2005 Mercedes SL-Class Owner's Manual - Page 278

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. Continue turning the cap to the left and remove it. The coolant level is correct if the level for cold coolant: is up to the upper mark on the bracing rib of the coolant expansion tank (translucent) for warm coolant: is approx. 0.6 in (1.5 cm) higher Add coolant as required. Replace and tighten cap. 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. ! SL 600 and SL 65 AMG: Only open the cap on coolant expansion tank 1. Never open the cap between the two charge-air coolers. Otherwise, the engine could be damaged. For more information, see "Coolants" ( page 435). 1 Coolant expansion tank Using a rag, turn the cap slowly approximately one half turn to the left to release any excess pressure. 276