Update-

Thanks for all the tips so far gents! I replaced the oil cooler (just because it was relatively inexpensive and easy) and added stop leak. I ended up using the Bars Leaks liquid copper stuff. I ran it for about 45 minutes and checked oil and water levels several times, oil level didn't rise and coolant level didn't drop. A couple days later I worked the machine for the first time since purchasing it. I pushed up and turned over an old brush pile and everything was fine. A new issue has cropped up though, 2nd and 3rd gear seem to slip. When I test drove it before purchasing it seemed to work fine, but that was all on hard level ground. I want to do some searching around the forums for some troubleshooting tips before I ask questions that may have already been answered on here. Do any other machines use the same transmission as the 951C-86J that I could use for keyword searches so I can find the most info? The so called service manual I have is pretty worthless and may have to invest in a better one.

I also have had a problem with my 86J 951C..............................it was leaking coolant into the crankcase after setting for a while. It was also getting compression into the radiator. I finally found a hairline crack in the top flange of the sleeve on cylinder no. 3. You might want to check that if you wind up pulling the head. That's what happened to me........

Thanks catd69u, If the coolant in oil issue returns I am going to have to pull the head. I believe I have checked everything else that can be checked without going internal for investigation.