I'm concerned about the concentration of antifreeze to water. I don't want the coolant to freeze due to it not having enough antifreeze in the mix.
The premixed should have the protected temperature on the back of the jug. Also if you buy the non diluted and mix yourself do not use tap water but rather distilled.
another thing to consider, is adding an anode radiator cap or something similar.
an anode will keep dissimilar metals [such as an aluminum water pump and housing and an iron block] from reacting with each other, creating deposits in the cooling system that will, over time, affect the cooling ability of the entire system.
