2006 Mercedes SLK-Class Owner's Manual - Page 455

Technical data Fuels, coolants, lubricants, etc. Coolant system design and coolant used determine the replacement interval. The replacement interval published in the Maintenance Booklet is only applicable if MB 325.0 anticorrosion/antifreeze solution or other Mercedes-Benz approved products of equal specification (see Factory Approved Service Products pamphlet) are used to renew the coolant concentration or bring it back up to the proper level. To provide important corrosion protection, the solution must be at least 45% anticorrosion/antifreeze (equivalent to freeze protection to approx. -22°F [-30°C]). If you use a solution that is more than 55% anticorrosion/antifreeze (freeze protection to approx. -49°F [-45°C]), the engine temperature will increase due to the lower heat transfer capability of the solution. Therefore, do not use more than this amount of anticorrosion/antifreeze. If the coolant level is low, water and MB Anticorrosion/Antifreeze should be used to bring it up to the proper level (have cooling system checked for signs of leakage). Please make sure the mixture is in accordance with label instructions. The water in the cooling system must meet minimum requirements, which are usually satisfied by normal drinking water. If you are not sure about the water quality, consult an authorized Mercedes-Benz Center. Anticorrosion/antifreeze Your vehicle contains a number of aluminum parts. The use of aluminum components in motor vehicle engines necessitates that anticorrosion/antifreeze coolant used in such engines be specifically formulated to protect the aluminum parts. (Failure to use such anticorrosion/antifreeze coolant will result in a significantly shortened service life.) Therefore, the following product is strongly recommended for use in your vehicle: Mercedes-Benz 325.0 anticorrosion/antifreeze agent. Before the start of the winter season (or once a year in hot southern regions), you should have the anticorrosion/antifreeze concentration checked. The coolant is also regularly checked each time you bring your vehicle to an authorized Mercedes-Benz Center for service. 454