With temperatures in the low 30s yesterday, my oil was often less than 100 degrees F. Too cool! I had installed a home-made cover to blank off part of the oil cooler, but it was not enough. So today I added 3-1/2" to it. In the photo it's the added plate going to the right. I'll see how it does when I fly next time.
The two rivets were going to be facing the oil cooler fins, so I used countersunk rivets, to keep the rivet heads from digging into the oil cooler fins.