By J.S. Smith

"As far as I know, Rudolf Diesel and Richard Milhous Nixon had little in common, other than being white guys. But had Herr Diesel kept an enemies list like Nixon, at least one from beyond the grave, I’m certain that GM would have been at the top of the list. No single engine did more to sully the good reputation of the diesel engine in North America than the Oldsmobile Diesel. Nor did any single engine do more to kill GM. The Olds division – one of the few nameplates ever to sell more than a million cars in a year in the USA – may even be among the living had it not been for the diesel that bears its name." Posted By J.S. Smith in Autosavant Features

Like many GM blunders, the fundamental concept was good. In the early 1970s GM was not only the largest automaker in the world, it was the largest corporation in the world period. Most shocking to our younger readers, it was also the most profitable. Yes, kids, GM was once a profit machine-it even made money during the Great Depression.

But back to the early 70’s. GM based its vast cash-generating empire on the sales of large automobiles at relatively premium prices. Sure, GM dabbled in compacts and even subcompacts, but the real money was in Impalas, Delta 88s, LeSabres and Caddys. And they were good, solid cars, with chic styling, zippy acceleration and loads of profit-laden options. Most importantly to the bean-counters in the GM building, they made piles of cash.

Then came the OPEC oil embargo of 1973. Gas prices soared and sales of full-size cars plummeted. People shunned large cars like never before and GM worried, with good cause, that fuel prices and shifting consumer tastes would slay the golden goose. And Americans at the time, like those today, were not willing to pay a premium for a small car.

People at GM recognized that they needed to keep people buying their large cars. At the same time, large cars use much gasoline and people were looking for fuel economy. The solution was clear: put diesel engines in the large cars. That way, the public could keep alive its love affair with large cars without paying in appendages at the pump. This strategy would admirably preserve the corporate profit line. Good idea.

Even better idea: make diesels optional at significant additional cost. The plan was diabolically perfect-sort of what we’d now expect from Exxon or Microsoft. There was, of course, the intermediary step of downsizing the land yachts to more reasonable levels of excess-a job both well-conceived and well-executed with the 1977 model year. Next Exit: Diesel Town.

GM settled on a 350 cid V8 for its foray into oil-burner territory. It also decided that it would be an Oldsmobile engine. I’m not exactly sure why Olds was given the project, but GM often let Olds introduce new technologies, as it did with the Hydramatic transmission and front-wheel drive. Contrary to popular myth, however, the engine was not simply converted from Oldsmobile’s Rocket 350. It was a new design, with the same bore and stroke, but it did use many parts from its gas-powered sibling.

One of problems was that it used too many similar parts-more on that later. But initially, when the cars were thrust before the public for the 1978 model year, it seemed like pure genius. Full-size comfort and luxury with economy car gas mileage. Your gargantuan Olds 98, the one with the red leather seats and power everything, now gets almost 30 MPG on the highway. And when the Iranian Revolution caused a second oil shock in early 1979, was downright prescient. Along with the introduction of the X-cars, GM was miles ahead of the competition and appeared-appeared-to be managed by a psychic cabal of super geniuses.

To put it in perspective, in 1978, Olds made a hair over one million cars. Of that number, 33,841 were diesels. And you had to pay $850 to get one in your 88 or $740 in a 98. The base V8 four-door 88 only cost $5,659, so this represented a 15% premium. By 1980, the diesel was even more popular, and available in the best-selling Cutlass and the Toronado. And Olds made 126,885 diesel-powered cars that model year-out of a total of 910,306-each and every one sold at a considerable premium.* And it soon became available company wide-even in Cadillacs.

Performance left much- namely, everything- to be desired. For instance, the 1979 Cadillac Eldo diesel wheezed to 60 MPH in 16.9 seconds and the quarter mile mark passed in a leisurely 20.7 seconds. When the horsepower dropped to 105 with the 1981 model year, it only accelerated the decline (pun intended, sadly). The 1981 Seville Diesel-Cadillac’s top-line prestige vehicle-limped to 60 MPH in an embarrassing 21.0 seconds.

Putting this in perspective the 1980 Chevrolet Caprice Wagon with a gas V8 reached 60 MPH in 13.9 seconds and ran the quarter in 20.0 seconds. Its diesel counterpart needed nearly six more seconds to get up to 60 MPH, getting there in 19.6 seconds and reaching the quarter in 21.7 seconds.** That’s just plain shameful, even by the anemic standards of malaise era iron.

I am too young to remember the particulars of the Olds Diesel. No one in my family owned one. But I recall a sense of optimism surrounding it. I remember my grandparents saying “Olds Diesel” this, and “Olds Diesel” that. They were GM people working in Lansing, which was an Olds town. The paychecks, until 1984 or so, still said Oldsmobile on them. We built the Cutlass, America’s most popular car. GM even built a new plant in 1979 or 1980-Plant Five-on the outskirts of town to make the diesel V6. The nation was mired in recession, but here was a new plant in Lansing. It was new and exciting. And it would, once again, show the world what GM’s Mark of Excellence meant.

Sure, performance was bad-real bad-but economy was great and the diesel allowed Americans to keep their land yachts. And it allowed GM to reap a handsome profit-and we’re talking a Johhny Depp or Brad Pitt Profit, not some measly Tom Hanks or Ewan McGregor money. It seemed too good to be true.

And so it was.

As previously mentioned, The Olds Diesel used too many parts from the Rocket 350. As the discriminating autophile knows, Rudolf’s cast-iron kinder achieve ignition via compression rather than spark. The corollary is that the high compressions needed to achieve combustion create much higher pressure and stress in a diesel than in a similarly situated gas engine. This means that the head stud pattern and bolt strength needs to be much more heavy duty. Instead of a heavy-duty stud pattern with extra-strength bolts, GM used the same ones as on the gas 350. Remember this.

In addition, diesels rely on a precise dollop of diesel fuel to be injected at precisely the correct moment. And the fuel delivery system has to be precisely calibrated in order to do this. Many of the parts of this complex system are made of steel. Needless to say, steel has a tendency to rust when exposed to water. In addition, water in the combustion chamber is bad-real bad-for diesels. It leads to stuff like the bent connecting rod pictured here. For that reason, an indispensable part of the diesel engines is a water separator in the fuels system. GM, however, dispensed with the indispensable. Remember this too.

Finally, the diesel presented Mr. Goodwrenches at each of GM’s thousands of dealerships with issues they’d never before faced. And neither GM nor dealerships apparently ponied up for diesel training. So they serviced and repaired the Olds Diesel like they would a gas engine. Remember.

These flaws, like Medea’s rage or Oedipus’ quest for truth, inevitably led to a tragic conclusion. The head bolts and studs could not cope with the pressure of the diesel’s compression. This led to head gasket failures. This, in turn, allowed coolant into the combustion chamber. While there, it joined water from the fuel system. Water doesn’t compress-witness the wonders of hydraulics. Thus, the water, plus the weak head bolts, plus the failed gaskets meant the dreaded hyrdralock, which treated your engine’s precious bodily internals like Sherman treated Atlanta. Not good.

So, off the engine goes to Mr. Goodwrench. Who repairs it just like he would a gas engine. And reuses the head studs and bolts, just like on a gas engine. Thus, the main cause of the problem continued unabated. Adding to the carnage, the head bolts and studs were already weakened by the initial failure. So they would fail again. Only sooner and forever.

That $800 or so you plunked down, or more likely borrowed at 18% interest at the time – you know, that cash that seemed like a good investment after the Shah’s ignominious exit-remember that? Your “investment” just laid an egg. A very brown, malodorous one.

So your newly rebuilt engine, only a year or two old, is a pile of scrap iron. Whatever money you saved in fuel economy you probably lost in wrecker bills, rental car fees and lost work time. If nothing else, GM paid for the repairs and replacement. In fact, problems were so legion that GM dealers had a code specifically for diesel warranty repairs-they were AFA: Automatic Factory Acceptance. But GM couldn’t help with your resale value, which was burrowing deeper and deeper into the earth, like the super-heated core of a nuclear reactor.

But there’s more. The water in the fuel system corroded the delicate internal parts, which ruined the system, leading to exceedingly poor performance. And when the Old Diesel peaked at a walloping 125 HP***-in a nearly 4,000 pound car no less-you can’t afford anything other than peak performance. But the internal parts merrily oxidized away, and the precision delivery of fuel fell further and further out of synch with the needs of the engine.

Still more! People with water in the fuel line have, since time immemorial, used dry gas, which is basically a water-absorbing alcohol. So they used the same stuff in their Olds Diesels. But the alcohol destroyed a fuel injector governor ring. This further damaged the engine’s timing.

But it’s not finished yet! The leaking head gaskets also led to loss of lubrication over bearing surfaces, with predictably negative outcomes.

Now comes the cherry on top: the Olds Diesel was unrefined, leaving a cacophony of clatter and rattle in its wake. It emitted a foul, tractor-trailer-like smell. So, when you weren’t renting a car while Mr. Goodwrench further maimed your engine, you got to drive a loud, stinky and laboriously slow car. Mark of Excellence? Not so much.

There were probably even more problems with the engines, but you get the point. Eventually, most of them were solved-anemic performance being a notable exception-but demand declined and the engines retired after 1985. But like other GM disasters-Vega, X-cars, Fiero-it was too late. The damage was done. Reputation is hard to overcome. Let’s face it, you’re not probably going to visit the doctor who mistakenly removed your mom’s right leg, no matter how much he tells you he’s improved. Hell, it tanked diesel sales for a generation.

The Olds Diesel not only tarnished GM’s reputation for building big cars-a market they dominated-but it also dealt another stunning blow to its reputation for engineering and production prowess. Buyers simply could not trust that GM’s cars were well-engineered or well-built. Another disaster that left millions unlikely to every buy another GM car. Another legacy burden GM must overcome if it is to succeed.