First it was a simple oil-cooler failure. A week later, Adam Metter noticed his ’97 Dodge Ram 3500’s 5.9L Cummins engine developed a knock, as the dualie pulled a heavy trailer over a mountain grade.

Cummins’ 5.9L diesel engines have many wonderful traits, from the simplicity of their design to the durability and reliability of their internal components. However, the powerplants also have parts ...