2006 Mercedes CLS-Class Owner's Manual - Page 299

Operation Engine compartment The coolant expansion tank is located on the driver's side of the engine compartment. Continue turning the cap counterclockwise and remove it. The coolant level is correct if the level for cold coolant: reaches the top of the mark (plastic bridge) visible through the filling opening for warm coolant: is approximately 0.6 in (1.5 cm) higher Add coolant as required. Replace and tighten cap. Coolant expansion tank Warning! G In order to avoid any possibly 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. 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. For more information on coolant, see the "Technical data" section ( page 466). Using a rag, turn the cap slowly approximately one half turn counterclockwise to release any excess pressure. 298