The Caterpillar C-15 ranks highest in customer satisfaction with vocational heavy-duty truck diesel engines, according to the J.D. Power and Associates 2005 Heavy-Duty Truck Engine/Transmission Study released Tuesday.

The study, based on responses from 2,429 primary maintainers of two-year-old Class 8 trucks, measures customer satisfaction with three vital engine factors: engine quality and warranty; engine performance; and engine noise and vibration.
The C-15 ranks highest among vocational heavy-duty truck engine models, performing significantly above the segment across all three customer satisfaction factors. The Caterpillar C-12 follows the C-15 in the rankings with improved scores across all three engine factors. A Caterpillar engine has ranked highest in the vocational segment five times in a row.
“Caterpillar has consistently raised the performance bar by providing their customers with a high-quality product,” said Brian Etchells, senior manager of commercial vehicle research at J.D. Power and Associates. “The Caterpillar C-15 again receives high satisfaction ratings on nearly every measure, which is evidence of Caterpillar’s ongoing commitment to satisfying customers.”
The study examines engines in 2003 model-year trucks, which were the first affected by the Consent Decree enacted in October of 2002, which raised diesel engine emission standards. To meet the new emission regulations, engine manufacturers had to redesign engines and employ new technologies, such as redirecting exhaust gas back into the engine to burn off more pollutants. The study contains a mix of new- and old-technology engines since the Decree took effect in the middle of the 2003 model-year production.
“It appears the new emission technology may have affected engine performance and quality, as customer satisfaction with both factors dropped significantly in 2005,” said Etchells.
Ratings for average fuel economy have declined considerably from 2004, with the average reported fuel economy dropping below six miles per gallon for the first time in the study’s history. Other indications that the new technology is adversely affecting customer satisfaction include low scores on acceleration when the truck is fully loaded and a sharp increase in the number of engine-related repairs. Additionally, engine components that help reduce emissions, such as exhaust gas recirculation valves, are among the more commonly reported problems.
“This is a common pattern whenever new technologies are introduced in an industry, and the assumption is that the scores for these engines will improve over time,” said Etchells. “Engine manufacturers were challenged in 2002 with producing engines that met the emission standards in the Consent Decree, and also satisfying high customer expectations. With more strict government emission standards on the horizon and trucking companies already feeling the effects of high diesel fuel prices, engine manufacturers now have the chance to differentiate themselves from their competitors by producing an emission-compliant engine that doesn’t compromise quality or performance.”