Originally Posted by onzedge

If you have a blown head gasket, the coolant usually finds its way into the engine oil. It will make the oil look milky/frothy. This is what usually happens.

Cracked block/head is a little more difficult to ascertain.

You should get your Z to a place that can get it up on a lift and find where the leak is. Unless you have overheated your car, it is not very likely it is something different than just a leak or busted hose. A buddy with a 2009 had the upper radiator hose go bad at about 35,000 miles.