This Cummins 3976371 Copper Injector Sealing Washer is a Brand New OEM Cummins part.
If you decide not to replace these sealing washers the high compression produced by your diesel engine will escape around the fuel injector. All of your power will escape around the outside edge of your fuel injector. The loss of engine compression will produce a complete mess of the fuel injectors and fuel rail.
This new sealing washer is for the correct installation of the Cummins 5.9L and 6.7L fuel Injectors. A quantity of 6 Injector sealing washers is necessary for a complete injector service. This seal injector washer is a brand new OEM Cummins replacement part that is covered by the Cummins Warranty.