Mercedes-Benz

Warning/indicator lamp

Problem	Possible causes/effects andSolutions
The red coolant warning lamp lights up while the vehicle is on.	Possible causes: temperature sensor malfunctioning coolant level too low air supply to the radiator obstructed radiator fan faulty If a warning tone also sounds, the coolant has exceeded the temperature of 120°C. WARNING Risk of burns when opening the bonnet If you open the bonnet in the event of an overheated engine 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. Before opening the bonnet, allow the engine to cool down. In the event of a fire in the engine compartment, keep the bonnet closed and call the fire service. Stop the vehicle immediately in accordance with the traffic conditions and switch off the engine. Do not continue driving! Note the messages on the instrument cluster. If the coolant temperature display is at the lower end of the temperature scale: Consult a qualified specialist workshop. Otherwise: Exit the vehicle and keep a safe distance from it until the engine has cooled down. Check the coolant level More. Ensure that the air supply to the radiator is not obstructed. Avoiding high engine loads, drive on to the nearest qualified specialist workshop. In doing so, ensure that the coolant temperature display remains below 120°C.

Problem

Possible causes/effects andSolutions

The red coolant warning lamp lights up while the vehicle is on.

Possible causes:

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

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

WARNING Risk of burns when opening the bonnet

If you open the bonnet in the event of an overheated engine 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.

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

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

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

Note the messages on the instrument cluster.

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

Consult a qualified specialist workshop.

Otherwise:

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

Check the coolant level More.

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

Avoiding high engine loads, drive on to the nearest qualified specialist workshop. In doing so, ensure that the coolant temperature display remains below 120°C.