Well winter is coming to Mn pretty soon, and I'm thinking about cabin heat for the newly rebuilt Kitfox 4 with 912. I've kind of always liked the idea of a muffler shroud, the muffler is always hot when the engine is at cruise rpm. But in cold weather, the engine may struggle to keep the coolant warm enough to draw a lot of heat off of it. Another option perhaps is run the oil through a cooler in the plane instead of coolant and a radiator. That may suffer the same lack of heat to spare in cooler temps. At least that is my take on it. I've done well with the muffler shroud approach, but have never used either of the other two approaches. I would like to hear from those who have experience with oil or coolant heat in a 912 powered setup. Muffler shroud as well for that matter. I've got to choose a method sooner then later. I don't have a lot of room around the muffler with the motor mount in the way, and that is part of what got me thinking about a different approach. Thanks all, JImChuk