The hood of the 82 pickup is getting ratty. Mice chewed into it over a few winters and it is sagging and coming apart.

Looking at a foam type of insulation - like the styrofoam coffee cups, mylar foil faced on both sides. Called P2000.
Figure a one inch sheet as used for home insulation would work well. Clean, reflects heat and would be easy to fit into place and a lot lighter than the pad.

Any downside to using this type of material? I don't think the engine bay gets hot enough under the hood/bonnet to be a problem and as it warms up the reflective mylar should help. In winter I hope the heat reflecting would help keep the engine bay a bit warmer and help with running temperatures. At 25 below zero every little bit helps. (I used it inside the doors, under the carpeting, inside against the firewall and on the overhead. Really helps keep the heat inside in sub zero temperatures and keeps it cooler in the summer as well.

So - any problems you guys know of if I do use this under the hood/bonnet?