2003 Mercedes E-Class Owner's Manual - Page 370

Technical data Fuels, coolants, lubricants etc. Damage or malfunctions resulting from poor fuel quality or from blending specific fuel additives are not covered by the Mercedes-Benz Limited Warranty. Coolants The engine coolant is a mixture of water and anticorrosion/antifreeze, which provides: Corrosion protection Freeze protection Boiling protection (by increasing the boiling point) The cooling system was filled at the factory with a coolant providing freeze protection to approximately -22°F (-30°C) and corrosion protection. If the antifreeze mixture is effective to -22°F (-30°C), the boiling point of the coolant in the pressurized cooling system is reached at approximately 266°F (130°C). The coolant solution must be used year-round to provide the necessary corrosion protection and increase boil-over protection. You should have it replaced every 15 years or 150 000 miles (250 000 km), whichever comes first. Coolant system design and coolant used stipulate the replacement interval. The above replacement interval 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. 370