2018 GM Marine 6.6L L5P

The all-new L5P Duramax 6.6L turbo-diesel engine advances the General Motors legacy of powerful, quiet, and durable diesels. The next-generation redesign offers more horsepower and torque than ever for easier, more confident hauling and trailering.

Along with a 19 percent increase in max torque over the previous Duramax 6.6L, the redesigned turbo-diesel's performance is quieter and smoother, reducing noise at idle by 38 percent.