Well guys, it was a blown head gasket but that is the least of my problems. Piston No. 2 came apart as shown in the attached photo. The sleeve was scratched, imagine that, but not enough to get into the block. I know I'm in for a complete overhaul but I would like your opinion on what caused this. The tractor has ran great for the 3 years I have had it. It didn't smoke or burn oil. There weren't even any leaks. The tempature gauge broke about 2 week ago and I had a new one for replacement but didn't get around to replacing it "dumb a**". Could the head gasket have blown causing water to be sucked into this cylinder and causing the piston to disintergrate? It didn't seem like the tractor ran hot although without a gauge I couldn't be positive. When I tried to drain the water from the block by the pet cock, there was no water. When I pulled the oil drain plug, there was water in the oil. I know I have to do the overhaul but would like your opinion on what caused this damage.