• Jun 11, 2010
Until recently, the only market segment in the United States that had embraced diesel engines was heavy duty pickup trucks. While we were in Maryland this week to drive the 2011 General Motors HD pickup trucks powered by the revised 6.6-liter Duramax diesel V8, we took the opportunity to ask about the now-shelved 4.5-liter diesel. Like Ford and Chrysler, GM was planning to launch diesel engines in its light-duty pickups this year until the economy – and sales – went in the tank.

The Ford 4.4-liter V8 will live on in the 2011 Range Rover and, while there are no current production plans for the 4.5-liter Duramax, many of the prototypes are still running. According to GM sources, a fleet of the diesel 1/2-ton trucks are still being used on a regular basis by GM engineers.

The Duramax was apparently delivering great performance with towing and payload capabilities well beyond those possible with the two-mode hybrid pickup trucks. Even more importantly, the diesel Silverado was on track to achieve combined fuel economy of 25 miles per gallon, compared to the 22 mpg combined rating of the hybrid. At the time the program was put on the shelf, ninety percent of the production tooling was ready to go and it seems a shame that we'll probably never get a chance to drive this engine.

[Source: General Motors]


I'm reporting this comment as:

Reported comments and users are reviewed by Autoblog staff 24 hours a day, seven days a week to determine whether they violate Community Guideline. Accounts are penalized for Community Guidelines violations and serious or repeated violations can lead to account termination.


    • 1 Second Ago
  • 20 Comments
      • 4 Years Ago
      i would like to buy one of the existing ones from one of the engineers when he is done with it should be enough miles left on it to drop it into my 48 chevy pickup . it has a corvette 1993 suspension and it is ready to go man how cool would that be for a hot rod then consider running itr on corn oil geez gives" farm truck "a whole new meaning don't ya know ! call me mister engineer! i am serious!!
      • 2 Years Ago
      The 4.5 diesel won't hit the market until Obama is out of office, and more importantly out of GM. The person he apointed to oversee the restructuring of GM after the bailout was the son of a big money donor. This guy was in his early 30's, a law school dropout, and had absolutely NO experience in the auto sector, BUT his daddy got him the gig. Obama and his anti-energy policies are against the advancement of the internal combustion engine; look no further than the Chevy Volt they tried to force on us. And, all they want to push is high-speed rail. Consumer demand should dictate the market, not a fumbling socialist with an agenda of anti-individualism.
        • 2 Years Ago
        WOW give it a rest.... it was READY under the BULLSH administration but we see how well His 8 years worked out for US.....
      • 4 Years Ago
      Would be nice if they considered making it available as a crate engine...
      • 4 Years Ago
      It was "killed" because of 2 reasons:

      1) Cost. Getting a diesel instead of a gas engine on HD trucks costs you about $9000 extra. Even with a smaller diesel like this, it would still be around $5000-6000 extra. What are the benefits? Better torque, better fuel economy. However in the US diesel is currently about $.30 a gallon more expensive than gas.
      2) Emissions. US Diesel emissions are very strict. The 4.5L would probably have to use some kind of urea filter system like GM's Duramax engines do. That adds even more running costs. If they didn't use urea, they would have to use an afterburn filter, which decreases fuel economy.

      So at the end of the day you'd be paying several thousand dollars more for a truck that gets better fuel economy... but on more expensive fuel and with the same or higher running costs.

      If it cost less to get the diesel they probably wouldn't make much money on it, because diesel engines are more expensive to manufacture. If they could make it without having to use urea/afterburn AND it was only a $2000-3000 jump in price, it would probably be worthwhile. GM truck powertrains have an excellent reputation.
        • 4 Years Ago
        The new 2011s have finally added urea, but up until my 2010, GM only added the DPF (afterburner). These are delete-able (illegally, of course).

        I would love a 1/2t diesel, but until they make one, I'ma keep rockin' the HD.

        -bZj
        • 4 Years Ago
        Don't forget reliability.

        Change the oil regularly, and you should be able to push any pickup diesel well past 500k miles.

        Plus, a 30 cent penalty on a $3 gal of fuel is 10%, and if the diesel is 20+% more efficient per gallon you're still coming out ahead.

        I'd never lease a diesel, but if I were buying a truck (or building a vehicle) to keep for 10 years, diesel is really the way to go.

        And when Gale Banks gets his hands on it, I can only imagine seeing one dropped into an old C5 'Vette..
      John Lucas
      • 3 Years Ago
      I think GM will surprise us with their new pickup truck due next year.
      • 4 Years Ago
      The mpg number is completely fake. It is not possible to get 25 mpg combined from a diesel V8 truck.

      Mercedes ML v6 3 liter diesel does 21,5 mpg combined
      http://www.spritmonitor.de/en/overview/28-Mercedes-Benz/263-M-Klasse.html?fueltype=1&constyear_s=2007&power_s=165&power_e=165

      BMW X5 6-cylinder 3 liter diesel does 23 mpg combined
      http://www.spritmonitor.de/en/overview/6-BMW/43-X5.html?fueltype=1&constyear_s=2007&power_s=173&power_e=173

      Audi Q7 v6 3 liter diesel does 21 mpg
      http://www.spritmonitor.de/en/overview/3-Audi/936-Q7.html?fueltype=1&constyear_s=2007&power_s=150&power_e=176

      All these cars are lighter (unibody, no frame) than pickups and have much smaller engines. Yet not a single one can achieve 25 mpg combined (obviously we're talking about real life mpg here, not some inflated one achieved by performing some non-realistic measurement procedure).


      > At the time the program was put on the shelf,
      > ninety percent of the production tooling was ready to go
      > and it seems a shame that we'll probably never get a chance to drive this engine.

      So once again UFO/Osama/Obama/crisis/recovery/bad weather/ has taken this marvelous engine down. We need to fight, and fight desperately, to win it back. It was getting 25 mpg. No one ever saw this as it never existed, but that's a good thing cause you can't prove it didn't.


      Anyone wanna get real? There it goes.

      A GM pickup with this V8 diesel did 16-18 mpg. At best. Compare with top v6 diesels in lighter SUVs and scale. It was very complex, as every modern diesel is. So it was expensive. As bonus, its exhaust fumes were still much dirtier and cancerogenic than those from a comparable gasoline or gasoline hybrid powertrain. The engine also lost some of its longevity and low cost maintenance due to complexity.

      So it failed as it made little or no financial sense.

      Simple as that.
        • 4 Years Ago
        If by "fake" you mean estimate, I think that is what "on track" was supposed to imply.
        There are some other numbers you forgot to check

        Chevy Silverado gas V8 2wd 4,444 lbs

        Mercedes ML diesel 4,927 lbs

        BMW X5 diesel 5,192 lbs

        Audi Q7 TDI 5,512 lbs
        • 4 Years Ago
        I think a lighter engine and a heavy half ton truck could get better mileage, look at the Dodge 3/4 5.9 six cylinder, I happen to own one with 200K+ and get 17-23 with an overdrive auto trans, imagine a six speed! Look at the Toyota diesels run in Africa and Europe, I have been begging Toyota to bring one to the U.S. for years but they havnt yet. I think the U.S. auto makers are worried what to do with all their gas cars once the U.S. citizens realize what a deal diesels really are! I know on youtube there was a Jeep full size Cherokee with a Dodge diesel 5.9 six in it getting 32 mpg, and still hauling butt! There are tons of guys doing cummins 4 cylinder swaps in jeeps, and audi and other motors in jeeps and having great success! I personally think it is two main things that keep them from our market, one is what to do with all the gas vehicles-mileage wise they will be obsolete, also maintanance wise really, and then there is the clean problem, which for now is fixed via bluetec engines, but that is an expensive fix, and new costly technology, but it will be here shortly probably in small version. I think people would or will switch in droves when they realize what kind of milege they can attain, and what kind of real economy diesels really offer them. I am a total convert, I own a Dodge and a Ford diesel, and am in the process of converting my full size Jeep cherokee to a cummins four cylinder with an auto trans more than likely, I havnt located all my parts yet, but it will happen pretty soon. I think Chevrolet has a good thing sitting there, and it is possible to get more mileage out of a diesel, you just cant expect it to stand up against a Duromax and do that too! Lighter vehicle means lighter duty too.
        • 4 Years Ago
        Decent Rational.

        But we know that a 4.8L V8 4A RWD Silverado gets 14/19 on gasoline.

        Moving to a 4.5L V8 Diesel should raise these numbers by 25% (See Audi Q7 and Mercedes ML)
        -17.5/23.7
        Moving to a "XFE" 6 Speed Auto might gain another 10%+
        -19.25/26.07 or ~22 combined.

        Just the same as the Hybrid. But the Hybrid has an "issue". In comparison to the 4.8L V8 Gasoline engine it gives up 400 lbs of payload and 3000 lbs of Towing. The Diesel 4.5 V8? I bet it would max the Silverado 1500 frame.


        • 4 Years Ago
        Your analysis would be correct, but existing heavy duty diesel trucks often get over 25mpg freeway. And we're talking larger, heavier trucks, with huge displacements.

        So yeah, 25mpg is very possible (in combination with other fuel saving tech).
      • 4 Years Ago
      It's really sad.....this would have been an awesome engine !

      Who is the dumb@$$ who decided to kill this??
      • 4 Years Ago
      This is the truck I want!!! Why won't someone bring it to market??? I don't need a heavy duty truck, BUT I do need a full sized crew cab truck with enough room for a family of 6. I currently own a Nissan Titan because it's got a HUGE crew cab on it perfect for my family and it's got a phenomenal V8 and tranny pushing it along with average economy (for a truck). If I could get a 1500 with a 25mpg diesel in it I'd buy it!!!

      Please guys! Bring these baby diesel 1500's to market!! Ford, GM, Toyota, Nissan, Dodge....I don't really care what brand I'll buy any of them with this motor.
        • 4 Years Ago
        Note: Beat-up used Jeep is only driven when needed... it's a second vehicle, I still drive my car to work every day. A truck with decent mileage would make it so I could have a single vehicle.
        • 4 Years Ago
        +1000

        Who is it that can't see this as the ultimate truck? Are they taking crazy pills? What would be the down side? I've been dying to get a truck, but had to settle for a beat up used Jeep (it was extremely cheap) because I couldn't afford to drive a truck. If they made one that got decent fuel economy and had SOME towing ability (enough for a small boat or a U-haul) I'd be all over it. Make it a 4x4 and they wouldn't be able to make enough of them. Who's brilliant idea was it to cancel the program?
      Bill
      • 4 Years Ago
      they need to put these in the canyon as well , it should fit if they can fit in a 5.2 liter gas job . performance would be crazy and great mileage to boot . while i'm at it when are they gonna make the canyon/colorado look more like the fullsize? these trucks are too ugly and my ZR-2 is gonna be worn out soon . i want a cool looking truck , not something that looks like it took its styling cues from a honda element.
      • 4 Years Ago
      If you're looking for a pickup with decent payload/towing capabilities that'll get 25+ mpg combined, then I suspect the Mahindra will be your only choice.

      I also suspect that there's a lot of, *ahem*, pressure to keep it off the U.S. market.
      • 4 Years Ago
      Who killed the half decent diesel.... ;)
    • Load More Comments