2004 Mercedes CLK-Class Owner's Manual - Page 277

Operation Driving instructions Coolant temperature Warning! During severe operating conditions and stop-and-go city traffic, the coolant temperature may rise close to approx. 248°F (120°C). The engine should not be operated with the coolant temperature over 248°F (120°C). Doing so may cause serious engine damage which is not covered by the Mercedes-Benz Limited Warranty. G Driving when your engine is badly overheated can cause some fluids, which may have leaked into the engine compartment, to catch fire. You could be seriously burned. Steam from an overheated engine can cause serious burns and can occur just by opening the hood. Stay away from the engine if you see or hear steam coming from it. Turn off the engine, get out of the vehicle and do not stand near the vehicle until the engine has cooled down. 277