oil temp

[airtids]

Back on Fire Patrol here in B.C. as of last week, and have a concern: Rear oil temp was running about 30 degrees cool of red line with an OAT of 10 degrees C at 8500ASL- Way too high I thought, I don't recall seeing that last year. First course of action was to switch Vernatherms front to rear, to see if the problem manifests itself in the front engine, identifying the problem as a faulty valve. Well went out yesterday, and sure enough, the front engine temp is up about 230DegC, but the strange thing is the rear is STILL running about 230 as well. Any Suggestions? What SHOULD the oil temps be running at under those ambient conditions? Running 2300RPM at 19"MAP at 50 degrees rich of peak around 9000ASL
Thanks