please excuse me an off color question

Sorry, not an orange question, but I think someone on here can probably help me. On my brother-in-law's 2294 Case IH tractor, coolant, and lots of it, showed up in the crankcase. We optimistically checked out the oil cooler first, but that was good. Next the oil pan came off, thinking probably a sleeve counter bore would be leaking. That's where the confusion started. If we didn't know better, it looked as if all 6 were leaking. How could it possibly go from none leaking to all of them leaking? The mechanic working on it cleaned and wiped down the crankcase area several times, then let it sit, and anti-freeze would show up front to back every time, as if all sleeves were leaking. Then he took one head off, pulled the sleeve that apeared to be leaking the worst, and all "O" rings looked good, no pitting or anything, nothing that looked bad. The tractor has about 8000 hrs on it, but the pistons , rings, sleeves, all looked exceptionally good. Any one have any idea which road to head down with this problem? Is there any way that a leaky head gasket could allow anti-freeze to appear in the bottom end like this? The head gasket on the front head that was removed looked good. Any help is greatly appreciated. Don't want to start a major rebuild on this engine, if we are overlooking some thing that is very simple. Thanks in advance, Darrel

if you already have the heads and the pan off...its not that far from just doing a major....sounds like it sure needs it but if you have that much anti freeze showing up Id have the block magnafluxed and the heads too.