Quote: Also consider that if black was so much better at cooling, NASCAR cars would have black radiators where even 5* would be a great benefit.
They run the grill taped up most of the time anyway so obviously cooling isn't an issue. Besides, as previously mentioned, the temp is controlled by the thermostat. It doesn't matter how much heat the rad dissipates, the thermostat will maintain its preset temp.
Everyone seems to be thinking along the lines of "running cooler". Not so. Operating temp is controlled by the thermostat. BUT, if you shut down the engine the car with the black rad would cool down faster.
