I first noticed this back in April after a long road trip. The deterioration has kept to a minimum since then, as I try and drive it only to and from work now, but it is still noticeably spreading. I'm almost certain it's heat related, and while the temperature gauge never goes past halfway, we all know how vague the 4th gen temp gauges can be. The hood does get pretty damn hot...I remember it steaming when we got some rain back in March/April.
I have no hood insulator, but then again I haven't had one since I've owned the car (over 3 years now). Any ideas on what this could be, and if it is heat related, why my engine bay would be so much hotter so suddenly?
Oh yeah, I know my car is dirty. Central Valley dust can be a b!tch.
EDIT: Oh, and the two dents on the front passenger's side portion of the hood are from someone throwing a lawn chair on it overnight a couple years back.
Thanks for your help gents (and/or ladies)!