There are some misconceptions regarding, the amount of antifreeze and water for protection in winter weather and sub-zero climates.
A mix of water and antifreeze EXCEEDING the 50\50 ratio (say 70\30) increases the freeze point protection down to -72 degrees F, but at the same time, it will reduce the cooling efficiency of the system. Plus, when the weather warms, such a 70\30 mix could cause the Engine to overheat.
A blend of 50\50 (water and antifreeze) brings protection down to -34 degrees F.
On the other hand, a 100 percent antifreeze solution (no water mixed in) has a freezing point of only 10 degrees F. above ZERO, it could turn to pure slush when outdoor temperatures drop lower than that.
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