Q: it over heat and now wont start and the engine oil looks like milkshake

Milky or milkshake-looking engine oil indicates the engine oil and engine coolant have mixed together. This can happen after a severe overheating of the engine. This mixing can happen from either the head gasket cracking, or the cylinder head itself cracking.If a crack or break in either happen between a coolant and oil passage, then the oil and coolant will mix. Also, cylinder compression can be effected if the overheat was severe enough to crack the head, or not only crack the gasket between oil and coolant passages, but around a cylinder bore as well. Lack of compression can be the reason for the crank but no start condition. The cylinder head should be removed and sent to a machine shop for inspection before further repairs are attempted. Generally, a cracked cylinder head is non-repairable and has to be replaced.