Why did the oil from the oil bath filter come thru the air intake of our tractor?

My Dad's Ford 3000 diesel farm tractor has a lot of wear and tear on it and plenty of blow by. We've had trouble starting it recently and we believe it's because it's lost a lot of it's compression. We went to pull it off today with our other tractor and when he popped the clutch and had it turning the engine oil from the filter system came gushing out of the air intake all over the hood. We can't figure out what would have caused this or why the oil came up the air intake tube. ThanksWhy did the oil from the oil bath filter come thru the air intake of our tractor?
It sounds like you have a blown head gasket. I had exactly the same thing happen to me. When the oil pressure came up it pushed the oil into the cylinder then the piston pumped it up through the intake. It would also explain what you thought was blow by. A cylinder pressure test will have the same readings as blow by so its easy to miss it.Why did the oil from the oil bath filter come thru the air intake of our tractor?
Sounds like it's about ready to crap out for good.