I did six years in the Navy as an engineman (diesel maintenance & repairs) and my Chief always complained about running the diesel generators for too long with a light load. Because of the light loads the engines were building up soot and carbon in the cylinders sooner than they should be and increasing the maintenance and repairs required. Anyway my question: Was he full of it? Wouldn't it be burnt off during a high load? And would a cummins truck die early if it was just driven around town empty all day with no load? If so would propane prevent this with more efficient combustion? I want a cummins truck more than I need one.