The temperature at which crystallization of the coolant begins; in fact — the air temperature at which frost becomes dangerous for the cooling system. The lower this value, the more the liquid is resistant to low temperatures and the better it is suitable for use in winter conditions, including in harsh climate. Note that it is worth choosing according to this indicator with a certain margin: in the characteristics, the freezing point is indicated for perfect conditions, while in fact, crystallization can begin at higher temperatures.
Relatively easy-freezing modern liquids have a minimum allowable temperature
of -40 °C and above. A value of
-41 ... -50 °C is already considered quite decent,
-51 ... -60 °C is average,
-61 ... -70 °C is not bad, and in the most frost-resistant formulations this figure can reach
-80 °C. However it is worth considering that most antifreezes with a permissible temperature below -50 °C are
concentrates, and in order to achieve these properties, they must be diluted with water in the optimal proportion (with other proportions, the temperature regime will be different). Solutions sold
ready for use usually have a freezing point above -50 °C.
Separately, it is worth touching on the difference
...between concentrates and ready-made solutions. The latter are much more convenient to use: antifreeze can be poured directly from the package, while the concentrate must first be diluted to the desired proportion with distilled water in a clean container. In addition, the properties of the diluted concentrate (including the freezing point) will directly depend on the proportion, and this dependence is non-linear and may differ in different brands of antifreeze. On the other hand, the latter can also be written as an advantage: the concentrate allows you to prepare a solution at your discretion. In addition, the frost resistance of ready-made solutions may not reach the claimed one, and a properly prepared concentrate most often has exactly the characteristics that were planned. Thus, it is considered that for personal use it is best to purchase concentrate whenever possible; ready-made solutions are popular at service stations, auto centers and other places where there is no time to mess around with concentrate dilution.
