The American diesel dream that never was

On course to become mandatory in 2026, the Euro 7 emissions regulations have already started sinking its teeth into Europe’s automotive landscape. In short, the most stringent of measures to be implemented since Euro 1 twenty-seven years ago, will call for manufactures to have a corporate fleet average of 95g/km CO² across their product range, or face a fine if the target is not met.

With numerous cities calling for the banning of all internal combustion engines over the next 15 years, manufactures have started turning towards electrification in order to comply with not only the average, but also the real-world World Harmonised Light Duty Vehicles Test Procedure (WLTP) fuel consumption stipulations introduced last year.

In a cruel twist of irony though, all of the above can trace its roots back to the infamous dieselgate saga that saw a number of manufactures fingered for lying about their emissions. Even more tragic was that the discovery of dieselgate occurred in the United States where 40 years before, the growing appetite for oil-burners was summarily destroyed by one of the biggest automotive scandals of the 20^th century.

With the implementation of new emissions rules in 1972, manufactures were permitted to rate power outputs according to so-called SAE net standards and not brake horsepower as had been the norm. The resulting effects were laughable power outputs which in some cases, amounted to less than 100 kW from a V8.

On the back of not only this but also the 1973 oil crisis, General Motors (GM), like arch-rivals Ford and Chrysler, had been looking for ways to not only revive sliding, but also conform to the new Corporate Average Fuel Economy (CAFE) regulations that was to become mandatory in 1975.

For 1978, new fuel consumption regulations were introduced calling for all passenger vehicles to average at least 18 miles per gallon (13-litres per 100 km). With most of its engines falling well short, and with the requirements not extending to oil-burners, GM, more than likely smarting from the successes gained by Mercedes-Benz, Peugeot and Volkswagen, headed the diesel route with their Oldsmobile division.

Using Olds’ highly regarded 350 cubic-inch Rocket V8 as a base, GM set about making the myriad of changes to the engine, internally called LF9, in order for it to cope with the added demands needed. In readiness for the new rules, the normally aspirated LF9 with is 5 737 cc displacement  officially debuted in 1977 and despite producing a woeful 88kW/300Nm, promised a minimum combined 22 miles per gallon (10.7 L/100 km), plus a range of nearly 1 000 km. With the outbreak of the second oil crisis two years later, sales soared from 1978’s 33 841 in 1978, to 126 885 in 1980 when Oldsmobile sold a record 910 306 vehicles.

Not wanting to rest on the engine’s apparent success, GM soon expanded its availability to include models from Cadillac, Chevrolet and Pontiac as well as introducing a small 260 cubic-inch V8 called LF7 that lasted from 1979 to 1980 and made a paltry 66kW/220Nm. In addition, the LF9 also become available, until 1981, on the C/K and El Camino pick-ups, as well as the Suburban SUV where it produced 92kW/305Nm.

The initial successes were not to last though and very soon, the Olds diesel is it become known, started exploding. Like the Rocket, the LF9 used the same torque-to-yield head bolts and stud pattern, but in the case of the former, without the necessary strength to cope with the higher pressures of a diesel engine. This resulted in them cracking over time which led to head gasket failure.

With coolant leaking into the cylinders, hydraulic lock would set in, causing bent connecting rods and failed crankshafts. Aggravating matters was the lack of a water separator in the fuel injection system which, given the quality of diesel at the time and the engine’s internal made mostly out of steel, caused it to rust and ultimately in the system failing.

Compounding the LF9 even more was its unfamiliarity with buyers. In attempt to get rid of the water build-up, many owners would pour gas into the fuel tank, a technique known to have worked with the petrol. With the diesel however, the water would bond with the gas, otherwise known as anhydrous alcohol, damaging the fuel injector rings. More bizarrely was the lack of any service personal training on how to the fix the LF9 when it arrived in the workshop. Given its resemblance to the Rocket, the exact same parts would be used to repair it, guaranteeing instant failure.

As if matter couldn’t get any worse, the noisy LF9 was known for stretching its timing chains and for being filled with the wrong type of oil, again as a result of buyer unfamiliarity and due in-part to the wide-scale unavailability of the type of diesel optimised oil recommended by GM.

The horrors didn’t stop there and apart from being an expensive option compared to the petrol, GM, for 1981, lowered the output down to a sorry 77kW/278Nm. In this guise, the Olds diesel sported a stronger block marked DX and came with a raft of internal improvement in order to reverse the damage done by original D block. Unfortunately, the majority of North Americans had had enough.

In spite of GM trying to revive interest by introducing a small 4.3-litre V6 in 1982, the LT6 which was dramatically better but produced a measly 63kW/224Nm, its post boxes were being flooded by class action lawsuits and disgruntled owners having not only spent exorbitant amounts on fixing the engine, but who were unable to receive any form of mentionable resale value. Four years later, the Olds diesel was gone, along with any mass market success oil-burners might have garnered in passenger vehicles.

In theory, the Olds diesel had all the traits on paper of causing a revolution – which it did for all the wrong seasons. In spite of GM giving it a second go with the Cruze six years ago, sales were poor and with the onset of dieselgate two years later, any hopes of diesel making a comeback gone for good.

Note: An earlier version of this piece appeared for the first time in 2016 on autodealer.co.za in a shorter form.

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