I would always see Police cars in Florida with their hoods propped up at wrecks, traffic detours, etc... I always thought it was for a alternate switch to another set of batteries to run the lights or something to do with the car being able to charge at a idle with the lights on for a extended amount of time. I finally asked a cop, why was his hood propped open with a soda can. Much to my surprise he said, it was because the cars overheat and its so the engine can cool better while they are sitting with the engine running. I personally don't think this would make a difference. I work in Florida, on construction sites, where there is no shade, its all been cleared and I will let my F-150 idle with the air on for hours, I ve never had a issue. I would think a police car, with the enhanced performance package, would have even better cooling. I would also think on a covered water cooled engine, raising the hood, 6" isn't going to do too much, in the way of cooling on a 90+ day. I didn't argue with the cop, just a Hmmm. What's your thoughts? I say it doesn't make a difference. Air has to come in at the radiator, driving it would cool it, but the hood, up? Heat rises, but I still don't think its a difference maker.