How is it running - any roughness or smoke from the tail pipe? Have you checked the coolant overflow tank? Wondering what the level is right now, what the stuff looks like, and if any of it looks frozen or slushy. If someone filled it with water, seems like it would have frozen before this current cold snap. But if it's not water in the tank, then one would think any coolant sold these days should protect to at least -35 or so. But I agree that lots of water in the oil doesn't sound good. Hope this turns out to be an easy, low cost fix for you!