Will the coolant freeze at such a low temperature?

No, according to the normal antifreeze of MINUS 20 degrees, it won't freeze.

The lower the freezing point, the better: the basic indexes of antifreeze are freezing point and boiling point. In general, the freezing point of the selected antifreeze should be lower than the local minimum temperature 10℃ to prevent sudden weather changes.

Protective effect:

First of all, it protects the components of the cooling system from corrosion.

Second, prevent scaling and reduce the heat dissipation effect of the radiator.

Third, ensure that the engine can work in the normal temperature range.