Some of each. The "bonnet" of a car (you must be English; in the USA, we would say "hood") is generally made of metal, and protects the engine from weather or stray objects and animals. Because the bonnet is generally metal, it's an excellent conductor of heat.
We'd really like to let the extra heat escape from the engine, so we don't really WANT to insulate the hood, but the hood can get TOO hot - so the hood generally has a layer of insulation within the engine to prevent the hood from becoming too warm.
conductor
conductor
insulator.
It is an insulator
insulator
is a pen a insulator of conductor
is water conductor or insulator
is water conductor or insulator
Plastic is an electrical and thermal insulator.
an insulator. that's why it's used in building
bowl is conductor
Steel is a conductor and not an insulator.