2009 Mercedes SLR McLaren Owner's Manual - Page 255

Operation Engine compartment Coolant The engine coolant is a mixture of water and anticorrosion/antifreeze. When checking coolant level, the vehicle must be parked on level ground the coolant temperature must be below 158°F (70°C) Warning! Continue turning the cap to the left and remove it. The coolant level is correct if the level for cold coolant: reaches the upper mark on the bracing rib of the expansion tank (arrow) for warm coolant: is approximately 0.4 in (1 cm) higher Add coolant as required. Replace and tighten cap. For more information, see "Coolants" ( page 398). 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 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. 1 Expansion tank Using a rag, turn cap slowly approximately one half turn to the left to release any excess pressure. 255