A bit of science is needed here and might help.
If you add any imurity to any pure liquid it will elevate the boiling point and depress the freezing point. So adding water to neat anti-freeze has this effect on anti-freeze and likewise adding anti-freeze to neat water.
At around the 50 % mix of any two liquids the effect is maximised. There is some weighting towards the liquid with the lower freezing point if it also has a higher boiling point. For ethelyene glycol it somwhere around the 70-60 % point depending on complicating factors.
The thermal capacity of ethelyne glycol is also lower than water so the liquids ability to disipate heat is reduced. If you run on neat anti-freeze in the summer you could find overheating an issue.
Hope this helps !
