Engine gaskets and seals for the 2003–2004 5.9L Cummins are vital for maintaining proper sealing throughout the engine. They prevent leaks of oil, coolant, fuel, and combustion gases by sealing joints between components like the cylinder head, oil pan, valve covers, intake and exhaust manifolds, and front and rear covers.

Over time, these gaskets and seals can wear or degrade, leading to leaks and performance issues. High-quality replacements—especially multi-layer steel (MLS) gaskets and high-temp seals—are key for reliability, whether you’re doing maintenance or a full rebuild.