i searched and didnt see anyone really touch upon this issue, which i think is a testament to the minor significance of the subject. maybe im just splitting hairs here, but i always used a 50/50 dH2O : coolant mixture. however, according to howstuffwroks, a 70/30 coolant : dH2O seems to employ a broader temperature range, which to me seems more desirable, especially here in MA. so how are the rest of you preparing your coolant mixtures???
50/50 v. 70/30