2005 Mercedes CLK-Class Owner's Manual - Page 315

Operation Engine compartment Coolant The engine coolant is a mixture of water and anticorrosion/antifreeze. To check the coolant level, the vehicle must be parked on level ground and the engine must be cool. The coolant expansion tank is located on the passenger side of the engine compartment. Warning! Using a rag, turn cap 2 slowly approximately one half turn to the left to release any excess pressure. Continue turning the cap 2 to the left and remove it. The coolant level is correct if the level for cold coolant: reaches the black top part of the reservoir for warm coolant: is approx. 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 452). 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 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 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 313