Observe the notes on operating fluids More.
If antifreeze comes into contact with hot component parts in the engine compartment, it may ignite.
In the Mercedes-Benz Specification for Operating Fluids 320.1 at MB BeVo-ONLINE
At a qualified specialist workshop
If an inappropriate coolant is used, the engine cooling system is not sufficiently protected against overheating and corrosion at high outside temperatures.
Have the coolant regularly replaced at a qualified specialist workshop.
A minimum of 50% (antifreeze protection down to about
-37°C )A maximum of 55% (antifreeze protection down to
-45°C )