What's the 2012 bmw 328i coolant type?

You're going to want to use ZerexBlue 50/50 Coolant/Antifreeze in your 2012 BMW 328I. You can substitute this one for any that uses inorganic acid technology (IAT), but don't mix with other "colors" (ie, OAT or HOATs). Doing so can result in eventual corrosion of your radiator as well as other parts of your heat dispersal system, which can result in your engine overheating and turning into a worthless hunk of melted metal. You'll know it's time to change the coolant if your heater stops working, or if you can smell a lot of burning odor come from under the hood, or, of course, if you see it leaking out on the ground: A flush should identify where it's leaking, in the last case.