It's real basic but imperative if you live in the Midwest like I do or East Coast. It's getting down to -25 F Tuesday here in Illinois. Wenesday its a High of -14F and at night down to -28F. You will lose the engine in your Daily Drivers, Hotrods, & and The Race Car. Need at at least a 50/50 mix of Antifreeze. -34 F. -45F be even better.