Got a
whole hour of free time (
) so I had a look at the foam insulation I stuck to the oil pan before summer (see top of page). It held up, no melting or any other damage visible either to the foam or the oil pan, so I went ahead and added more. I covered all 4 sides, then added a second layer (I still have enough for another 1-2 layers), each layer is 3mm thick.
Before starting I had the pad heater on for ~30min, then drove into the garage. It was cold outside, the chassis temperature was 4-5°C while the oil pan was 16.5°C, the test piece of foam from before summer was 15°C. Now with all sides covered with 6mm (compared to an isolated 3mm) the oil pan should hopefully hold temp much better.
The underside of the hood has a "blanket", probably for sound deadening but also works as thermal insulation. That's not good enough - I covered the whole underside with bubblefoil, shiny side down. The OEM blanky is still there, behind the foil.
As you can see, the old cardboard-with-alufoil-glued-to-it is still in service, but I plan to replace it with something that will better wrap the top and sides of the engine, instead of just laying on it.