As the temperatures get colder, it’s becoming apparent that I’m getting too much cooling via the oil cooler. Even on a reasonably cool day (ground temp in the lower 40’s), I was having trouble getting the oil temperature to 160 degrees. It should be around 180 to ensure more of the water in the oil evaporates. To fix the problem, I created a restrictor plate for the oil cooler air inlet. Basically, this plate limits the amount of air that flows through the oil cooler, which results in less heat transfer in the oil cooler, which yields a higher oil temperature. Here’s a picture. I drilled three 3/4″ holes, rather than just make the plate smaller, so later I can further reduce airflow (if necessary) by putting some aluminum tape over the holes. I did a quick test flight and saw temps nearing 180 in cruise, which is exactly what I was looking for.