Neighbor has a Kubota mx500 with oil in water. Has less than 500 hours. Not oil cooler (we bypassed it). Anything available to put in oil to stop the leak (like a block sealer, blue devil doesn't make anything)? How can one tell exactly where it is leaking? Does a bad injector pump seal allow oil to reach water?? Thanks much.
Have you checked the oil/drained the oil out of the oil pan? Water in it? I think I would drain the oil out, and then get a pressure test kit, pressurize the cooling system for a hour or two, and see if there is any water in the oil pan after you drain the oil. P.S. The more I think about it, any oil getting in the coolant would have to overcome the pressure of the cooling system to enter. What pressure cap do they run now, 12-15lbs? That would mean the oil would have to be at a pressure higher than 12-15lbs to enter the cooling system, unless it enters when the tractor is off and cooled down.
Never underestimate the power of Google. http://www.orangetractortalks.com/2008/12/found-oil-in-your-coolant/
You won't beat that explanation. With pictures no less. I will argue with "frost plugs", they are put in engines to seal the holes where the sand is knocked out of the casting, and for that reason ONLY. AFAIK
I've seen frost plugs pushed out by ice before - but more often I've seen cracked blocks with the freeze plugs still intact. Even if those plugs did push out under the valve cover or behind the gear case, I would think there would be more water in the oil than oil in the water. They don't strike me as a place of high oil pressure - but maybe high enough?
Very late update. It was the head. The head was checked by two different reputable(???) shops. They both said the head was good. Took a 40 year mechanic who had extensive experience with head shops to tell us what diagnostics we needed to do, which included tapping and plugging the oil port going to the head and pressurizing it. Put the head in water and pressurized and it clearly showed a bad head. ' Put a new head on and it runs fine. Thanks for all the help. The machine shops (head shops) really threw us off and could have easily cost us a $5000.00 engine replacement job.
Was it a factory defect in the casting or did something cause a crack or what?
Not sure, but it was cracked badly.