I think what would help is if I could find a way to tell if this oil has just water, or water and antifreeze in it, although I think it must be both or the water would seperate out of the oil. The cooling system has antifreeze, however weak it is, in it now. I'm thinking since I need to change the water pump to test anything, maybe flushing it out and filling with plain water, filling the oil and going from there might give me some answers.

I think if it's cracked, it will be from freezing, in this climate it gets as cold as 20 below at times in the winter.

As for engines, between the yards I go to and my one buddy I could probably check over 50 of them, priced from free to $75 or so, but finding one that turns over and doesn't have the same problems as this will be a crap shoot.