[Raysp30]

I read somewhere a while back that the Prius or Insight uses a special canister that stores the engine coolant after the car shuts down. It keeps the coolant super-insulated so that it stays hot longer, even overnight.

I'm wondering if there's a $5 mod that would make much difference -- installing ducting insulation wrap around the coolant reservoir.

It might not keep the coolant hot overnight, but it would keep it hotter if you leave the car for 2-3 hours.

Question about this is, would that also make the coolant hotter while running?