Description

The Cummins Block Expansion Plug Kit 6BEXPK is a complete diesel engine plug kit designed to seal coolant passages within the engine block , preventing coolant leaks and maintaining proper cooling system pressure in Cummins diesel engines. This kit is a direct replacement for Cummins OEM part number 3903402 , making it ideal for engine rebuilds, block service, and complete overhauls. Manufactured from high-quality corrosion-resistant metal , the expansion plugs in this kit are engineered to withstand coolant exposure, pressure fluctuations, thermal cycling, and harsh operating environments common in heavy-duty diesel applications. Properly installed expansion plugs help protect the engine block from internal coolant leaks and external seepage that can lead to overheating or engine damage. Designed for accurate fitment and long-term durability , the Cummins 6BEXPK block expansion plug kit ensures all required plugs are replaced at once, reducing the risk of future leaks caused by reused or corroded plugs. Replacing expansion plugs during an engine rebuild or block service is strongly recommended to ensure cooling system integrity and long-term engine reliability. This expansion plug kit is commonly used in Cummins diesel engine rebuild, overhaul, and block repair applications , including on-highway trucks, industrial engines, and heavy-duty equipment.