2007 Mercedes R-Class Owner's Manual - Page 372

Operation Engine compartment The coolant expansion tank is located on the passenger side of the engine compartment. Using a rag, turn cap 1 slowly approximately one half turn counterclockwise to release any excess pressure. Continue turning cap 1 counterclockwise and remove it. Coolant level 4 is correct if the level: for cold coolant: reaches the top of indicator wall 3 visible through the filling opening for warm coolant: is approximately 0.6 in (1.5 cm) higher 1 Cap 2 Coolant expansion tank 3 Indicator wall 4 Coolant level Add coolant as required. Replace and tighten cap 1. For more information on coolant, see "Coolants" ( page 543). 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. 371