The Dorman Heavy Duty Pressurized Coolant Reservoir ensures you are Ready for the Road Ahead , being comprised of durable plastic to serve as a reliable overflow for storing the expanded coolant generated by engine heat. When the engine cools, coolant retreats back into the radiator. Engine problems that can be seen as symptoms within the reservoir are an overfilled reservoir, white smoke from the exhaust, and oil in the coolant tank. Failing coolant reservoir signs include a pool of coolant under the truck, suggesting a crack or leak in the tank. If your heavy duty truck is showing any of these signs, this heavy duty coolant reservoir is your preferred solution, boasting simple installation and strength to withstand vibrations and heat exposure. Dorman has a distinguished reputation in the heavy duty truck and trailer aftermarket, manufacturing a variety of parts for a complete repair. Through advanced engineering, Dorman successfully checks into today’s most common failures to figure out the why, ultimately delivering modern solutions that not only match OEM parts, but solve known issues. FleetPride is your First Click in Heavy Duty .