Checking the coolant level
WARNING Risk of injury due to drive system overheating
If you open the bonnet in the event of an overheated drive system or fire in the engine compartment, the following situations may occur:
You may come into contact with hot gases.
You may come into contact with other escaping hot operating fluids.
In the event of overheating or a fire in the engine compartment, keep the bonnet closed and call the fire service.
Allow the overheated drive system to cool down if the engine must be opened.
WARNING Risk of injury due to moving parts
Components in the engine compartment can continue to run or start unexpectedly even when the drive system is switched off.
Observe the following if the bonnet must be opened:
Switch off the drive system.
Never touch the danger zone surrounding moving component parts, e.g. the rotation area of the fan.
Remove jewellery and watches.
Keep items of clothing and hair away from moving parts.
WARNING Risk of burns from hot components in the engine compartment
Certain components in the engine compartment may be very hot, e.g. drive system and cooler.
Allow the drive system to cool down and touch only the components described below.
WARNING Risk of scalding from hot coolant
If you open the cap when the drive system is at normal operating temperature, you could be scalded.
Let the drive system cool down before opening the cap.
When opening the cap, wear protective gloves and safety glasses.
Open the cap slowly to release pressure.
Park the vehicle on a level surface.
Check the coolant temperature display in the instrument cluster More.
The coolant temperature must be below 40°C.
Slowly turn cap 
anti-clockwise to release overpressure.
anti-clockwise to release overpressure. Continue turning cap anti-clockwise and remove it.
anti-clockwise and remove it. If the coolant level is below the marker bar 
, visit a qualified specialist workshop, e.g. a Mercedes-Benz Service Centre. Only have the coolant checked or refilled at a qualified specialist workshop.
, visit a qualified specialist workshop, e.g. a Mercedes-Benz Service Centre. Only have the coolant checked or refilled at a qualified specialist workshop.