Coolant circuit

A coolant circuit (2) for an internal combustion engine (1), comprising:

• a coolant pump (3);
• at least one coolant line (4);
• a radiator (7);
• a coolant cavity (13) delimited in the internal combustion engine (1);
• an electronic control device (9);
• and
• an ambient temperature sensor that measures an outside ambient temperature, the ambient temperature sensor being connected to the electronic control device (9),
• wherein
• the coolant pump (3), the coolant line (4), the radiator (7) and the coolant cavity (13) are filled with a coolant (5),
• one or more sensors (8), configured to monitor the coolant concentration, are fixedly and permanently arranged in or on the coolant circuit (2),
• at least one of the one or more sensors transmits measuring results thereof to the electronic control device (9),
• the electronic control device (9) ascertains a temperature below which the coolant (5) would freeze, with reference to the measuring results of at least one of the one or more sensors (8), and compares said temperature below which the coolant (5) would freeze with a measuring result of the ambient temperature sensor (14), and
• if the comparison between said temperature below which the coolant (5) would freeze and the measuring result of the ambient temperature sensor (14) indicates that the measuring result of the ambient temperature sensor (14) is below said temperature below which the coolant (5) would freeze, the electronic control device (9) electronically prevents the internal combustion engine from starting.