How Oldsmobile killed Detroit’s diesel dreams

Long before Volkswagen’s Dieselgate made headlines and broke hypermiling hearts, and eons before fanboys were burning french fry oil or rolling coal across the Midwest, oil-burning engines were reviled by the vast majority of drivers in the United States. Perceived as dirty, noisy, and rough-running, diesels had been almost entirely relegated to an industrial role where they powered backhoes and dump trucks, not the shiny new sedans and coupes found in your nearest new car showroom.

Bolstered by the positive, if tepid reception given to the diesel cars that Mercedes-Benz had been selling for several years, however, and punch-drunk from a string of energy crisis body blows, by the late 1970s Detroit finally took notice of the alternative fuel’s potential. General Motors, in particular, paranoid about losing market share to the raft of fuel misers making their way across both oceans, figured it could simply dab some diesel across its product lines in a bid to satisfy drivers feeling the pinch at the fuel pump.

It was a fateful decision that would have an outsize impact on the diesel market in the U.S. for decades—one that would crystallize the image of the fuel as a smoky, clattering disaster and keep diesels out of American-built passenger cars until well after the dawn of the new millennium.

On the cheap

Although today GM is often lambasted for not being bold enough with decisions relating to automotive technology, that risk-averse culture can be traced back to end of the Me Decade, when the company started stuffing as many untested electronic gadgets and gizmos as possible into otherwise pedestrian cars in a bid to convince buyers it could go toe-to-toe with the Japanese. The supreme confidence with which the General approached its technological prowess in those days gave birth to monstrosities like the Cadillac 8-6-4 multi-displacement engine, the paragon of “concepts that were so far ahead of their execution that they rarely shared the same time and space when the driver turned the key.”

It’s puzzling, however, that diesel engines of all things would be the company’s next big miss. Purveyors of heavy-duty trucks and actual corporate master of subsidiary Detroit Diesel (it’s right there in the name), GM managed to ignore its own institutional knowledge in the process of designing its very first passenger car diesels, leaving the task to a put-upon team of Oldsmobile engineers forced to make do with the tiniest of budgets and shortest of timelines.

It was a strategy born of expediency and cost-cutting, two words that rarely combine to create automotive excellence. Doing as they were told, members of the development team were forced to stick with the same bore and stroke found in Olds’ existing 350-cubic-inch gasoline engine to save on retooling costs. With one arm tied behind their backs by boardroom bean counters, they did their best to make the design play nice with diesel fuel.

This isn’t as easy as it might sound. Switching from a spark to a compression ignition (which relies on high cylinder pressures to ignite diesel fuel) puts a lot of stress on a motor. In particular, the block itself and the head bolt strategy need to be strengthened past what a gas motor typically requires.

It’s even harder to get things right when accountants attempt to override the laws of physics and force the use of the original bolt pattern and bolt type as the gasser, despite the increase to a compression ratio three times that found in the stock motor. Other penny-pinching misfires included a missing water separator (not approved despite the prevalence of water in diesel fuel at the time), and a lack of proper bench time before putting the unit on sale, which lead to adventurous buyers also being tagged in as beta testers. At the very least, the purse strings were loosened to allow for the 350’s block to be strengthened to the point where it wouldn’t explode when attempting to merge at highway speeds.

Bad on paper, worse on the street

If all of the above sounds like a recipe for disaster, then you’re 100-percent correct. Despite breathless ad copy proclaiming “better than 30-mpg on the highway!” and a (scientifically dubious) driving range of close to 700 miles per tank, problems with the 1978 Oldsmobile Delta 88 with the new LF9 diesel began almost as soon as it went on sale.

Head gaskets blew on a regular basis because—surprise, surprise—the 10 bolts cribbed from the gas engine weren’t enough to maintain a tight seal between the head and the block under boost. Fixing the problem by replacing the bolts with equally-inferior, dramatically over-tasked factory parts simply prolonged the eventual munching of the motor’s internals as coolant filled the cylinders.

Then there was the water separator issue, which in its absence allowed moisture to accumulate inside the fuel system and rot it out, or in some cases lead to an early end for the fuel injection pump. Owners who attempted to deal with the water-in-fuel issue themselves by dumping alcohol into the tank ended up destroying their fuel system seals in the process—something they might have been warned against had anyone bothered to inform customers how these newfangled diesel motors (occasionally) worked. This was on top of a number of smaller issues that made the Oldsmobile diesel unreliable at best and an expensive boat anchor at worst.

Let’s say, however, that you lucked out and somehow ended up with a version of the Oldsmobile diesel that clung on to dear life long enough for you to put some miles on it. The driving experience itself was… underwhelming. With 120 horsepower and 220 lb-ft of torque on tap when operating at peak performance, the engine wasn’t exactly a screamer lugging around heavy GM metal, and the three-speed autobox matched with the diesel—scooped from the company’s compact car program—had its own reputation for giving up the ghost early and often. Then there was the noise, the smell, and the smoke—all vital characteristics of the unrefined, and underdeveloped Oldsmobile motor that further served to undermine public interest in diesel engines at the time.

Casting a long shadow

Perhaps more culpable than any other factor in the case of what killed the diesel car in America was GM’s stubborn insistence on staying the course. The miserable Oldsmobile LF9 alone was sold in an astounding 29 different models under the Olds, Chevrolet, GMC, Pontiac, and Cadillac banners from 1978–85 (alongside its brief 1979-only 263-cubic-inch LF7 V-8 partner in crime), a move that served to expose a huge segment of the car-buying public to one of the worst drivetrains in the history of motoring.

The overall effect of GM’s massive cloud of diesel smoke was so negative that, when the company did finally get things right a few years after the Oldsmobile’s debut (with a string of decent diesel V-6s found in mid-sizers like the Buick Regal and the Chevrolet Celebrity), no one was interested, which led to a hard cut-off on all passenger car diesel efforts by ’85. It would be more than 30 years before Detroit would take another chance on dancing with the diesel demon in anything other than a truck.

A final, albeit minor footnote of the Olds diesel folly is that the early ’80s, soot has worked to obscure a number of other one-off fuel misers from the Big Three that relied on transplanted import engines rather than in-house drivetrain efforts. Chevrolet stuffed a 51-hp Isuzu four-cylinder between the front fenders of its forgettable, but popular, Chevette subcompact that was largely ignored; Ford tapped Mazda for a similarly-weak four-banger that could be found in the Ranger pickup and the Tempo sedan; and even Lincoln got into the act with its Mark VII luxury coupe, which picked up an M21 straight-six turbo diesel from BMW for the 1984 and ’85 model years.

Unlike their more celebrated German, Swedish, and even French (Peugeot) contemporaries, these domestic Reagan-era diesels don’t get any love, not even from the misfit-friendly rad-crowd. Spend more than a few minutes driving one in modern traffic, or simply trying to get any of these low-tech, high-maintenance beasts to start on a moderately cold morning, and you’ll easily understand why.