Ok, thanks for the info fellas.  I'll pass on the thought of adding an oil cooler.

I just did the Spring Thaw including hills and spirited driving with no extra rad and the oil cooler blocked off.  Mind, I had the Mini rad recored - shop said it would be 80% more efficient that stock core.  Indicated tempertures (Smiths gauge) did not exceed Normal.

HOWEVER, when we head for Arizona in June the extra rad will be in and I will block it and oil cooler off as necessary given temperatures we encounter.  I will have trailer in tow so 1380 will be contending with 2,500 pounds on the road.

Pushing a loaded (+2,000 lbs.) Mini 998 over the mountains in hotter weather engine temps would rise dramatically and oil pressure would fall.  Oil cooler and auxilliary rad cured those related issues.  Flat land, lighter load, different story.

You don't need it.  Years ago, a very valuable contributor here did a test in his 1380 engine'd Austin America, a heavier car than a mini.  He drove up the same long hill with and without an oil cooler at about the same time of day at about the same temperature.  The oil wasn't that warm.

With temps in that range I think a cooler would be over kill. At the very least a themostat in line would be a good idea. We mount them on vintage race cars and quite often have to tape over portions to keep temps in line. To low an oil temp will not purge moisture from the sump. Current day oils are more resillent to heat than those when the little car was introduced.

CTR

The '90 RSP's have an oil cooler.  The simialr year Mainstream model does not.  Does the Mainstream need to have an oil cooler?  What are the typical oil temperatures with and without the cooler?  Summer temperatures in my area in July and August are typically in the 90's F with the lows at night about 60 F.