Posted for "Jim Farrell" <jffarrell@msn.com>:
I had a similar high oil temperature problem, except even in cruise. It turned out that the oil cooler discharged into the area behind the engine and this was actually a higher pressure area than the oil cooler inlet.  To check this out I ran tubing to several areas around the engine and cooler. These were run to the cockpit thru the heater valve bypass in the firewall. I checked pressures at the primary engine baffling, the area behind the engine, the cowl discharge and the oil cooler inlet and discharge. With all the tubing labeled in the cockpit I used a 10" differential pressure gage to switch between the tubing to get the differential and static pressures at each point.
It turned out I was actually getting a reverse flow of hot air from the back of the engine thru the cooler (not a good situation).
I made several modifications of the cooler discharge and inlet until the problem was solved. The solution involved extending the oil cooler inlet duct to the front of the cowling and installing a separate discharge for the cooler rather than discharging to the high pressure area behind the engine.  Just for information I found the static pressure behind the engine was about 4" at about 150K. With my present arrangement there is about 2" to 3" differential pressure across my cooler and temperatures are about 180 to 190 Degrees F.

Jim Farrell  235Z