Hyper milers assemble. Looking for winter insulation ideas

I got my first hybrid this summer and the cold season is about to start. I come from a hypermiling background where I had a full belly pan Yaris and was able to get 50mpg+







Now that the temperatures have started dropping, I monitor the engine's temperature with my scan gauge and seeing it drop 10-20 degrees when you start coasting in EV is alarming and explains why these head gaskets fail so often. The best solution I can think of would be some kind of shutter grille that closes when you are in EV mode but it hasn't been cold enough for me to start messing with grill block-offs. For now, I started with insulating the top of the engine and so far, it seems to be helping hold in the heat. No issues with overheating but my intake temperatures are still a little too cold for my liking. I will try to route my intake so it picks up air from the exhaust like I did on my yaris but this will be more challenging since the engine bay is much tighter.

 

Luxury Prius, it's a CT200h. I don't know why the forum doesn't have it as an option to select on my profile yet you can put Tesla or Leaf..