1978. General Motors believes it has found the golden ticket to solve the world's fuel crisis: a cheap-to-develop, naturally-aspirated V8 diesel engine. The result? One of the greatest automotive blunders in the history of the car. This was no flash in the pan either. This blunder continued to haunt GM for several years, affecting not only the Oldsmobile brand, but also Buick, Cadillac, Chevrolet, GMC and Pontiac.This is the unfortunate story of the Oldsmobile Diesel V8... an engine that promised to the world, but only managed to deliver a massive disaster. Truth be told, this disaster would go on to haunt the US auto industry for decades. Ah-Hah! The Golden Ticket! General Motors General Motors has been around since 1908. Throughout the company's existence, it has pushed the envelope of car design. Faster, stronger, more efficient, more reliable, more affordable... you can tick all the boxes, and then some.In the Seventies, with an international fuel crisis looming and the US auto industry in turmoil, General Motors invested in the research and development of alternative propulsion technology. From an intensive program developing its own Wankel engine for the upcoming Vega, to turbine-powered cars and trucks, to a coal-powered engine, fitted in a Cadillac Eldorado. The coal-powered mill was actually not a new concept... a German called Rudolph Diesel had experimented with coal dust powering his engine designs more than 50 years before GM's engineers had a go at it.In short, coal didn't work out. Coal may have been much cheaper than gas, but burning coal also produces ash and smoke, while also emitting high levels of sulfur and other pollutants. But as far back as 1973, the link to Diesel's engine design also sparked another idea to offer a solution to the international oil crisis: a naturally-aspirated V8 diesel engine, offering plenty of torque and much improved fuel consumption over periodic gasoline V8s.General Motors Brilliant idea, right? Indeed. But it all went horribly wrong during the development of this revolutionary engine. In an apparent effort to save development costs, GM's engineers based their game-changing new V8 diesel engine on the company's very successful 350 V8 gasoline engine. This theory, again, seemed to hit the nail on the head (er, excuse the pun). The 350 gas engine was well proven, and well-loved. And why reinvent the wheel? But a diesel engine operates at a much higher compression ratio than gasoline engines, requiring a more resilient design that can handle the additional pressure.Wearing their short-sighted glasses, GM engineers retained the gasoline engine's head bolt design and pattern, ensuring that the same tooling could be used for the diesel V8, saving the costs to develop new tooling. It would prove to be a massive mistake. But the erroneous head bolt design would prove to be only the tip of the iceberg. The scandal would even include the supposed side-lining of the engineer that was responsible for the development of the Oldsmobile Diesel V8 after he insisted the engine was not production-ready. Oh, the drama! The Wheels Start Coming Off CadillacGeneral Motors launched the Oldsmobile Diesel V8 in a number of its products in 1978. This included the Cadillac Eldorado, Cadillac Seville, GMC pickup, and many more. Touted as a revolutionary engine that would solve the world's oil crisis by offering a much cheaper alternative to gasoline engines, but also providing reasonable performance, cars fitted with the diesel V8 engine sold like hotcakes.But it didn't take long for the euphoria to wear off, and for the bubble to burst. GM cars powered by the engine soon started breaking down. The inferior head bolt design proved to be the main culprit. After GM had ignored fundamental engineering principles in an effort to save costs, the much higher compression of the diesel engine saw the head literally being blown off the top of the engine.In the gasoline version, spark plugs are used to create an explosion, igniting a fuel-and-air mixture, which results in compression being created. A diesel engine has no spark plugs. Instead, it compresses air to a point where the heat generated through this compression is enough to provide the spark that ignites the fuel-and-air mixture. In short, a diesel engine's compression (or pressure, if you like) runs up to three times higher than a gasoline engine. The Oldsmobile Diesel V8 head simply couldn't deal with that pressure, simply because it was never designed to do so.Here's a much more detailed explanation of the differences between gas and diesel engines: Things Go From Bad, To Worse... To Horrible GM It soon became obvious that the head bolt design oversight was but one of the Oldsmobile Diesel V8's fundamental issues. Another omission, apparently again to save costs, was the exclusion of a water separator. In the late Seventies, diesel fuel quality was not always up to standard, and a water separator served to prevent the injector pumps from corroding. No surprise then, that the V8 diesel engine picked up major diesel pump and injector issues. So if a blown head gasket didn't stop the Oldsmobile Diesel V8, malfunctioning injector pumps did. Alas, there were even more issues. The timing chain running the fuel pump was apparently also prone to stretching. A brand-new automatic transmission system was linked to the Diesel V8, and it also proved woefully unreliable.To top it all off, GM had reputedly neglected to properly train technicians at their dealerships about the intricacies of the V8 diesel engine. It was, to be sure, a disaster.Later, reports surfaced that a senior engineer working on the Diesel V8 had objected to the engine being ready for mainstream production, and had insisted on more time to develop the mill. GM apparently responded by using a loophole to place said engineer on early retirement, and to forge ahead with the introduction of the engine, without the suggested development. What was the big haste? GM was supposedly fast-tracking the development process in an effort to meet the 1979 deadlines set by the California Air Resources Board (CARB), regarding emissions. California represented a massive market, and the GM folks were in for a penny, in for a pound, to get the 'extraordinary' certified, so it could start selling cars.Wikimedia Commons GM supplied a total of nine cars fitted with the Diesel V8 for CARB testing. All nine cars apparently experienced engine trouble, and seven of the units had transmission failures. It was a very, very dark moment in GM's illustrious history. The company soon faced a plethora of lawsuits, disenchanted customers demanding a solution. And by that stage of the game, you'd probably expect some senior management person at GM to put their hand up and say: "Fellas, we got this very wrong. We need to make amends, and restore our customers' faith in the product."Alas. The GM marketing machine continued to herald the Oldsmobile Diesel V8 as the greatest thing since sliced bread, and expanding the engine's application to even more models in the early 80s. This included models like the Chevrolet Impala, the Pontiac Bonneville, and many more. Oh, dear. Too Little, Too Late Bring A Trailer To their credit, GM's engineering department did go back to the drawing board with its 350 V8 diesel engine. By 1981, it revealed the 350 DX version of the engine, complete with a new head design that was able to deal with higher compression, a new head bolt design and torque specifications, new head gaskets, and the engine block casting process was improved, offering a more rigid construction. But by the time the 350 DX eventually made it into GM products, the reputational damage far exceeded any positive points of the reworked engine.General Motors spent millions of dollars in settling lawsuits and for compensation. Tellingly, it is estimated that up to a quarter of all GM products fitted with the V8 diesel engine suffered from major mechanical problems. The Oldsmobile Diesel V8 engine would go on to serve in predominantly GM trucks until 1985, when it was finally discarded, and replaced by the notably better Detroit Diesel V8 range.The Oldsmobile Diesel V8 engine was more than just a technical and financial disaster for GM. It also put a serious dent in the viability of a diesel engine in a passenger vehicle. It would take more than three decades for American motorists to take another leap of faith, en masse, and invest their hard-earned cash in a passenger car powered by a diesel mill.Ironically, we seem to have gone full circle with diesel-powered cars, as hybrids, combining gasoline and EV, are taking the shine of diesel mills. In fact, it seems that the days of diesel-powered passenger cars are indeed numbered.