I’m skeptical. Travelling from Phoenix to North Dakota a few years ago, I stopped at Rudy’s BBQ in Albuquerque bought a rack of ribs, a variety of sides, iced tea and a bottle of sauce to go. I ate half of the ribs and the sides and had the other half-rack wrapped in foil to take along with me. Late the next day, somewhere in Kansas or Nebraska, I stopped and put the foil wrapped ribs atop the engine and resumed my trip. When I stopped to eat an hour later, the ribs were warm but nowhere near hot! I’m no expert, but I’m thinking that as long as the car is moving forward, it stays relatively cool under the hood. If you really want to cook under the hood of the car, I think the car should be parked and running (not terribly efficient, but might get the job done). Would love to hear more from folks that have actually done this.