Mercedes-Benz

Warning/indicator lamp

Problem	Possible causes/effects andSolutions
The red coolant warning lamp lights up while the engine is running.	Possible causes: temperature sensor malfunctioning coolant level too low air supply to the engine radiator obstructed engine radiator fan faulty If a warning tone also sounds, the coolant has exceeded the temperature of 120 °C. WARNING Danger of burns when opening the bonnet If you open the engine bonnet when the engine has overheated or during a fire in the engine compartment, you could come into contact with hot gases or other escaping operating fluids. Before opening the bonnet, allow the engine to cool down. In the event of a fire in the engine compartment, keep the engine bonnet closed and call the fire service. Stop immediately in accordance with the traffic conditions and switch off the engine. Do not continue driving! Observe the messages on the multifunction display. If the coolant temperature display is at the lower end of the temperature scale: Consult a qualified specialist workshop. Otherwise: Leave the vehicle and keep a safe distance from the vehicle until the engine has cooled down. Check the coolant level. Ensure that the air supply to the engine radiator is not obstructed. Without subjecting the engine to excessive strain, continue to the nearest qualified specialist workshop. Ensure that the coolant temperature display remains below 120 °C.

Problem

Possible causes/effects andSolutions

The red coolant warning lamp lights up while the engine is running.

Possible causes:

temperature sensor malfunctioning
coolant level too low
air supply to the engine radiator obstructed
engine radiator fan faulty

If a warning tone also sounds, the coolant has exceeded the temperature of 120 °C.

WARNING Danger of burns when opening the bonnet

If you open the engine bonnet when the engine has overheated or during a fire in the engine compartment, you could come into contact with hot gases or other escaping operating fluids.

Before opening the bonnet, allow the engine to cool down.

In the event of a fire in the engine compartment, keep the engine bonnet closed and call the fire service.

Stop immediately in accordance with the traffic conditions and switch off the engine. Do not continue driving!

Observe the messages on the multifunction display.

If the coolant temperature display is at the lower end of the temperature scale:

Consult a qualified specialist workshop.

Otherwise:

Leave the vehicle and keep a safe distance from the vehicle until the engine has cooled down.

Check the coolant level.

Ensure that the air supply to the engine radiator is not obstructed.

Without subjecting the engine to excessive strain, continue to the nearest qualified specialist workshop. Ensure that the coolant temperature display remains below 120 °C.