A buddy of mine has an RV-6 with an O-360 in it, and he built a hinged
aluminum cover plate over the oil cooler and connected a standard
push-pull control cable, like a carb heat cable, to the cover so he can
fine-tune the airflow thru the oil cooler in flight. Too bad we can't
just simply do that to our certified airplanes or it'd make the wings
fall off or something like that.

Ross Richardson wrote:
I built a plate that mounts to the oil cooler, much like the Piper Arrow
kit. It helps, but the opening is too large. Next winter I am going to
experiment with a smaller opening. I believe the Piper winterization kit
hole was 1.5" dia hole. My opening is larger that that. 100F yesterday
in North Central TX, Guess I ought to take it off.