For Just Two Years, Toyota Sold The Old Corolla With A Diesel Engine So Efficient Its MPG Would Still Be Considered Decent Today

The multiple oil panics of the 1970s steered automotive development into a novel direction. The horsepower wars of the 1960s and 1970s were replaced with a race to make the most efficient vehicles possible. If gas was to be expensive, then automakers sought to ensure drivers didn’t have to visit the pump as often. Many automakers saw diesel as the secret sauce to excellent fuel economy, and Toyota was among them. For just two years in the 1980s, Toyota sold Americans a super-thrifty Corolla with a diesel engine that was claimed to get as much as 59 mpg, better than most cars can achieve today.

There was a brief period in the late 1970s through the mid-1980s when diesel cars held a solid share of the American market. A perfect storm of factors made conditions ripe for compression ignition engines. The economy had taken a battering through the decade with multiple oil crises, a loss of consumer confidence, and even political turmoil. At the same time, America made a grand effort to protect occupants in crashes and reduce air pollution. Cars were getting dramatically downsized, outfitted with emissions equipment, and adorned with bulky bumpers.

Gasoline prices were high, and Americans were feeling the crunch. Unfortunately, the gasoline engines of the era were only so efficient. While the 1970s did lead to exciting electric car developments, the EVs of back then were closer to novelties rather than practical transportation.

Automakers scrambled to find the next big thing in internal combustion. Many automakers toyed with Wankel engines just to find out that they weren’t nearly as economical or as clean as they hoped. Those same automakers and some others also set their sights on diesel power. Back in those days, the diesel engines that went into passenger cars and pickup trucks weren’t the powerhouses that they are today. Indeed, they often made only morsels of power. Instead, what those old diesels excelled at was fantastic fuel economy. Couple that great fuel economy with the fact that the price of diesel was considerably lower than the price of gasoline back then, and automakers had motivation to switch.

Diesel would become such a big deal in America that, at one point, General Motors sold more than two dozen models that had diesel engines as options. GM put diesels in everything from supposedly sporty coupes to luxurious land barges. They were popular with the public, too, with GM selling hundreds of thousands of diesel cars per year. GM was the market leader in passenger car diesels for years. But it wasn’t just GM, as Mercedes-Benz, Volkswagen, Peugeot, Isuzu, Ford, Lincoln, Nissan, and others all put diesels on the market in the 1970s and the 1980s.

Unfortunately, the delicate factors that favored diesel eventually faded away. But before diesel fell back into obscurity in America, some automakers managed to fire off a couple of diesel models into the market. One of those automakers was Toyota, which managed to sell both the Camry and the Corolla as diesels, if only for a blip of time. The two-year-only Corolla diesel was impressive for its ability to sip only drips of fuel better than most cars today.

Toyota Experiments With Diesel

Toyota was late to adopt diesel power compared to brands from America and Europe. As Toyota says, its journey to diesel began in the 1930s when it studied the work of Junkers. But it would take some time before Toyota put its first diesel into production. From Toyota:

Toyota Motor Co., Ltd. had been conducting research on diesel engines from early on, and around 1939 began efforts to develop a diesel engine, studying the diesel engine made by Junkers. However, this engine did not lead to commercialization before the war because of various factors in the industry and Japanese government agencies. Around the spring of 1948, Toyota established a diesel engine research laboratory inside the Kamata Plant and began R&D on diesel engines anew, inviting such experts as Rihei Nagano and Takeshi Oka. As a result, five prototypes each of the Models Y and Z diesel engines were produced in 1950. During this period, due to a labor dispute that had begun in April 1950, the Kamata Plant was closed in June of that year, and research on diesel engines was moved to the Head Office in Koromo. In the same year, Toyota began testing the Model Y diesel engine using the revamped Model BM truck, and also conducted testing using the revamped Model BX truck in March 1951. Neither of these efforts, however, led to commercialization in the end and research on diesel engines was suspended once again.

Subsequently, diesel engine development was resumed in October 1954 and a prototype of the D diesel engine was completed in August 1955. A modified prototype truck was manufactured by installing this engine in the Model BA truck and, following various types of testing and improvements, was launched as the Model DA60 truck in March 1957. Manufacturing of the D diesel engine was accomplished through cooperation among various Toyota Group companies. Casting and machining of the cylinder block and the cylinder head was done by Toyoda Automatic Loom Works; machining of the crankshaft was performed by Toyoda Machine Works, Ltd.; machining of gears was done by Aichi Kogyo Co., Ltd.; the injection pump and electrical components for the diesel engine were made by Nippondenso Co., Ltd.; and vehicle assembly was performed by Toyota Motor Co., Ltd. Table 1-37 shows the specifications of the D diesel engine.

The performance of a diesel engine greatly depends on the performance of its fuel injection pump, which can be likened to the ‘heart’ of the engine. The D diesel engine used a fuel injection pump made by Nippondenso utilizing a technology introduced by Robert Bosch GmbH of West Germany. The idea of a technology introduction from Robert Bosch was brought to Kiichiro Toyoda, who had become a counselor in the autumn of 1951, by Dr. Tokushichi Mishima. Dr. Mishima was a classmate of Kiichiro from the Engineering Faculty at the Tokyo Imperial University and was a metallurgist known globally for his invention of MK magnetic steel. When the patent on MK magnetic steel was licensed to Robert Bosch, the company asked Dr. Mishima whether any Japanese corporations would be interested in forming a technical partnership. Because Dr. Mishima had served as a research advisor to Toyota Motor Co., Ltd. during its founding period, he brought the issue of technical partnership to Nippondenso via Kiichiro.

Nippondenso and Robert Bosch would collaborate on the design and manufacture of Toyota’s Model D engine (above). At first, Toyota’s prototype diesel sported fuel injection pumps and injection nozzles by Bosch, but when the Toyota Model DA60 5-ton truck went into production in 1957 with the 110 HP 5.9-liter Toyota Model D straight-six diesel engine, Nippondenso had managed to design pumps that performed the same as the Bosch ones. Toyota also set up a separate sales channel, the Toyota Diesel Store, just to sell its diesels.

Something Toyota didn’t note above is that it built its first prototype diesel car, the Toyota AE, in 1940. But World War II would derail further development and production at that time.

Toyota followed up the Model D with the larger 2D and the Model C engine (below), a 1.5-liter 40 HP four-cylinder diesel for passenger cars. The prototype for this engine had the distinction of being the world’s smallest diesel engine for a car, which earned Toyota a medal from the Japan Society of Mechanical Engineers.

This engine went into the 1959 Model CS20 diesel Crown sedan, but would ultimately be a commercial failure. What happened? In 1960, the Crown gained the option of the Model 3R gasoline engine, which offered 90 HP from its 1.9-liter displacement. Consumers overwhelmingly went with the more powerful gas engine, forcing Toyota’s engineers back to the drawing board. It was determined that the only way to up the Model C’s power was to redesign the block, and thus Toyota ended production of the Model C in 1961.

Toyota’s next generation of diesel came in 1964 with the 2.3-liter Model J inline-four, and that engine was notable for having the same output as a gasoline engine. The Model J was installed into the Dyna commercial truck and would become Toyota’s first diesel sales hit. From that point forward, Toyota became so dedicated to diesel power that it would eventually become one of the world’s largest diesel engine manufacturers by units.

The Model J would be followed up by a variety of inline-four and inline-six diesels. America would get Toyota diesels in 1979 from the Toyota L diesel four-cylinder family, which powered the Pickup. That truck might be more familiar to our international audience by its other name, the Hilux. During this time, Toyota did bolt its diesels into some passenger cars, but those were usually larger sedans outside of the more compact “Popular-Size” category.

That would change in 1982 when Toyota made an announcement of a novel advancement in diesel engines.

Toyota’s Modern Diesel

According to Toyota, there was a surging demand for diesel power in small cars. As I noted earlier, diesels were seen as a sort of cure for high gasoline prices. Diesel made big sedans and trucks more frugal, so why not put one into one of the most popular car segments?

In response, Toyota developed what some today call its first truly modern diesel engine, which went into the 1982 “Popular-Size” Corolla and Sprinter, as well as the Carina. From Toyota:

The new Corolla and Sprinter diesel models feature the 1C diesel engine, a superb Toyota development featuring the latest in automotive technology. Already highly reputed for its use in the Corona and Carina diesels, the 1C diesel yielded top level fuel economy values of 31 km/L over a set course at 60 km/h (maker notification values for Corolla Custom DX and Sprinter Special DX with 5-speed manual transmission), plus excellent driving performance and a whisper quiet ride.

Major Hightlights
1. All new Corolla and Sprinter diesel models feature the Toyota 1C diesel engine, with top features including:

– High Fuel Efficiency
The 1C diesel engine is a compact, lightweight, direct-drive OHC powerplant with aluminum alloy cylinder heads and other key advances that mean superb fuel efficiency―31 km/L in the Corolla Custom DX and Sprinter Special DX 5-speed manual transmission models over a set course at 60 km/h.
– Excellent Driving Performance
Both the Corolla and Sprinter diesel offer maximum power output of 65 ps/4,500 rpm and maximum torque of 11.5 kg-m/3,000 rpm. Impressive power added to lightweight vehicle bodies equals outstanding driving performance.
– Quiet Ride
Engine noise has been held to a bare minimum through use of small-size injection nozzles, a low-noise timing belt and mass-damper equipped engine mounts, to provide a luxuriously quiet, relaxing ride.
– Faster Starting
Major improvements in engine start-up time have been achieved through adoption of the Super Glow Control System with fast heating glow plugs. Cold starts have been improved by a device which automatically raises rpms in response to lower water temperatures.
Note: The models described in this release are available only in Japan.

2. To assure a quiet ride, besides curbing engine noise, Toyota has added extra insulation to the engine hood, instrument panel and dashboard.
3. Five sedans are available in both the Corolla and Sprinter series. Sedans in both series include three with 5-speed manual transmission and two with 4-speed automatic transmission with overdrive. Two Corolla commercial-use stations wagons are also offered.
4. The Corolla and Sprinter diesel models feature the same trim and equipment features as their gasoline-engine counterparts.

Toyota’s developments don’t sound like much today. Pretty much any passenger car diesel made in the past couple of decades can start fast, get stellar fuel economy, and can be relatively quiet. However, Toyota’s developments were huge back then. Not too long before the 1C engine, diesels struggled hard to start in cold temperatures due to their sky-high compression ratios, low volatile fuel, and thick oil. Diesel owners tried every little hack, from parking in heated garages to using block heaters. If it was cold enough, you had to sit there waiting for several minutes for the glow plugs to do their job before your diesel would fire.

Toyota’s 1C diesel was among the flood of new-technology diesels that could heat its glow plugs and get the engine chugging in just a few seconds, even if the temperature was below zero outside.

The Perfect Host For A 59 MPG Diesel

These engines went into a game-changing new car. In 1983, the Corolla and its Sprinter received a dramatic new generation that Toyota called the “World’s Most Advanced and Distinctive Cars.” The E80-generation Corolla eschewed rear-wheel-drive for a front-drive layout, and the body was designed around hyper-efficient space utilization. Toyota touted these as small cars sporting the kind of interior volume found in larger cars.

The Corolla and Sprinter also received the latest in aerodynamic tweaking. Japan’s Corolla Levin had a trick feature with its active aerodynamic grille. At normal engine temperatures, shutters in the grille closed, which aided in aerodynamic efficiency while also helping the car heat up faster in the winter. Once the coolant reached a high enough temperature, the shutters opened to feed more air to the radiator.

Another addition that Toyota noted was that, in some five-door models, both the front and rear seats fold flat, turning the whole car into a bed. Toyota boasted that this was a first for Japan’s “Popular-Size” market. Meanwhile, Toyota said, the cars’ low, mostly flat floors added legroom while “special vibration-absorbing body construction” reduced road noise to a new low for Toyota.

Over here in America, the E80 Corolla was a huge deal as it was a part of the New United Motor Manufacturing, Inc. (NUMMI) joint venture between General Motors and Toyota. NUMMI let GM peek behind the curtain to get a look at Japan’s highly efficient car manufacturing practices. Toyota benefited, too, as it was able to better learn American culture and the car business in the country. NUMMI also punched out some interesting models like the Toyota-based Chevrolet Nova, the Geo Prizm, the Pontiac Vibe, the Toyota Matrix, and the Toyota Tacoma.

If you were a car buyer at the time, Toyota was able to add a sweetener to the allure of an E80 Corolla. The brochure talked about an EPA-estimated 59 mpg on the highway or a still impressive 43 mpg combined. Of course, the catch was that you had to get the diesel to get such amazing numbers.

The Corolla Deluxe Diesel you got out of the other side was festooned with a 1.8-liter naturally-aspirated diesel with 56 HP and 76 lb-ft of torque on deck. That car rode on MacPherson struts in front and rear, had power front disc brakes, and carved corners using a variable ratio rack and pinion steering. The turning circle was a relatively tight 30.8 feet, too, making the Corolla a pretty maneuverable family car. Check out this MotorWeek review:

The caveat was the transmission. If you got your Deluxe Diesel as a sedan, you were saddled with a three-speed automatic. Weirdly, if you got the Corolla Deluxe Diesel as a liftback, an automatic wasn’t available at all, and your only choice was a five-speed manual.

One neat stat was that the diesel engine added less weight than you’d expect. A Corolla Deluxe Sedan weighed 2,081 pounds, and swapping the gas engine for a diesel upped that only to 2,275 pounds. The liftback started off with 2,110 pounds and weighs 2,275 with a diesel, or no heavier than the diesel sedan.

These cars were fairly well-equipped, too, featuring options for cruise control, dual-stage air-conditioning, a power sunroof, a tilt steering wheel, alloy wheels, full carpeting, and a four-speaker stereo with a cassette system. Base price for the diesel was $7,398 ($24,330 in 2026) plus $630 ($2,071 in 2026) for air-conditioning and $415 ($1,364 today) for the aforementioned stereo. For comparison, a gas Corolla of the same vintage had a base price of $6,848 ($22,521 today). If you wanted a rear wiper, that was $95 ($312 today). If you wanted the car to have a fighting chance against rust with an undercoating, that was another $119.95 ($394.48 today).

The Corolla actually wasn’t the most fuel-efficient car of its day. The 1984 Volkswagen Rabbit claimed an even greater 61 mpg on the highway. However, the Toyota had two more doors and four extra ponies in the stable. While Toyota never published acceleration times, I would expect a Corolla Diesel to do the job at the high end of the teens. If you wanted a little more spice in your drive, Toyota also strapped a metal snail to the 1C and bolted that into the Camry. But that will be a story for another day.

As another note, while 59 mpg sounds extremely impressive and would beat most cars today, there are a few caveats. For one, there was a national speed limit of 55 mph back then, and modern speeds will hurt that fuel economy. Likewise, the EPA has also revised its testing standards, and the EPA now says that the 1984 Corolla Diesel is good for 43 mpg on the highway, provided you get the five-speed manual. But hey, that’s still pretty good by modern standards!

Toyota’s Diesels Arrived Too Late

In 1984, the Morning Call reviewed a Corolla Diesel, and while it’s mostly complimentary, it also highlights why it sold from only 1984 to 1985:

The new front-wheel-drive Corolla also is the roomiest of all Corollas. With an EPA index of 105 cubic feet (85 passenger compartment and 20 trunk) the car falls right into the middle of the compact class (100-110 cubic feet). Front seat room is good. Back seat leg room, however, does get quite tight when the two front seats are extended all of the way back.

The interior of the test car was done up in that heavy Japanese vinyl, the sort of material that leaves a little to be desired in extremely hot or cold weather, but it wears forever. It is a much better choice of material for families with small children than cloth material. The kids can drop their Big Macs, spill their Slurpies or grind in their Binney & Smiths to their hearts content without any permanent, and very little temporary, damage.

[…]

The test car averaged 46 miles per gallon over Lehigh Valley highways. In addition to the cold temperatures, it was driven over ice, through snow and slush and under more ideal conditions mileage should be even better. The EPA estimates are 43 mpg city/59 mpg highway for the five-speed and 38 mpg/49 mpg for the three-speed automatic. The one drawback with a diesel these days is the high price of diesel fuel. At one time it was much cheaper than gasoline but now it is more expensive. And there are some real rip-off stations selling diesel fuel. I some at one station that had the outrageous price of $1.439 per gallon and this was a self-service station. I didn’t notice the price until I was almost finished pumping. I assumed (sometimes a dangerous thing to do) that since the prices listed for its gasolines (unleaded regular and premium and leaded regular) were reasonable, so was the diesel fuel. So, take my advice and look at the numbers before you start pumping. At the time diesel fuel at other stations sold for a low of $1.229 a gallon to an average of about $1.30 per gallon. Diesel fuel prices are tied in with the price of home heating oil, therefor, if it is a cold winter you’re going to pay more for diesel fuel as the price of home heating fuel goes up.

By the mid-1980s, the game had changed for diesel cars. The price of diesel shot up over the price of gasoline. Since diesel cars were already more expensive than gasoline cars, it now meant that buyers had to pay more for the car and pay more at the pump too.

The other factor holding back diesels in those days was that, by the mid-1980s, gasoline engines were closing the gap between diesels in fuel economy. A 1.6-liter four-cylinder gas engine Corolla was lighter, faster, cheaper, and still got an estimated 43 mpg. In other words, times had changed, and diesel lost its edge in the passenger car market. Most consumers just didn’t see the point of going diesel anymore unless they were buying a pickup truck.

So, one by one, most of the companies that went crazy for diesel cars in the 1970s and the 1980s gave up, leaving only weirdo holdouts like Mercedes-Benz and Volkswagen. Toyota came into the game too late and missed out on the great diesel car sales of the late 1970s.

A Weird ‘Regular’ Car Today

Today, the diesels are so rare that I couldn’t even find one for sale to show you. Sadly, rust has taken so many Japanese cars from this era. A lot of these cars were also treated as expendable family cars, and were used up before being sent to the junkyard in the sky. Yet, the diesels aren’t particularly desirable among typical enthusiasts. People aren’t really clamoring for one of these like they are for the AE86. So, if you do find a diesel for sale, I wouldn’t expect it to cost a ton of cash. I found a rather clean example that sold for only $4,000 a year ago.

I think this story is a perfect encapsulation of what the car market was like for that short period following the economic turmoil of the 1970s. Automakers and car buyers were so desperate to save a buck that hundreds of thousands of diesels sold each year, and even Toyota couldn’t resist the call. Yet, the only reason that diesels even rose to power was that the conditions were just right.

Still, if you’re the kind of person who likes cars from the 1980s and wants something that’s just a little different than what everyone else has, maybe finding one of these diesels is the ticket. It seems that nobody is really chasing them down, and I think we’re at the point where even a well-maintained mundane car from the 1980s is going to get some attention. Only in your case, you’ll slowly pass by every gas pump in town as you make your way to the car show.

Top graphic images: Toyota; DepositPhotos.com