The Caterpillar C-12 ranked the highest in customer satisfaction among vocational heavy-duty diesel engines supplied in 2004 model year vehicles, according to J.D. Power and Associates. Heavy-duty 2004 model year trucks were the second model year impacted by the Consent Decree issued by the Environmental Protection Agency that raised diesel emissions standards.

Compared to engines equipped in ’03 models, the average number of reported engine problems has increased to 74 engine problems per 100 (pp100) vehicles, up from 46 pp100.

“In the 2005 study [which reviewed 2003 models], there was a greater mix of manufacturers using old- and new-technology engines, so we’re just now starting to see the overall impact of the emission regulations,” said Brian Etchells, senior research manager in the commercial vehicle group at J.D. Power and Associates. “Whenever a new technology is employed, it takes a while to work the bugs out. As time goes on and engines are better equipped and designed to follow the emission standards, the number of problems generally decline.”

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