Ensuring you are Ready for the Road Ahead , the Dorman Heavy Duty Coolant Reservoir Cap is an easy twist on replacement for your cracked, leaking, or lost coolant tank cap. Restore your heavy duty truck into proper working condition with this aftermarket engine coolant tank cap that delivers durability you can trust and saves you the cost of dealership prices. 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 .