• Oct 6th 2006 at 8:04AM
  • 15

Those looking for a glimpse into the future of light-duty diesel reliability may be interested in a new study by J.D. Power on customer satisfaction with modern heavy truck powertrains. The 2006 Heavy Duty Truck Engine/Transmission Study ranked engines from the 2004 model year by quality, performance, cost of ownership, and warranty, and revealed what one would reasonably expect from new technology.

An average of 74 problems per 100 vehicles was reported, which represents a 60% increase in trouble over the prior year. This was attributed directly to the emission control systems that were phased in during 2003 and 2004. Fuel economy also declined from 6.04 MPG in the 2004 study to 5.72 MPG - a drop of over 5%. Ranked highest in the study was Caterpillar, and the company's ACERT technology allowed the C12 and C15 (pictured above) to lead the ratings of individual engines. Unfortunately, unless you hold a CDL, it's highly unlikely that either one of them will find their way into your personal fleet.

So, what does this mean for consumers of passenger vehicles? Just as we've experienced the evolution of emission controls on gasoline engines, problems can be expected as manufacturers roll out clean diesel technology. How long it will take to sort out these issues is not yet clear, but we're guessing that things get sorted out rather quickly, and indeed some of the problems that are currently affecting heavy trucks may very well be eliminated before it trickles down to smaller oilburners.

[Source: J.D. Power; the complete press release is posted below the jump]

J.D. Power and Associates Reports:
Problems with Heavy-Duty Truck Engines Increase as More Manufacturers Employ
New Emission Standards

The Caterpillar C-12 Ranks Highest in Customer Satisfaction with Vocational
Heavy-Duty Diesel Engines

WESTLAKE VILLAGE, Calif.: 5 October 2006 -As manufacturers of heavy-duty truck engines strive to meet government-regulated emission standards by implementing new emission technologies, customers are increasingly experiencing problems with their engines, according to the J.D. Power and Associates 2006 Heavy-Duty Truck Engine/Transmission StudySM released today.

The study, now in its 10th year, measures customer satisfaction with the engines in two-year-old heavy-duty trucks (Class 8) by examining four vital engine factors. They are (in order of importance): engine quality (30%); engine performance (26%); engine cost of ownership (22%); and engine warranty (22%). The study examines engines supplied in 2004 model-year trucks, the second model year impacted by the Consent Decree that raised diesel engine emission standards.

To meet emission regulations, manufacturers are continuously redesigning engines and employing new technologies, such as redirecting exhaust gas back into the engine to burn off more pollutants. Consequently, the average number of reported engine problems has increased to 74 PP100 (engine problems per 100 vehicles)-up from 46 PP100 in 2005.

"In the 2005 study, 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 should gradually decline."

For the sixth year, a Caterpillar engine ranks highest in the vocational segment. Vocational trucks are defined as those with body types used in rugged job applications, such as dump trucks, concrete mixers, and garbage/refuse recycling trucks. The Caterpillar C-12 ranks highest among vocational heavy-duty truck engine models, performing particularly well in three of the four factors that determine overall satisfaction: engine quality, performance and cost of ownership. The Caterpillar C-15 follows the C-12 in the rankings.

"Caterpillar in particular has done an excellent job in meeting the challenge of the new emission standards by creating their own innovative emission technology," said Etchells. "Caterpillar's success is clearly evident in how satisfied customers are with their engines."

The study also finds that among the four drivers of engine satisfaction, customers are least satisfied with the cost of ownership, particularly in the areas of routine engine maintenance costs and fuel efficiency. Reported fuel consumption for heavy-duty engines has declined to 5.72 mpg in 2006-down from 5.91 mpg in 2005 and 6.04 mpg in 2004.

The 2006 Heavy-Duty Truck Engine/Transmission Study is based on the responses of 2,529 primary maintainers of two-year-old heavy-duty trucks (Class 8).

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    • 1 Second Ago
      • 9 Years Ago
      I'm no diesel expert but wouldn't it be wise just to follow the european guidelines when it comes to diesel engines.
      • 9 Years Ago
      mattlach -

      Sad but true: The processing required for low-sulphur diesel *lowers* the energy content of the fuel. There's no such thing as a free lunch.

      Yes, US emissions requirements are much more stringent than Europe - and reveal regulatory and environmental biases. Again, take a look at the link I posted earlier.

      Regarding diesel hybrids: I agree with the idea. But as I understand it, typical gasoline engines are always cheaper to build than similar diesel engines (due to higher fuel pressures and compression ratios involved). Add to that the expense of an electric hybrid drivetrain, and it simply doesn't yet make sense. Personally, I see the growing popularity of diesel engines eventually minimizing the cost differences.

      • 9 Years Ago
      European trucks (much better aerodynamics) get around 7.5 mpg. American trucks should ditch the brick style, save lots of money.
      • 9 Years Ago
      This "report" sounds more like an ad for Cat. How'd the other diesel engines fare? Could the fact that the Ford Powerstroke Diesels have had an almost 100% failure rate since '03 hurt the average? I know many people with Cummins engines that have experienced ZERO problems and are all well over 150K miles. I am sure the same goes for the Chevy Duramax. This report just doesn't sound right. IMO.
      • 9 Years Ago
      I think there is an incorrect assumption here that problems being seen in heavy duty diesels will soon be seen in light duty diesels.
      The problems in the heavy duty market are largely due to the adoption of Exhaust gas recirculation (EGR) systems to reduce Nitrogen Oxide emissions. These systems were used in light duty diesels BEFORE they were used in heavy duty engines. It won't be a matter of problems trickling down to light engines but more trickling up to heavy ones.
      The reason Caterpillar appears to be doing better than some of the other manufacturers is that they are not using EGR, but have come up with an entirely new technology (ACERT).
      • 9 Years Ago
      It's not the fuel that's the issue, that is just starting to be phased in now. It' the emmissions controls that they have had to add to the engines that is reducing MPG and causing more failures. I suspect that the problems will be sorted out soon.
      • 9 Years Ago
      Why should this be? The problems should have all been vetted in the european models.
      • 9 Years Ago
      I agree with poster #1.

      I'm having a hard time understanding how th enew low-sulphur diesel requirements are causing LOWER milage. The milage should be going up significantly.

      That being said, I remember hearing (on NPR?) that new U.S. requirements are more stringent than the European ones. Maybe this is a factor.

      I'm just waiting to see the results of the likes of a Toyota Prius with a low sulphur diesel hybrid. Hello 100mpg!
      • 9 Years Ago
      As far as waiting a little for new technology to be "sorted out", my grandpapy had the best advice- "Never be the first guy on the block, as you may find it to be the chopping block". Soooo, wait until someone else does the 20 trips to the dealer for warrenty upgrades. 'eh?
      • 9 Years Ago
      ocnj129 -

      Won't happen. Europe has taken a different approach to emissions - one that favors carbon reduction over pullutant reduction - and therefore diesel over gasoline powered vehicles.

      More details here:


      Personally, I think diesels will eventually catch on in the US, as low-sulphur fuel and technology solve the emissions problems. But Europe has had a distinctly different regulatory environment than the US for some years.
      • 9 Years Ago
      nobody can make diesel engines as europeans. never.

      • 9 Years Ago
      I think that the problem is going to be much worse for the light duty diesels next year when the new standards go into effect. The EGR flow rates have to go way up to meet the new NOx limits and exhaust filters are required to trap particulates. The new US requirements exceed the european standards so we won't have the availability of small diesels from Europe.
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