Equip your semi to be Ready for the Road Ahead , with the Dorman Heavy Duty Pressurized Coolant Reservoir, a crucial element that stores engine coolant. By utilizing a robust tank that can hold pressurized coolant, this replacement component is able to aid in the chilling of the engine and radiator during vehicle operation. Built with a durable construction and secure cap to prevent fluid leaks. FleetPride is your First Click in Heavy Duty .