2008 Mercedes S-Class Owner's Manual - Page 548

Operation Engine compartment Active Body Control* (ABC*) fluid level Regular fluid level check is not required. If you notice fluid leaks or malfunction messages in the multifunction display, have an authorized Mercedes-Benz Center check the ABC-system. Coolant level The engine coolant is a mixture of water and anticorrosion/antifreeze. When checking the coolant level, the vehicle must be parked on level ground the coolant temperature must be below 158°F (70°C) Warning! Using a rag, slowly open the cap approximately 1/2 turn to relieve excess pressure. If opened immediately, scalding hot fluid and steam will be blown out under pressure. Do not spill antifreeze on hot engine parts. Antifreeze contains ethylene glycol which may burn if it comes into contact with hot engine parts. G The coolant expansion tank is located on the passenger side of the engine compartment. In order to avoid potentially serious burns: Use extreme caution when opening the hood if there are any signs of steam or coolant leaking from the cooling system, or if the coolant temperature gauge indicates that the coolant is overheated. Do not remove pressure cap on coolant reservoir if coolant temperature is above 158°F (70°C). Allow engine to cool down before removing cap. The coolant reservoir contains hot fluid and is under pressure. Example illustration from S 550 1 Cap 2 Coolant expansion tank 547