Oil and water DO mix in a WD45

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.

That hole is probably it. Never hurts to drop the pan and see if the sleeve o-rings are leaking as well.
AaronSEIA

Corrosion surely is your enemy and attention needs to be made to when coolant should be replaced and distilled water is used in place of well water. Also, suitable coolant conditioners need to be utilized. Lastly, I live in Western NY and I set my coolant mixture so it is good to minus 30 degrees F. Many a winter it does get 5 to 10 degrees colder on a given day/ evening than what the weather forecasters predict.

Does not take a very big hole to move a lot of water fast plus the engine being warm and the radiator system have some pressure to it and all

If you"re good for -30, it isn"t about to freeze solid at -40. Just turns to slush first.

And check the bearings! That much water could easily have wiped them out. Leon

Thanks to all of you for your help!