Have the fuel tank only partially filled with unleaded regular and fill up with premium unleaded as soon as possible. Avoid full throttle driving and abrupt acceleration. Do not exceed an engine speed of 3000 rpm if the vehicle is loaded with a light load such as two persons and no luggage. Do not exceed 2/3 of maximum accelerator pedal position if the vehicle is fully loaded or operating in mountainous terrain. 340