• Mar 11th 2009 at 8:25AM
  • 66
General Motors' 4.5-liter Duramax diesel V8 engine has become the latest casualty of the automotive downturn, as GM has put the promising powertrain on indefinite hold. The General follows Ford, Toyota, and Dodge in dropping light diesel engines from its near-term plans. GM spokesperson Susan Garavaglia told Pickuptrucks.com that the project has not been canceled, and that the General was "still very interested" in using the innovative diesel powertrain in the future.

The 4.5-liter Duramax diesel sounds terrific on paper, with a 25% improvement in fuel economy, 310 horsepower and 525 lb-ft of torque for towing, and an innovative design that cuts weight while also saving $600 per engine. The news will be difficult for fans of the Chevrolet Silverado and GMC Sierra anxiously waiting for a diesel engine in a light duty pickup truck. Still, GM points out that it has a dual-mode hybrid truck that can achieve 40% better fuel economy in the city, along with a full line of gasoline and diesel engine offerings in its truck lineup.

While the 4.5-liter diesel isn't going into GM trucks and SUVs any time soon, the General says it would still consider license the technology to a third party if the deal was beneficial to all involved.

[Source: Pickuptrucks.com]

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    • 1 Second Ago
      • 6 Years Ago
      As much as this engine looks good on paper, there are a couple of problems- It's too close in performance to the big Duramax- it really could do most of the towing/hauling jobs of its big sibling that don't require dual rear wheels. It also isn't really a fuel economy diesel- for econ, something around a 3-3.5l 6 cylinder would have fit the bill much better, with the same performance of a TBI 350.
      This Engine really could be used in any number of 2500 series applications- anywhere a 10ton GCW isn't needed. Would be a good fit for the G-Van, too- fit under the dog-house better and is more compatible with the rest of the drive-train.
      • 6 Years Ago
      So what Diesel engine does GM have that can pass tier 2 bin 5? The exception for 3% of light trucks (basically the Diesel exemption) is over now or will be over soon.

      If GM doesn't offer this Diesel engine, then they will have no Diesel engine to offer. And that doesn't seem likely to me.
        • 6 Years Ago
        You're talking about trucks. Horsepower might as well not be listed for the diesel-loving truck crowd.

        Torque allows big objects to move. RPMs are not your friend. Having to rev the piss out of a pickup truck to get into the passing lane is one of the most miserable experiences in the automotive world.

        Tapping the accelerator and having an F350 get off the line as carefree and easy as a V6 coupe puts the smile back on a truck-driver's face.

        Who cares if the V6 coupe can rev and disappear. You're in a truck. Cruising along normally is reward enough.

        And no, I don't think that the gas engines in the F150, Silverado, or Ram are adequate to get a truck moving from a stop as carefree as a smaller vehicle. Thats why I won't buy another full-size until they bringeth the torque (ecoboost, diesel, etc)

        Its not just a numbers game. Diesel is a different driving experience, and some prefer it.

        Now you're right about the tight times. But that still doesn't mean that 'only 310 hp' is even a number diesel truck buyers put at a premium.
        • 6 Years Ago
        You concentrated on one part of my post and missed the rest.

        GM already has a more powerful (and more torquey) Diesel to offer to people who want one. So this engine would be only for those who want a Diesel but want less engine than that engine offers. Even assuming this gets better mpg than their gas engines and the other Diesel, it still means you are looking at a small fraction of the Diesel truck market.

        I'm not sure who those people are.

        And trucks are not supposed to be as quick off the line as a car. They never have been. Even with traditional torque-heavy truck engines it hasn't been the case.
        • 6 Years Ago
        I take it back.


        GM has a 6.6L turbo V8 to offer. It makes 365HP.

        In tight times when fuel is cheap, I cannot see people paying thousands extra over a gas engine in order to get "only" 310HP. They have the basic problem that things like (most) hybrids have. It increases the price, which reduces the potential customers to only those who don't really need the fuel savings anyway. So you just end up with greenies.

        Suspending this engine seems like a wise move. They can resume it later when it makes more sense.
        • 6 Years Ago
        Whynot: the 6.6l Duramax engine is in a different market than the 4.5L. The 6.6l will only fit GM's heavy duty HD pickups. The 4.5L engine was planned for the light-duty pickups and fullsize SUVs (TahokonBurbanSlade). The 6.6l and the associated Allison transmission won't fit in GM's fullsize SUVs.

        This engine is for the people with a TahokonBurbanSlade, who want better mileage than the gas V8's. Many of these folks tow, so big torque is important. But this engine is not focused on the highest weight towing like the 6.6l. If you have a 5th wheel camper, then you'll get a heavy duty pickup truck, with dual rear wheels, and the 6.6l engine. But for most folks towing with a TahokonBurbanSlade, the 6.6l is simply overkill. Too big, too heavy, too expensive, not efficient enough. The 4.5l would slot between the gas V8s and the 6.6l.
        • 6 Years Ago

        I'm LOL-ing at TahukonBurbanSlade! :D


        Indeed this engine was never intended to replace the 6.6L. That thing is a beast. A 4.5L allows people who would otherwise shy from the 1500 series (and platform-sharing SUVs) to consider it again. I am one of those, and so is pretty much every truck guy I know.

        And since when is it mandatory to respond to every point in a post? Knowing how long-winded I am, I'd take up a page to do that :P

        I agree with your post (as I said at the bottom) with the exception for one point I have a contrasting opinion on.
        • 6 Years Ago
        I still fail to see this customer base who is willing to spend thousands more for a Diesel but is somehow scared by the fuel bills of the larger Diesel.

        It seems like a tiny market to me. No other manufacturer offers two Diesel choices in a pickup right now. I don't see why GM should either. Maybe if the price of fuel goes up again.

        I do appreciate the info that you must get a 3/4 ton truck to get a Diesel engine, I didn't know that.
        • 6 Years Ago
        The LD diesel was never about consumer demand, it was about CAFE. The feds demand unrealistically high MPG without specifying a gallon of what, that means if they are going to sell large vehicles in the future they will need to be diesels - and probably hybrids as well.

        This is delayed because they have no development money. That's all. If GM still exists in 10 years this engine will be in their trucks.

        • 6 Years Ago
        Reality check on this unfortunately stillborn diesel.

        1) Big is right about torque - that price premium doesn't just buy 5 hp. Just look at the numbers and nothing else needs to be said:
        6.0L V8 Gas - 360 hp @ 5600 / 380 lb-ft @ 4200, Hydra-Matic tranny
        6.6 Duramax - 365 hp @ 3200 / 660 lb-ft @ 1600, Allison tranny

        2) So why make the 4.5 when the 6.6 Duramax is available? Lots of reasons. First, cost. The current Duramax premium is about $6K; this engine's premium had been targeted to be around $2K. Note above that the 6.6 has an Allison transmission; common sense indicates that you're going to pay through the nose for a tranny to handle that much torque. If GM could use a high production volume Hydra-Matic, that lowers the cost a lot. GM also did stuff like eliminating manifolds and casting them into the heads. Second reason is volume. As noted before, this 4.5 could fit pretty much anywhere a small block gas V8 could go, which means GM could offer diesel 1500 series trucks, SUVs, and even sedans.

        What really frosts this for me is that after all the idiots in Washington finish their screaming about energy policies and do stupid things like the CARB ruling, they won't do something simple like temporarily adopt the Euro-5 standards for diesels (that lots of great Euro-available diesels already meet) and relax the Bin 2 Tier 5 requirements for a few years.
      • 6 Years Ago
      This is a real shame, but understandable given GM's acute cash shortage.
      Wasn't this the engine which GM was pondering for use in high end Cadillac sedans? It would have been quite a magnficent and frugle performer.
      Here's the problem folks. Our Government cannot decide whether this sort of diesel engine is a viable alternative to standard gasoline engines in reaching emmisions and CAFE Regs. Right now the tax base isn't helping diesel engines at all (un like say in Europe). This lack of decision shows the lack of leadership from our Gvt. Either diesel has a future, or it doesn't. Right now, by default, it seems GM has decided diesels have no medium, or long term future. Let's hope the Gvt sees this as an issue and signals their intent. Manufacturers cannot guess the technical future swings of Gvt. so GM is right to freeze development at this time, unfortunately.
        • 6 Years Ago
        Ian- really GM has only decreed that diesels have no short-term future. The engine that was under consideration for the CTS was the 2.9L V6 from VM. not a bad engine, but a different story.
        • 6 Years Ago
        Actually that other engine, considered for the CTS, isn't the one I was remembering. There was a larger GM diesel considered for the larger STS and DTS that I think was this 4.5L. Maybe others can clarify.
      • 6 Years Ago
      • 6 Years Ago
      will get a 4.2
      • 6 Years Ago
      I was really considering the half ton diesel suburban in the future. I like the size of the sub I already have but wanted the economy and towing of the diesel. I checked back here after a few months to learn that this engine is back on the shelf. I really wonder sometimes. Hybrids are still not all that appealing to me but a diesel is. I scan for duramax trucks daily. I even found a company that will outfit a 3/4 ton sub with a duramax. I guess I'll keep the old one and live with the hope that an affordable diesel suburban/yukon xl will show up in the market. (I'm only 32 so I figure i have some time)
      • 6 Years Ago
      This was the only engine that was going to get me into a new truck.
      • 6 Years Ago
      As much as I love the possibility of this engine, and the rumor also surrounding this being applied to GM's rear driver autos too (read: CTS and G8), if they don't have money to continue development, how do you expect them to survive? This is simply a decision of survival. I am sure they would love to introduce this mill.
      • 6 Years Ago
      The premium cost for diesel? Funny you say that, because this morning I saw for the first time in recent memory diesel selling for 3 cents a gallon cheaper than regular.
        • 6 Years Ago
        You're wrong. Meeting US emissions is quite complex for a Diesel. It's not just what is in there, but how it is used. And there's a lot of testing. Ask Mercedes whose first new-style Diesel in the US was rejected by CARB despite all their efforts because it was shown to not maintain a proper emissions level over the first 100,000 miles life of the car (this led to the lease-only BlueTecs in California, where the cars had to be moved out of the state after the lease).
        • 6 Years Ago
        And no, I don't condone 5-year olds manufacturing entire exhausts.

        But I did actually used to help my old man position pieces of metal for him to weld at a very young age. He'd make me look away from the blue flashy light when he was actually working. Then he'd tell me when to help. Good memories..... anyway,

        'This goes here, that goes there' is quite simple. No moving parts.
        • 6 Years Ago

        I'm not sure what part of the Midwest you're in but I've been all over IL and parts of WI in the last few weeks and diesel is still substantially higher than gas. It has come down in comparison but it's still higher. I doubt GM made this decision based on pricing, though, as fuel pricing is obviously volitile right now.

        There are a lot of costs associated with sticking an engine in a vehicle and getting it to pass emissions, durability, etc. Add to that the fact that it wasn't finishd and I doubt the investment made sense when they really need to sink developement money back into cars.
        • 6 Years Ago
        BMW and VW groups have adapted. The new standards required a rework. Product design and development requires the same phases whether its a new piece or a whole new system.

        But their diesels took LESS time to get on the road in the US than Ford's Ecoboost direct-injection gasoline engine for example.

        Because their 3.0L diesels are so tried in Europe that adapting some filters did the job. Pricey stainless pieces to be sure. Each piece had to be engineered to allow maximum output with minimum pollution. Limiting factor = a new filter, and the time it takes for test results.

        Still not that complex for a company with their siht together.
        • 6 Years Ago

        They are simple because they are simple structures arranged in a simple fashion. Just a catalyst, a filter, and a urea tank. If you think that's complex, you obviously
        never played with LEGO's because a 5-year old could put this

        My gasoline powerd car has 3 catalytic converters. Technically, its
        exhaust system is MORE complex than an Audi diesel for example.

        Its expensive because it requires an entirely different exhaust
        system. They are simple tubes with substrates in them. But they
        are not cheap. Anyone who's ever built an entire 3" exhaust system
        from stainless knows that the material itself can run you hundreds of

        This isn't a diesel issue, its a Ford/Mercedes issue.

        Ford has had some quality control issues with their new diesels. The old
        7.3L International had high-pressure fuel systems and they were
        reliable for years.

        And Mercedes has bad quality control accross the board. How do their failings at everything translate to their diesels being to root cause of all their problems?

        This is an engine for light-duty pickups. Heavy duty pickups sell
        2/3 diesel engines. I'd expect at least 1/3-1/2 of the 1500 series
        to sell with diesels.

        The economics work exceedingly well for trucks. If GM doesn't have
        the money, thats understandible, but your arguments against them in
        HD vehicles is totally invalid.

        • 6 Years Ago

        Your local pump is not indicative of the national average. And
        taxing and subsidies on diesel versus overseas is a moot point.

        Diesel on the national average is $0.10 more than regular unleaded.
        Or about the same as mid-grade unleaded.

        In CA and many parts of the mid-west, diesel is now the cheapest fuel
        you can buy at the pump. Despite the prices in New England, don't base national sales on your local Kwik-E Mart.

        The high-pressure fuel system is similar to that used on Direct-Injection gasoline cars. Not unreliable in any real way.

        Also, the emissions equipment on these diesels are quite simple. If you don't understand them, thats a different story.

        Time to shelve the obsolete arguments. If you don't like diesels, fine. But nothing you said is anywhere near valid.
        • 6 Years Ago
        Here in MA, regular unleaded currently costs around $1.90/gallon. Diesel currently costs about $2.40/gallon. That represents a 26% premium for diesel fuel. While diesel engines get ~25% better fuel economy, the fuel costs are a wash. Add in the extra initial purchase cost for the diesel engine and higher maintenance costs (the high pressure diesel injection system and emissions system are horribly complex), and unfortunately the economics simply don't work.

        In Europe, the governments tax gasoline more than diesel fuel. Here in the US, the reverse is true.
      • 6 Years Ago
      GM is in "survival mode" and this diesel was too expensive $100's Millions to commit to build it, tooling, plant update, etc... too costly today! GM is LAST to make this decision after Ford, Dodge and Toyota all sheved their light truck diesels months (year) ago. Typical sloooooooooooow GM decision making, day late and dollar short!

      If you need the 500+ torque to tow, you need to move up to a 250 range HD truck that offers a diesel and is better build (frame) to handling the tow load.

      Plus, GM is under pressure from Ford with the upcomming EcoBoost 3.5 V6 planned for the F150 (longitudinal layout) at 400hp and 400ft.lbs torque and 23+ mpg at much lower cost ($700+) vs. a diesel ($5,000). Ford is the most aggressive with EcoBoost "off the shelf" technology (DI and twin turbo) with high volume rollout of 750,000 powertrains (6-speed dual-clutch trans.) planned in the next few years. Yes, GM has this technology too and so do most automakers (Ford is not claiming "new" technology, just mass produced), where GM, like others have missed the market for it. Most have applied DI and turbo to "performance-only" vehicles, while Ford is applying it to virtually all vehicles as a means to increase MPG and power in a lower cost powertrain... Its a better idea from Ford!

        • 6 Years Ago
        The diesel option in a light duty truck shouldn't be anywhere close to $5K.

        M-B offers their diesels for $1,000 more and VW adds roughly $2K for the TDI Jetta. BMW adds about $1500 to the cost of a 3-series and that includes the manadatory automatic transmission which is the majority of that cost.

        I think diesel truck engines are that much more expensive because they can be, not because they need to be. Buyers are used to paying the premium and continue to do so.

        I see that premium dropping significantly if these diesels ever make it into light duty trucks.
        • 6 Years Ago
        EcoBoost is right now only mentioned as being offered as a performance option (350HP Mustang, 350HP Mercury, 360HP Taurus SHO). There are rumors of it coming to the F-150, if they offer it, we can argue whether 350HP in a truck constitutes a "base engine" or a performance model when that time comes.
      • 6 Years Ago
      I guess this means we won't be getting the CTS-D :(
        • 6 Years Ago
        What about that diesel V6?
      • 6 Years Ago
      Excellent. There is a tiny glimmer of hope here.

      Sounds like the idiots running GM are starting to realize they are now in a lower place of Consumer perception than Hyundai, and are changing their product offering to emulate the bottom feeder car companies.

      Since Hyundai has no V8s, announcing the elimination of all V8 gasoline engines is the only thing that will get them more tax payer bail out money ( they need $10,000,000,000.00 a month just to keep the doors open ).
        • 6 Years Ago
        "Since Hyundai has no V8s"

        Huh? Not only does Hyundai have a V8 - the Tau which offered in the Genesis - their V8 is on Ward's 10 Best Engines list.
        • 6 Years Ago
        I guess Toyota is a bottom feeder also for following the same path??
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