Tractor Repair: 806 international harvester tractor, blown head gasket, connecting rod bearing

Question
QUESTION: We have an 806 international tractor and it was running fine then, it started getting hot and we think that it overheated. We shut it off and out of the smoke stack white steam was coming out. Do you have any ideas what may have happened, we are thinking the water pump but, are not too sure. If it is the water pump is it pretty easy to change?

ANSWER: White smoke or steam coming out of the exhaust usually means a blown head gasket, not a water pump.

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QUESTION: Once it cooled down we tried to start it again, the engine turned over 3-4 times then there was a light bang and now the battery won't turn the engine over. Could it be the exhaust valve, or the connecting rod bearing that seized it? We didn't turn the engine over by hand crank in the opposite direction to see if the piston was going up and hitting the head. Any suggestions as to what may have happened?

Answer
Coolant may have leaked into the cylinders causing the engine to lock up because you can't compress a liquid.  If you can turn it in the other direction by hand even a small amount, then you would know that the engine is not siezed tight.  If the engine will turn, we normally remove the injectors and then crank the engine over to see if coolant pushes out the injector holes.  This shows us which  cylinders have coolant in them, and also unlocks the engine by giving the trapped coolant a place to go.  These symptoms coincide with the steam coming out of the exhaust, indicating a blown head gasket.  The head should also be checked for cracks and warpage.