2008 Mercedes CLK-Class Owner's Manual - Page 329

Operation Engine compartment Coolant 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, turn cap 2 slowly approximately one half turn counterclockwise to release any excess pressure. Continue turning the cap 2 counterclockwise and remove it. The coolant level is correct if the level for cold coolant: reaches the marking (plastic bridge) inside the reservoir for warm coolant: is approximately 0.6 in (1.5 cm) higher Add coolant as required. Replace and tighten cap 2. More information on coolant can be found in the "Technical data" section ( page 494). 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 indicator indicates that the coolant is overheated. Do not remove pressure cap on coolant reservoir if the coolant temperature is above 158°F (70°C). Allow the coolant to cool down before removing cap. The coolant reservoir contains hot fluid and is under pressure. 1 Coolant expansion tank 2 Cap 328