Rear Camshaft Block expansion plug with O Ring. Premium OEM quality DCEC Expansion plug & O ring at fraction of cost Note: look for O ring groove in engine block behind expansion plug, some models do not use O ring and there is no groove on engine block for O ring. This plug kit will work for 4bt and 6bt engines and also Dodge Cummins 5.9L 12v, 24V from 1989-2002 Replaces OEM part # 3900687 Expansion plug 3926047 O ring Note: All manufacturer's names, part numbers, and symbols are registered trademarks of these manufactures and supplied for reference purposes only. PB Sales, Inc. is in no way implying that any part listed is the product of these manufacturer's or that we are affiliated with any of these manufacturer's .