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Oldsmobile diesel; the engine that soured diesel in the US


An announcement by the Volkswagen Automotive Group earlier this month that it might end the sales of diesel powered vehicles in North America for good amidst the ongoing emissions saga, has no doubt sent shockwaves through a market that had been warming up to the notion of passenger cars powered by something other than unleaded or electricity.

As it widely known, the Wolfsburg giant last year admitted to installing so-called emissions cheating software on a reported 11-million models fitted with its EA189 1.2, 1.6, 2.0 and 3.0 litre TDI engines, resulting in the eventual resignation of CEO Martin Winterkorn, fines of up to $18-billion (R239-billion), axing or resignation of key personal, and falling share prices.

The irony was that the software detection originated in the States, a country where diesel had been shrouded in controversy ever since one of the biggest scandals rocked the US-automotive industry 40-years ago.

Amidst ever tightening emissions standards, and with the market still reeling from the 1973 international oil crisis, General Motors had seen the sales of its full-size automobiles plummet as more and more consumers opted for something smaller and more efficient.

In an attempt to curve the crisis but also to satisfy the government’s Corporate Average Fuel Economy (CAFE) regulations introduced in 1975, GM had to reign in the power of its V8 engines, lowering outputs to extreme levels in the name of improved efficiency.   

For 1978, new regulations stipulated that passenger cars had to average at least 18 MPG (13 L/100 km), which meant GM’s last option to turn a profit was to mirror Mercedes-Benz, Peugeot and Volkswagen and go the diesel route.

Not wanting to spend more money on developing a completely new engine, GM turned to their Oldsmobile division with their well-established and popular Rocket 350 cubic-inch V8.

The diesel, officially called the Oldsmobile 350 diesel but referred to by its codename, LF9, shared many of its components with the Rocket, and was claimed to average up to 30 MPG (7.8 L/100 km) depending on the vehicle fitted that it was fitted to.

Arriving for the 1978 model year, the Olds diesel proved popular with sales of 33 841 units that year, rising to 126 885 in 1980 out of the 910 306 Oldsmobile models sold.

GM quickly took notice and on the back of the 1979 energy crisis, began offering it as an option on certain Pontiac, Chevrolet and Cadillac models, even introducing a smaller 260 cubic-inch (4.3-litre) V8 with 66 kW and 220 N.m for that year only.

What happened shortly after the Olds diesel’s introduction though, was the have a massive impact on GM and the reputation of diesel engines in the States.

Like the Rocket V8, the diesel used the same head bolt and stud pattern, the former being unsuitable to cope with the higher pressures diesel engines are subjected to. Over time, these would crack resulting in head gasket failure. With coolant leaking into the cylinders, the phenomenon of hydraulic lock would set in, causing bent connecting rods and failed crankshafts.

In addition, the engine also lacked a water separator in the fuel system which, given the quality of diesel at the time, and the fact that the engine’s internals were made from steel, caused it to rust and lead to failing injectors, fuel lines and fuel pumps.

Furthermore, owners and dealership personal were totally unfamiliar with how a diesel engine worked. Many owners would, in attempt to get rid of the water build up, pour dry gas into the fuel tank. This technique was known to work with the Rocket V8 but with the diesel, the water would bond with the gas, otherwise known as anhydrous alcohol, damaging the fuel system’s injector rings.

Once in the workshop, service personal simply had no training on how to repair the diesel and would fix it in the same way as the Rocket V8, as the parts fitted and the engine underneath the bonnet looked the same. The chances then of the already damaged head bolts being used again was therefore almost guaranteed.

What’s more, the diesel engine was an expensive option over the petrol equivalent. If you wanted it in your Oldsmobile Delta 88 for example, you had to pay an extra $850, a 15% increase over the Rocket.

During the period 1978 to around 1985, power outputs for GM’s non-performance V8’s ranged from as low as 77 kW to as high as 134 kW. The Olds diesel displaced 5 737cc, was normally aspirated and came in three outputs.

Between 1978 and 1980, engines marked with a D in its block produced 92 kW and 305 Nm of torque for commercial use, and 88 kW with 300 Nm in passenger application. From 1980 to 1985, the new DX marked unit made 77 kW and 278 Nm of torque.

As popularity began to dip and problems continued to escalate, GM attempted to revive interest in the Olds diesel by introducing a smaller and much improved 4.3-litre V6 in 1982 with just 63 kW and 224 Nm. The damage had however been done and diesel engine production ended after 1985.

In theory, the Olds diesel had all the traits of being of a success, but was tarnished by virtue of being rushed into production and with little to no understanding of how it worked. Countless lawsuits followed with Oldsmobile, whose sales remained strong even after the scandal, eventually dying in April 2004.

The similarities between the Olds diesel and Volkswagen’s cheating emissions are striking and a classic sense of déjà vu. For a market having seemingly recovered from one diesel scandal, the latest saga involving another has mostly likely sealed the fate of the diesel engine in America. As for South Africans…did the scandal even tarnish VW diesel products locally? I’d say no, since we aren’t emissions crazy.

Article written by Charl Bosch
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