A Brief History of Diesel Engines at Cadillac
Tracing Cadillac’s ignominious history with that “other” fuel.
For the first time in its 21-year lifespan, the Cadillac Escalade will offer an optional diesel powertrain when the fifth-gen mega-hauler goes on sale later this year. That's good news for those who may want to add a bit more towing capacity and fuel efficiency to their Escalade, but to those who remember this isn't Cadillac's first brush with the "other" fuel, this announcement likely triggered more than a few unpleasant flashbacks to Cadillac's diesel history.
Toward the end of the tumultuous 1970s, GM began a two-pronged effort to both capture sales of diesel passenger car sales from the likes of Mercedes-Benz, Volkswagen, and Peugeot, and to prepare for the impending Corporate Average Fuel Economy (CAFE) regulations that went into effect for the 1978 model year. Oldsmobile was tapped for a diesel powertrain that would proliferate through GM's entire passenger car portfolio, as this was still of the era when GM's various branches developed proprietary engines.
In classic GM-at-its-worst fashion, cost-cutting was top priority. To reduce development time and keep the budget as small as possible, engineers essentially dieselized the existing Oldsmobile 5.7-liter (350 ci) small-block gasoline V-8 with the intention of keeping shared tooling between the diesel and gasoline versions. The block was strengthened for the diesel variant, but the head bolt pattern carried over from the gas V-8, resulting in common head bolt failures across the board thanks to the diesel's much higher-compression nature. GM also left a fuel-water separator out of the final design, leading to corroded injector pumps and ruined fuel system componentry.
Before issues wormed their way to the surface, things looked positive. America still reeled from the gas crisis, and a full-size sedan that claimed nearly 30 mpg on the highway was an attractive proposition. Sales were strong, as GM conquered 60 percent of the passenger diesel market in 1981 with 310,000 cars sold with the Olds diesel under the hood.
Inevitably, this initial success devolved into total disaster. Engine failures were absurdly commonplace for the adapted Olds oil-burner, leading to dealers and mechanics often swapping out the diesel lumps for regular gas-powered engines, while various affected parties levied legal action at GM for this colossal failure, culminating in a class-action lawsuit forcing the automaker to pay up to 80 percent of the cost to replace engines.
Production of the Olds diesel ended in 1985, but not before it slithered under the Cadillac crest. The 1978 Seville was the first diesel Cadillac to afflict the general public, packing a wheezy 125 hp and 224 lb-ft of torque, a sad figure that later dropped to a pathetic 105 hp. By 1979, the entire Cadillac lineup offered the Olds diesel, a roster that included the Cadillac DeVille, Fleetwood Brougham, Eldorado, and the aforementioned Seville.
For a moment, GM doubled down on diesel power, refining the horrendous 5.7-liter V-8 into a strengthened and reworked 4.3-liter "LS2" V-6 designed for transverse front-wheel-drive applications. With a different head pattern and additional upgraded hardware, the LS2 V-6 had a fighting chance at righting some of the wrongs, even if it churned out a disappointing 85 hp. Unfortunately for the hardworking engineers, the V-6 only made it to the 1985 Cadillac DeVille and Fleetwood before immediate discontinuation.
GM was soured on diesel passenger cars Stateside for the next 30 years, only tentatively dipping a toe back in the oil-burning market with the Cruze Diesel in 2014. Elsewhere, demand for diesel remained strong, so GM subsidiaries Opel and Vauxhall continued to slot itty-bitty diesels into their passenger offerings.
Even Cadillac got in on the Euro-diesel game, albeit briefly. The weird Saab-designed Cadillac BLS sold from 2005 through 2009 offered two versions of a Fiat-sourced 1.9-liter turbocharged diesel four-cylinder, offering up a respectable 150 hp and 180 hp. Remember, since the BLS was essentially a reworked Saab 9-3, it could be ordered in both sedan and wagon forms, with or without a manual transmission. So yes, for a few model years in Europe, Cadillac offered a manual diesel station wagon.