For Just Six Years, The Cheapest Diesel Pickup Truck In America Was A Small Chevy That Got 31 MPG

America has been enamored with the diesel pickup truck for decades. Usually, these trucks are hulking beasts with the power to pull mountain ranges and enough luxury to outclass a German car. But what if you want something a lot smaller? Back in the 2010s, General Motors had just the answer with the Chevrolet Colorado Duramax. For just six years and for a floor of an affordable $35,080, truck buyers in America got a shockingly capable inline-four diesel pickup truck that got a whopping 31 mpg on the highway. Today, they’re a somewhat unknown secret to getting a cheap diesel pickup truck.

In the years leading up to revelations uncovered in the Dieselgate emissions scandal, diesel fuel was seen as a promising alternative to gasoline. Automakers told the public that diesel cars and trucks were much cleaner than gasoline. European countries subsidized and incentivized the use of the fuel. So many people picked up diesels that the oil burner became the default fuel for Europe. Yep, there are instances in which the gasoline version of a car is rarer than a diesel, which might sound wild to Americans.

Diesel even took off here in America. While our adoption rates were never as high as Europe’s, marques like Volkswagen and Mercedes-Benz spent more than two decades repairing the awful reputation diesel earned in the 1980s after the high-profile bungling of GM’s diesel efforts. In the years leading up to Dieselgate in the 2010s, Volkswagen of America reported that around a quarter of its yearly sales went to diesel models. Some VW enthusiast models sold more diesels than gas engines.

Other automakers took notice and wanted a piece of the pie, leading to a very brief period here in America where you were able to get diesels in everything from Jeep Grand Cherokees to Chevy Cruze economy cars. Mazda wanted in on the diesel action, too, aiming to beat Volkswagen at its own game. But, it seemed that Mazda didn’t know that VW was playing with a stacked deck, and Mazda’s diesel development took so long and made so many compromises that its Skyactiv-D engine was a dud on arrival in America.

In the years since Dieselgate, the word “diesel” has understandably become a dirty one. In Europe, diesel market share plummeted from being the dominant fuel to one with only a small share of the passenger vehicle market in a handful of years. Many of those sweet diesel cars were also canceled here in America. Now, diesel has retreated back to what it does best, and that’s powering lumbering beasts like heavy-duty pickup trucks, highway tractors, and construction equipment.

Yet, one automaker continued toiling away at diesel tech, believing in a future mostly everyone else had given up on. In General Motors’ eye, diesel wasn’t really the bad guy; it was Volkswagen. The Wall Street Journal reported that General Motors believed it could rehabilitate diesel and then fill the void left by Volkswagen of America’s canceling sales of diesel vehicles.

The result was that, for a weird time post-Dieselgate, GM was slinging some truly weird diesels, including the Chevy Equinox of all vehicles. But the plan also gave us the short-lived and awesome Chevy Colorado Duramax and its GMC Canyon Duramax sibling.

A Duramax That Isn’t American

In 2016, General Motors announced huge plans. GM had already experimented with putting diesel power in the Cruze in the years before, and while the Cruze diesel wasn’t exactly lighting sales charts on fire, the automaker was doubling down. Set to join the Cruze were the Chevrolet Equinox diesel, the Chevrolet Silverado 1500 Duramax, the Chevy Tahoe, the Chevy Suburban, and the luxury equivalents of all of those vehicles. Yep, there was even a wicked Cadillac Escalade diesel that I wish I had gotten the chance to test. The list also includes our two aforementioned mid-size trucks.

It would be easy to see the Duramax branding and assume that the engines in these units would be homegrown products. For more than two decades, the big and ferocious Duramax V8 engines that power GM’s heavy-duty trucks were major engineering efforts from GM’s Powertrain division here in America.

Instead, when GM wanted to put diesels into its smaller vehicles, it turned to its European powertrain division. From my retrospective:

[It] started with the General Motors Global Propulsion Systems Torino group in Italy. As Automotive News Europe writes, GM Turin was chosen to be the heart of diesel development. The technical center, which Automotive News Europe says was created after the GM-Fiat Powertrain joint venture failed in 2005, has a primary function of reducing engine fuel consumption across the GM portfolio.

The Torino facility was responsible for the development of the Opel 1.6-liter “Whisper Diesel” that was mounted into the Cruze, Equinox, and Terrain vehicles. As GM noted to Automotive News Europe in 2018, it had five diesel engine families in production at the time. Of those diesel families, only the 6.6-liter Duramax V8 wasn’t designed in Torino. Yep, if you have a diesel Colorado with the 2.8-liter four or a diesel Cruze with the 1.6-liter four, engineers at this technical center had a hand in bringing your engine to life.

GM confused some in the automotive industry when it sold off its European operations in 2017, but kept the Torino technical center anyway. GM said it kept the Torino center as it saw the facility as an important piece of GM’s internal combustion development. The facility would later be sold in 2020.

GM’s choice to turn to Italy wasn’t a completely random one. As David Tracy noted in that story, Italy has long been the destination for American automakers wanting to plant smaller engines into their vehicles. Chrysler’s brands have famously sourced their smaller diesels from Italy’s VM Motori for decades.

You’ve Seen This Engine Before

The interesting twist in this story is that the 2.8-liter inline-four Duramax housed in the Chevy Colorado and GMC Canyon is technically related to VM Motori.

In 2007, General Motors, which used VM Motori engines in its European portfolio, purchased a 50 percent interest in the engine manufacturer from Penske Corporation. In 2011, General Motors spent $200 million developing an engine plant in Rayong, Thailand. There, GM built VM Motori four-cylinder diesel engines for the local market and named them the Duramax XLD25 and the Duramax XLD28.

Fiat scooped up the other half of VM Motori from Penske in 2011, then bought out GM’s share in 2013. GM didn’t walk away entirely empty-handed, as it got to split the rights to the VM Motori A428 2.8-liter four-cylinder engine with Fiat.

This engine was best known for being the successor to the R428, the engine used in none other than the Jeep Liberty CRD. The A428 used the same overall design as its predecessor, but employed more modern technology, including piezoelectric fuel injectors and additions like larger head bolts. The A428 was one of the diesels built in Thailand for Southeast Asia, and the smaller 2.5-liter R425 was built there as well.

When it came time to adapt the A428 for the modern American market, GM activated its team in Turin to develop a new generation of the engine. This new mill would be dubbed a Duramax with the RPO code of LWN. MotorTrend describes some of the development done in Italy:

Engineers at GM spent more than four years developing this new Duramax version of the 2.8L to meet all air quality standards while being able to satisfy the requirements of customers all over the U.S. This meant designing a clean diesel package that operates much smoother and quieter than the international version. Noise was minimized with the use of custom injection programming along with physical upgrades such as hydraulic motor mounts, a centrifugal pendulum vibration absorber in the torque converter, a metal cover for the timing belt, a steel plate on the bottom of the aluminum oil pan, lots of insulation on top of the engine, and a new compressor wheel design for the turbocharger.

The variable-geometry turbo on the 2.8L Duramax is similar to the GTB1752VKL unit used for other countries. The pitch and design of the veins in the new compressor wheel were constructed to increase performance and sound characteristics. For those of you already dreaming up ways to increase output, the part number on the display turbo we saw is GM 5548935, and model number “Honeywell M12 EC-5” was on the compressor housing. After spinning the turbine side of the turbo, exhaust travels into a close-mounted diesel oxidation catalyst (DOC), then into a selective catalytic reduction (SCR) catalyst before going through a diesel particulate filter (DPF), and finally out through a Venturi-cooled “bazooka” tailpipe like those on the HD trucks.

There’s no muffler, because the truck meets GM’s guidelines for noise and tone, and it produces less backpressure with a straight pipe after the DPF. The four-cylinder engine’s head is made from aluminum alloy and is secured to the cast-iron block with 10 head bolts. Altogether, the weight of the engine and its emissions accessories add between 261 and 301 pounds more than Colorado models equipped with the all-aluminum 3.6L V-6 gasoline engine (and 440 pounds more than the 2.5L I-4 gasser). In fully dressed form, the diesel engine weighs in at about 515 pounds.

Reportedly, Italy didn’t handle the entire development, and the Duramax LWN had some help from GM offices in Michigan and Germany. This engine uses a fully balanced forged steel crank, dual overhead cams, and 29,000 psi Denso injectors. Not noted above is how the Honeywell turbocharger utilizes water cooling in the turbine housing to reduce heat at high loads.

Scott Yackley, Assistant Chief Engineer for the LWN program, noted to Diesel World that the LWN was subjected to the same validation and testing process that the 6.6-liter Duramax V8s have to go through. Yackley also pointed out that the engine was built to be a truck engine from the start. It’s not a car engine adapted to use in a truck.

Another fascinating thing is that because the Duramax 2.8 LWN started life as an old VM Motori design, the smaller Duramax engines sold in America are actually very different powerplants, even though they sounded somewhat similar. The 3.0-liter Duramax LM2 “Babymax” straight-six used in GM’s half-tons isn’t related to the LWN.

The LWN was introduced in America in the 2016 model year. Like its predecessor, the LWN was built in Thailand and used 55 percent local parts content.

The Colorado’s Intense Development

The Duramax LWN was first bolted into the engine bays of the 2016 Chevrolet Colorado and GMC Canyon. When these trucks were on sale, they were a bit of a rarity. The only other American automaker slinging a mid-size diesel truck in this era was Jeep with the Gladiator EcoDiesel.

The plucky first-generation Chevrolet Colorado, which launched in 2003, was built in a three-way cooperation between GM North America, GM Brazil, and Isuzu. You may remember those trucks for having a fun breadth of engine choices, ranging from the neat Atlas straight-fives to the mighty 5.3-liter LH8/LH9 V8s. Our Thomas once wrote about how awesome and deeply underrated these first Colorados were, and I recommend it.

Sadly, while the platform had diesel engines, none of them were sold to consumers in America. For that, you had to wait until the second generation. In 2012, a new generation of the Colorado went on sale on the global market for the 2013 model year. Car and Driver describes a little bit of the multinational effort behind that truck:

Chevrolet has unveiled its all-new 2013 Colorado, and when the company calls it a global product, it’s not just referring to where the truck will be sold. Its development spanned five continents, but the bulk of the work was done in Thailand-where the truck was introduced-by Brazilian engineers, and GM’s South American Design Center penned the shape. GM first showed a concept of the truck in Thailand (If you are wondering, “why Thailand?” it’s because compact trucks are very popular there), following that a few months later with another concept in Argentina, but the big question is whether or not “global” includes the U.S., GM isn’t saying, but the Colorado seems well-equipped to do battle here in the States.

The answer to that question is yes, we did get the Colorado, but only after GM took the global version and changed so much about it that the two vehicles became more different than they were similar. From a different Car and Driver piece:

But our truck won’t be exactly like the Colorado available elsewhere since 2012, with the most noticeable differences being up front, in the form of reshaped headlamps, new fog-lamp surrounds, a new grille, and more. The swept-back fascia is also a major departure from the blocky design of the new Silverado, a decision made, we imagine, to provide tangible differentiation among the high-end Colorados and low-end Silverados whose prices will overlap. The look falls more in line with the sedan and SUV portions of Chevy’s lineup, which the brand hopes will raise its profile among buyers of those vehicles. Those shoppers will appreciate this truck’s tidier dimensions; it’s five inches narrower, three inches lower, and 900 pounds lighter than the comparo-winning Silverado. So it’s smaller if not truly small.

Chevy tells us that the roof stamping is the only major exterior component shared with the global version, while a new boxed and hydroformed frame is closely related to the Silverado’s and increases structural rigidity and improves crash performance versus the global Colorado. Inside, the instrument panel and dashboard have been completely redone and in higher trim levels will feature a touch screen running Chevy’s MyLink software. The Colorado and Canyon will be assembled in Wentzville, Missouri, alongside the Chevy Express and GMC Savana vans that will continue to be built in the facility.

The Colorado was also subject to some intense water testing during its development. According to GM Authority, the GMT 31XX platform was subjected to a dunk tank test where water was brought up to the truck’s rockers. This was because GM knew its customers in Thailand drove their trucks through floods during the rainy season and wanted to make sure the new trucks would survive.

GM then fired 825 gallons of water per minute at it for eight minutes, ensuring the truck could survive a severe storm without leaks. Other tests included fording through a 50-foot-long water trough, firing at ports and vents with high-pressure sprayers, and then misting the truck. That last test was done because the small water droplets of mist can get into areas larger drops can’t. So, the trucks needed to combat that situation, too.

The American Colorados and Canyons had to go through the same testing, so the idea is that you’d be able to take the Colorado through some seriously wet stuff while remaining dry inside and still operational at the end of the day.

General Motors says that one focus of the second-generation Colorado was fuel economy. Yes, these trucks were designed to be burly off-roaders and hard workers, but in chasing buyers who might have been moving up from a sedan or a crossover, GM wanted those people to enjoy decent fuel economy.

The result was another impressive lineup of engines. The smallest engine was the 2.5-liter four, which was good for 200 HP and 191 lb-ft of torque for up to 27 mpg. The biggest engine on deck was a 3.6-liter V6 with 305 HP and 269 lb-ft of torque for up to 25 mpg. The little four netted a towing capacity of 3,500 pounds while properly-equipped trucks with the V6 hauled 7,000 pounds.

The Rare American Mid-Size Diesel

In 2016, GM gave the Colorado and the Canyon another engine option with the Duramax LWN. In the Colorado and Canyon, it was good for 181 HP and 369 lb-ft of torque. It was a little shy of the four-cylinder gas engine on ponies but offered 100 more pounds of twist than the V6. Despite this, the diesel option wasn’t exactly meant to be a torque option, but to allow the Colorado to be the truck to break the mythical barrier of 30 mpg.

Despite this, Car and Driver notes, putting a diesel into the Colorado and Canyon turned them into hauling beasts:

All that torque means that the Colorado Duramax is the best compact truck yet devised for towing duty: The strongest gas-powered model can offer 7000 pounds of towing capacity, whereas a two-wheel-drive diesel is rated to tug up to 7700. Go for the 4×4 diesel and the tow rating drops by 100 pounds, but Airstream’s big, 28-foot Land Yacht travel trailer has a base weight of 6586 pounds, thereby leaving the Colorado Duramax owner at least half a ton of room to add options, water, and cargo like 1200-thread-count sheets. And without the turbo-diesel’s deep well of low-end torque, the gasoline models won’t be as comfortable towing any size load.

[…]

While towing a 4000-pound horse trailer that GM just happened to have lying around, the diesel found its voice. The engine is not very loud, but the clatter of the engine’s compression ignition is apparent. It’s not a bad sound and may in fact be reassuring to some owners as sounding the way a diesel should. But it’s definitely there. What’s also there is an integrated exhaust brake, a device also known as a “Jake Brake,” that uses engine exhaust pressure to regulate downhill speed without over-reliance on the four-wheel disc brakes.

Chevrolet priced the diesel at $3,730 above a comparable gas truck. According to Autoweek, the cheapest way into a Colorado Duramax was to get it in LT trim with rear-wheel-drive. If you didn’t need a 4×4 system, you got the truck for just $33,420 before options, which wasn’t bad! A snazzy Z71 with four-wheel-drive and the diesel was a still reasonable $39,265.

MotorTrend held onto a Z71 tester for a year and almost 30,000 miles and sang a lot of praise:

There’s nothing in our fleet as flexible as the Colorado Duramax. It’s a rolling Swiss army knife—whether my weekend plans were running local errands, filling the bed with building supplies, road tripping, or off-roading, the Colorado was always ready for anything.

In the grind that is driving in the Los Angeles area, the Colorado is big enough to comfortably tote around four adults yet still small enough to plug a tight gap in traffic or parallel park with ease. The Colorado is great on the highway, too, with a quiet, comfortable cabin and excellent visibility. And when the road disappears, our Colorado Z71 more than holds its own off-road, taking me deep off the beaten path at Death Valley National Park and elsewhere.

All the while the most exceptional thing about the Colorado was its engine. The Duramax 2.8-liter turbodiesel I-4 only makes 181 hp, but its 369 lb-ft of torque gets the little(ish) Chevy truck moving with authority. It never left me wanting for more power, even if the six-speed automatic sometimes took a bit longer than I’d like to downshift and get in the meaty bit of the Duramax’s powerband.

The publication noted that while Chevy claimed up to 31 mpg highway with the Colorado, its tester averaged 23.2 mpg over the 28,158 miles. That doesn’t sound impressive until you see that the same truck with a gas V6 netted an average of 19.5 mpg in MotorTrend‘s hands. Sadly, the Colorado Duramax got demerits for being more expensive to fuel and service over a gas truck, but the publication concluded that the extra cost was worth it for the better drivability and fuel economy.

GM made the diesel available widely across the line, including the extra mighty ZR2 off-road trim. Yep, for a while, Americans were able to buy a somewhat small off-road capable pickup truck with a diesel engine. In case you’re not in tune with GM offerings, ZR2s had access to locking front and rear diffs, Multimatic aluminum-bodied, remote-­reservoir shocks, two inches of lift, skid plates, rock rails, up to 10 inches of suspension travel, and 265/65R-17 Goodyear Wrangler DuraTrac tires. The low-end torque of a diesel isn’t just great for towing, but makes a truck a neat mountain goat of an off-roader, too.

With that being said, not everything was great. Early Chevy Colorado and GMC Canyon Duramax diesels had some severe teething issues, as I noted in a previous piece:

Sadly, these engines have also earned a nasty reputation. How bad has it gotten? A Chevy Colorado forum has a thread counting the number of catastrophic engine failures experienced by LWM owners. This will be worth looking into at a later date, but unfortunately, there are dozens of reports of total LWM engine failures.

Those early engines have apparently suffered from wrist pin failures, injector failures, which result in holed out pistons, unexplained metal shavings, shattered rocker arms, and ring failures. Read through failed engine reports, and stuck or otherwise faulty injectors have been named as the root cause several times.

Thankfully, reports of these sorts of failures seem to be mostly clustered around 2016 and 2017 models, with lots of owners of later examples reporting good news with their trucks. But some later trucks and some tuned trucks have also experienced engine failures.

Sadly, despite the praise, the writing was on the wall as early as 2020. Reports about the impending death of the Duramax LWN were circulating then and were made official in 2022. GM also pulled out of Thailand in 2020, closing the Rayong line that spring.

General Motors sold as many of these trucks as there were buyers willing to take them home. As such, they aren’t rare. It looks like you can find Colorado diesels with over 100,000 miles in the upper teens, while examples with under 50,000 miles may be well above $30,000.

For six years, General Motors provided mid-size truck owners something different. Americans were able to get the diesel truck experience, but didn’t have to go big or spend huge wads of cash to do it. But like GM’s other late 2010s and early 2020s diesel efforts, it wasn’t meant to be. Aside from weirdos like me, most people had already moved on from diesel in smaller vehicles. It’s a shame, too, because a mid-size diesel sounds dreamy. At the very least, there are still plenty of these trucks on the road, so it’s not too late to enjoy smaller diesel goodness for yourself.