Coolant in oil

[Bronco460fi]

Hi guys I have a 20 defender xmr. It has about 1700 miles on it had it out this weekend and it started making a noise that I thought was gears not meshing correctly then stalled. Wouldn’t start back up seemed to have a low battery so I charged it and grit to start again after work today. Still the same so I decided to drain the oil and it was full of coolant. My heart sunk. Anyone have any idea what could have caused this? And what are the odds of a complete rebuild? Thanks for your help!

[Andystoy19]

Once you tear it down you may have a better idea of what the problem is? Blown head gasket, warped head or where the leak is coming from? It may have seized because of the coolant leak into the piston area causing a hydrolock or coolant getting into the cylinder washing away the lubricant and the piston seizing to the block. You can start by removing the spark plugs and see what they look like and try the starter again to see if it is still seized if not what cylinder did the coolant get into? Have someone watch the spark plug area when you engage the starter to see which one spits coolant?? Confirm with a compression check. You may be lucky and just need to replace the head gasket??

Your water pump may have a bad seal and the antifreeze got into the oil by the shaft?? 

If the engine is seized you may be better off buying a short block once you determine what the problem is?

I hope its an easy fix.🤔