oil in water

I believe that the crankcase ventilation system is malfunctioning.the P.C.V. valve on top of the valve cover may be plugged.There should be some kind of hose going from the valve cover (and P.C.V. valve) to the air cleaner. piston ring blowby allows combustion pressure (air) to get into the crankcase.It must find a way out . it may make its own way from the crankcase system into the cooling system.

could very well be popped head gasket, how much is in there? how often are you checking your water? a clogged PCV system will cause oil seals to leak, usually at the front or rear main, but not push oil into the water. When a head gasket blows, there's many things that go where they're not supposed to, and oil intot he water is definitly a good possibility

Yup this sounds absolutely correct to me.