Four Decades Ago, Nissan Made A Diesel Truck So Economical It Got Better MPG Than Almost Every Pickup Today

The 1970s and the early 1980s were a dark period in automotive history. Fuel prices shot up, the economy went into the toilet, and consumer confidence spiraled. Cars pulled a sharp U-turn. Automakers no longer placed a grand importance on power, but on fuel economy. In the early 1980s, Nissan declared itself the king of the pickup truck fuel economy wars with the Datsun King Cab diesel, a truck that got around 40 mpg on the highway, or, per Nissan, better fuel economy than any truck with a gas engine.

One of these obscure trucks has shown up for sale at a Toyota dealership in Kentucky, and it’s a time capsule to the kinds of trucks enthusiasts crave today.

Back in the 1970s and the early 1980s, automakers drew buyers into showrooms by boasting about great fuel economy. In those days, the diesel engine wasn’t seen as the block of brute force that it is today, but the winning formula to beat high fuel prices. Vehicles with diesel engines may have been slow, loud, and smoky, but they promised that their buyers wouldn’t have to visit fuel pumps as often. Even better was the fact that depending on region, diesel fuel was also cheaper than gasoline, too. As I’ve written about before, the allure of diesel was so attractive that major players like General Motors placed diesel engines in pretty much everything with four tires.

The 1970s were also when America got to experience a moderate explosion in light-duty diesel trucks. Automakers had occasionally experimented with implanting diesel power into light trucks for a couple of decades by that point, but the 1970s really gave automakers a good reason to lean into the technology.

In the late 1970s, you could buy an International Scout with a Nissan CN6-33 straight-six diesel, GM pickups with the infamous Oldsmobile diesel V8, or a Dodge D-series or W-series with a Mitsubishi 6DR5 straight-six diesel. The import game was also ramping up during this time with Toyota offering up its own four-cylinder diesels. Going into the 1980s, Volkswagen stepped up to the plate with its Rabbit Pickup diesel, and Isuzu brought diesel power to America in the P’up truck, the Trooper II, the Chevrolet LUV, and the Chevrolet S-10.

In 1981, the EPA conducted fuel economy testing that subjected all kinds of vehicles to a simulation of what an average driver’s day might look like. Out of the other end, the undisputed truck champion was the Volkswagen Rabbit Diesel, which scored an impressive 38 mpg average. At the time, the VW was also the highest-rated diesel truck, returning 54 mpg in EPA highway testing.

However, the caveat was that the Volkswagen was a car-based unibody front-wheel-drive coupe utility. If you wanted something more of a traditional body-on-frame pickup truck that still got great fuel economy, the EPA’s testing suggested your next best choice was a diesel Datsun.

Planting Stakes In America

I’ve covered Nissan’s truck history in the past and you can read that by clicking here. The short version is that Japan’s best-selling trucks until the early 1950s were little three-wheeled jobs. The nation’s automakers did build four-wheeled trucks — Nissan’s first of which debuted in 1934 — but the majority of workers went for the simple and reliable trikes. That changed after World War II when buyers began demanding more from their trucks. Eventually, the four-wheeled truck eclipsed the three-wheeler.

The ancestor to today’s Datsun King Cab is the Datsun 120, which launched in 1955 as the truck version of the Datsun Sedan 110. For Americans, the Datsun truck story begins with the Pickup 220 (above), which was displayed alongside its equivalent sedan variant at the 1958 Los Angeles Auto Show. This truck was a simple unit, featuring the chassis and drivetrain of the Datsun 1000 sedan. Nissan says this was the first “compact” truck sold in the U.S. and the truck that helped Nissan become a household name today.

The Datsun 720 launched in 1979 as a replacement for the 620.

This truck brought Nissan’s latest developments into one truck. It was available with the long cab established in the earlier 620s and the so-called King Cab extended cab that was introduced later in the 620’s cycle. Nissan says the 720 was designed to have a similarly slick exterior design as the 200SX. Nissan also notes that it was during this time when it noticed that people were beginning to use trucks for recreation rather than just work, so it tossed in a four-wheel-drive system for the first time on this model line.

Depending on where you live and what model year you find, the Datsun 720 might have been badged as a Nissan, but America got it as a Datsun. We also didn’t get the four-door 720 that other nations got. Instead, we got a regular cab and the King Cab, with Nissan advertising the King Cab heavily. Look at the cute jump seat!

The biggest accomplishment of the 720 came halfway through 1983 when Nissan brought its Nissan Motor Manufacturing Corp. plant online in Smyrna, Tennessee. This plant marked Nissan’s first American-built truck and also planted the seeds for what Nissan would become in America today.

However, perhaps overshadowed by this was what the 720 King Cab achieved on its own. In 1981, Nissan advertised the 720 as an innovative piece of equipment. Brochures, which didn’t mention “720” but called the trucks by their trim levels, bragged about three different 4×4 models, bold colors, tie-down hooks, a five-speed manual transmission, intermittent wipers, and a tailgate that could be operated with just a single hand. Of course, Nissan was especially proud of the King Cab, which didn’t have four doors, but purported to carry four people with the use of jump seats.

Fuel-Sipping Truck

Americans had their pick of two powertrains. The base engine was Nissan’s 2.2-liter NAPS-Z hemi four-cylinder that made 98 HP. Nissan said if you got this engine with 2WD you’d get up to 36 mpg on the highway. But if you were absolutely obsessed with fuel economy, Nissan also offered its truck with a 2.2-liter inline-four SD22 diesel from the Nissan Diesel division, formerly Minsei Diesel. This unit, a smaller relative of the SD33 that was the optional engine in the International Scout made just 61 HP, but the lack of power was said to translate to a thrifty 39 mpg highway and 33 mpg combined.

According to Nissan, this made its diesel truck the “King of the Diesels” and more thrifty than any gasoline-powered truck on the market. As we established earlier, it also had better fuel economy than any pickup that didn’t have a VW badge. You also got it bolted to a five-speed manual transmission.

If you go back to the EPA’s 1981 simulation, which included tons of idling and other wasteful driving, you’ll find that the Nissan 720 scored 33 mpg during the test, just a few numbers shy of the VW’s 38 mpg average. The closest runner-ups were the Isuzu P’up/Chevy LUV diesels, which got 32 mpg. The closest gasser was the Mazda B2000 at 27 mpg and a reproduction Ford Model A truck at 28 mpg.

Put another way, the EPA said that a Datsun King Cab diesel truck got about the same fuel economy in stop-and-go traffic as a modern city car. But the Datsun was a real truck with a 1,400-pound payload, a 2,725-pound curb weight, and the aero of a brick. Some people claim to get above 30 mpg in real life, too, which is great. If you go by just EPA numbers, that’s better than most gas trucks on the market today.

Technically, Nissan’s claim to be the “King of Diesels” was only true if you didn’t consider the VW Rabbit to not be a real truck. Nissan also wasn’t ahead of the rest of the competition by a particularly wide margin. Perhaps that’s why the finer print of Nissan’s advertising focused on gas trucks.

I have not found production data on these trucks, but it appears that Nissan made as many of them as there were people to buy them. Sadly, America did get the short stick in some regard. The diesel option was offered only on rear-wheel-drive trucks. In 1984, the engine was upgraded to the 2.5-liter SD25 inline-four which made a slightly healthier 70 HP, then the diesel option was removed from the U.S. market after 1985.

This Time Capsule

Regardless of how many of these were built, it seems that finding a clean diesel isn’t easy, yet its gas-powered siblings seem to show up for sale with some regularity. But it’s worth remembering that the majority of these trucks are over 40 years old and most of them were used as transportation rather than collector items. That makes this 1981 Datsun pickup at Gates Toyota a bit of a treat. Someone took great care of a truck that most people would never care about today.

The dealership is short on details, saying that the truck presents in overall good condition with a remarkably low 74,695 miles on the six-digit odometer. Assuming that mileage is correct, and the truck’s condition seems to suggest it is, that means, on average, this truck traveled only 1,697 miles a year.

Flip through the pictures and you might be shocked at how nice this truck is. There isn’t a crack in the dash and the seats look like nobody ever really sat in them. Even the pedals have pretty low wear. The damage I could find includes the torn shifter boot, a crack in the driver door card, and what looks like the beginnings of rust under the passenger door. But that’s nothing for such an old truck.

Sadly, we don’t get to look at the jump seats or at what the inside of the bed looks like, which is a shame. But I do love how this truck came from an era when automakers listed everything out on decals.

When new, a truck like this would have sold for around $7,500 ($27,197 in 2024). Today, Gates Toyota in Richmond, Kentucky, thinks this truck is worth $11,097. It’s certainly a beautiful rig and while you won’t struggle hard to find a 720 in decent shape for sale, the diesels appear to be somewhat rarer. This is a case where many of our readers will say that rare doesn’t always equal valuable, but this price doesn’t seem bad at all for a classic truck.

This Datsun time capsule is just another look into that wild time when automakers thought diesel was the future. Indeed, diesel was the right fuel for the right time as gas prices were high and gas engines guzzled fuel. Almost as soon as the price of diesel shot up and gas engines became more efficient Americans went back to buying gassers. Still, this truck is a sort of fun look into what used to be. It was a truck marketed for its fuel economy first rather than capability or any other truck trait.

(Images: Gates Toyota, unless otherwise noted.)