Replaced a bad radiator and water pump on my WD45. Filled it with water; started it up; wasn’t getting any circulation of the water, so I pulled the thermostat. It was bad... probably bad for a while from the looks of it. Put it back together without a thermostat, filled it with water, and started it up. Water level dropped so I put more water in it. Kept topping it off, not really paying attention to how much water I was putting in. After a while, the thought occurred to me that I was putting more water in than it should hold. Pulled the dipstick, and sure enough, I was circulating “chocolate milk”. As I was standing there with the dipstick in my hand, apparently enough water continued to get into the oil for the level to rise so that a little bit of the oil/water got pushed out of the dipstick hole. Needless to say, I was not a happy camper. The tractor had been running for about 10-15 minutes for that amount of water to get pushed into the oil. Pulled the valve cover and discovered an irregularly shaped hole about 1/8 of an inch in one of the freeze plugs, from rust, I assume. Some additional information: Checking the oil occasionally last year I never noticed any water in the oil. I believe there was enough antifreeze in the water so that it shouldn’t have frozen over the winter here in Western NY, but maybe I’m wrong about that. Now that I think back, it seems that the engine was running hotter than it should have been for the last few years when compared to how hot the engine gets on a recently acquired WD. My question, I guess, is: Did I find my problem in that freeze plug? Could enough water get through that small hole to get that quantity of water into the oil in that time frame? Or do I need to continue looking for a problem.