Hi everyone! Just curious what the Franklin drivers are doing to help keep winter oil temps and CHT's up. At 20 F I can't even get into the green with either. Hoping for some pointers. The plane is a M5-220C.

Same here. There is no approved guidance for closing off oil cooler or engine cooling air. I would try experimenting with cardboard covers for the oil cooler with different size holes cut in them. Try different combinations of airflow restrictions to achieve warmer oil temps, but not too warm.

I've seen duct tape over the oil cooler be effective.

PCH wrote:I've seen duct tape over the oil cooler be effective.

That's better than my plan. Easier to vary the amount of coverage.

Thanks for the pointers, guys! I'm experimenting, I'll post some results when I get it dialed in.

I use the silver foil tape used for furnace ducts to cover portions of the oil cooler. At 40F I start covering portions of the cooler. Again, trial and error for individual aircraft. I know some aircraft types have approved inlet plugs but I was concerned that I may cause uneven flows and hotspots by trying to block the inlet air. I have tried various things to limit the volume of air going through the cowling by reducing the exit size. This doesn't change the flow pattern but decreases the volume. A good place to look for ideas is montanabyair.com. He has a BLOG which shows some things he uses to get through a Montana winter.