Red coolant and green coolant are virtually the same except for the color, according to the University of Tennessee. Red coolant is produced by Toyota, who simply dyes the green coolant to give it a distinct red appearance. In addition to the green and red coolants, there is an orange coolant that is designed to be longer-lasting than the traditional green coolant.
Green coolant is typically good for up to 30,000 miles or for two years. This coolant is designed to keep solutions alkaline with its combination of phosphates, silicates and borates, all of which help inhibit corrosion. After approximately two years, the corrosion inhibitors lose integrity and additional green coolant must be used.
The orange coolant is designed with corrosion inhibitors comprised of organic acids that last much longer than the silicates, phosphates and borates of the green coolant. In newer vehicles, such orange coolants last for five years and between 100,000 and 150,000 miles. In older vehicles, it lasts for four years and 60,000 miles on average.
The orange coolant should never be mixed with the red or green coolants. All coolants should be mixed -with water in a one-to-one ratio to preserve the safety of the car and to provide both freeze protection and boil over protection.