EPA-mandated truck engines less reliable, but more fuel efficient: Study

ENVIRONMENTALLY-FRIENDLY truck engines mandated by the US Environmental Protection Agency, are less reliable but more fuel efficient, according to the 2012 US Heavy-Duty Truck Engine and Transmission Study.

"At the industry level, the new, more complex engines designed to meet EPA regulations are resulting in problems and downtime," said Brent Gruber, spokesman for JD Power and Associates that conducts the annual study now in its 16th year.

Emissions standards for heavy-duty trucks are causing an increase in engine problems and a decrease in overall satisfaction, said the study, reports TheTrucker.com , of Anniston, Alabama.

The recently released study measures satisfaction with engines and transmissions among primary maintainers of heavy-duty (Class 8) trucks that are one model-year old.

Satisfaction is measured based on engine reliability and dependability; engine warranty; acceleration when fully loaded; electronic control module; accessibility to components for service or maintenance; vibration at idle; maintaining speeds on grades and fuel economy.

Forty-six per cent of those surveyed reported engine-related problems, up from 42 per cent in 2011. The most commonly reported engine problems are issues with the electronic control module calibration (cited by 23 per cent of the owners who experienced an engine problem), exhaust gas recirculation (EGR) valve (20 per cent) and electronic engine sensors (16 per cent).

The average number of engine and fuel problems has increased to 81 problems per 100 vehicles (PP100) from 71 PP100 in 2011. The rise in problems has impacted overall engine satisfaction, which declines to 719 index points on a 1,000-point scale in 2012, compared with 739 in 2011

On the plus side, the average engine service interval has increased to 22,703 miles in 2012 from 20,303 in 2011. Additionally, four per cent increase in fuel efficiency is reported year on year.

"The new engines are proving to be more fuel efficient and allowing greater up-time between service, so despite initial quality issues, the new technology may offer a greater return on investment in the long run," said Mr Gruber.