2005 Mercedes CLK-Class Owner's Manual - Page 451

Technical data Fuels, coolants, lubricants, etc. Engine oils Engine oils are specifically tested for their suitability in our engines and durability for our service intervals. Therefore, only use approved engine oils and oil filters required for vehicles with Maintenance System (U.S. vehicles) or FSS (Canada vehicles). For a listing of approved engine oils and oil filters, refer to the Factory Approved Service Products Pamphlet, or contact an authorized Mercedes-Benz Center. Using engine oils and oil filters of specification other than those expressly required for the Maintenance System (U.S. vehicles) or FSS (Canada vehicles), or changing of oil and oil filter at change intervals longer than those called for by the Maintenance System (U.S. vehicles) or FSS (Canada vehicles) will result in engine damage not covered by the Mercedes-Benz Limited Warranty. Please follow Maintenance System (U.S. vehicles) or FSS (Canada vehicles) recommendations for scheduled oil changes. Failure to do so will result in engine damage not covered by the Mercedes-Benz Limited Warranty. Engine oil additives Do not blend oil additives with engine oil. They may damage the engine. Damage or malfunctions resulting from blending oil additives are not covered by the Mercedes-Benz Limited Warranty. 449