Cars We Remember: Cadillac’s “Trinity of Trouble”

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1981 Cadillac V8-6-4
Cadillac’s “Trinity of Trouble” included the V8-6-4 engine, an ill conceived Cimarron compact and a diesel engine era all appearing in a troubled three year span from 1980 to 1982. Advertising compliments of General Motors).

Cadillac’s ‘Trinity of Trouble,’ 1980 to 1982

Q: Hi Greg. I really enjoy your answers to reader’s questions, so I’m throwing my two cents in. I know you like Cadillacs and that you’ve owned a few yourself. How about telling us when you feel were the worst years for Cadillac during your years, be it sales or development?  I had a 1971 Cadillac back in the day, but it was a used one.  Barry L., Rochester, NY.

A: Barry, from my point of view, I would say the years from 1980 through 1982 were difficult for GM’s most prestigious brand. I call it Cadillac’s “Trinity of Trouble” three year era. It began in 1980 when the Cadillac Seville, then a pretty nice mid-size Cadillac built to compete with Mercedes-Benz, announced it was “going Diesel” as the re-designed Seville came equipped with a 350-inch GM built diesel engine as standard fare.

This is the same engine GM designed and put in its 1978 Oldsmobile full-size cars, much to the chagrin of dealers and owners who had to put up with lots of parts breakage and mechanical woes.

Cadillac CimarronSimply put, this 350-V8 GM engine just wasn’t designed to run on the different combustion characteristics a diesel engine demands.  Even with the best minds in the business doing the gas to diesel conversion, many a crankshaft and connecting rod let loose with regularity. Additionally, the   Olds design diesel was offered as an option in full size Cadillacs in 1978 and 1979 with few takers.

By 1980, the diesel engine was a little better as to reliability as maybe half as many crankshafts and connecting rods broke. Consumers, meanwhile, never did respond and the Seville Diesel engine experiments lasted through 1985. Luckily, a 6-liter V8 was also available in 1980 and 1981, as was a 4.1-V8 from 1983 to 1985. Luckily, most Sevilles sold in the Cadillac diesel era had the gas engines. A Buick designed  252 inch V6 also joined the ranks in 1981 and 1982 as an option as was a 262-inch V6 diesel in 1984 and 1985, the latter which did nothing to help sales in Fleetwood and Seville lines.

Cadillac’s second big failure came in 1981, when it received well-earned notoriety for its V8-6-4 engine. The 368-cubic inch gas powered V8 came standard in the Cadillac line and as an option on Seville.  Although the theory was sound (and today is a standard feature on modern day V8 engines), Cadillac’s 1981 version of valve train and cylinder management was far from perfect. Consumers cursed the day they bought one, and the experiment lasted but a few years.  Although the engine was available in certain limousines in 1982 and the Seville line as late as 1984, virtually all sales were “normal” powerplants by 1983. This electromechanical design V8-6-4 was rushed to market before perfection thanks to 1978 CAFÉ rules, which stands for corporate average fuel economy standards.

Cadillac Seville Diesel and V8-6-4The third and final big-blow to Cadillac’s once spotless history of quality cars arrived as a new model in 1982. Enter the compact  Cadillac Cimarron, which was built on the same J-platform that gave us the Pontiac J2000 and Chevy Cavalier.  Few consumers were fooled by Cadillac’s upscale Cavalier as sales were dismal. Thankfully, Cadillac pulled the plug in 1988 on perhaps the most “non-Cadillac” Cadillac  ever to come from its design room.

Interestingly, during this Trinity of Trouble period Cadillac was still number one in American luxury car sales.  Granted, the period affected Cadillac’s legendary name, but the manufacturer quickly moved on developed into one of the world’s top class luxury manufacturers.

My two Cadillacs were a 1972 Sedan Deville (similar to yours) with a 472-V8 under the hood followed by a 1975 Coupe DeVille, with a 500-inch V8 lurking. Both were great cars and I have fond memories of them.
Thanks for your letter, Barry.

(Greg Zyla writes weekly for More Content Now, and other gatehouse Media publications. He welcomes reader questions on collector cars, auto nostalgia or old-time racing at 116 Main St., Towanda, Pa. 18848 or email at


Greg Zyla

Greg Zyla