Cadillac's 1981 models, including this 1981 Cadillac Series 75 limousine, had a standard variable-displacement V-8-6-4 engine.

1981 Cadillac

The 1981 Cadillac lineup got some underhood changes that would do nothing to stem the slow decline in prestige that came to define the 1980s for Cadillac.  

Coming on the heels of the ill-fated V-8 diesel was another equally problematic engine. This was the variable-displacement V-8-6-4, and it was another costly stopgap prompted by government Corporate Average Fuel Economy mandates (CAFÉ).

Displacing 6.0 liters (368 cubic inches) and tuned for a modest 140 horsepower, the Cadillac V-8-6-4 arrived as optional on the 1981 Cadillac Seville and was standard in the balance of the 1981 Cadillac lineup (replacing Cadillac's conventional 425-cubic-inch V-8).

The heart of the V-8-6-4 was an electromechanical system, developed by the Eaton Corporation, that opened and closed the valves on two or four cylinders (hence the name) when signaled by an electronic module controlling the engine's digital fuel injection.

The aim, of course, was improved economy. This was to be accomplished via the cylinders shutting down under part-throttle, low-load conditions when the car didn't need all eight, such as in medium-speed highway cruising. It was a good idea, but too complex and undependable, and Cadillac paid a big price in both image and dollars once angry consumers began suing for redress.

Few mourned when the V-8-6-4 was terminated after just one year, though persisted in Cadillac limousines through 1982. (Ironically, GM revived the idea in the early 2000s -- though not for Cadillacs -- as "Active Fuel Management," which interim technical advances made utterly reliable and virtually invisible to the driver.)

Fuel economy also figured in the decision to offer a V-6 engine for the 1981 Cadillac lineup. It was the first time Cadillac had offered a six since well before World War II. This one was a 125-horsepower 4.1-liter unit, basically an enlarged version of Buick's 3.8-liter overhead-valve design and supplied by that sister GM division.

The V-6 was optional across the 1981 Cadillac line, limos excepted. Another new extra for the 1981 Cadillac line was an electronic "memory" power seat that assumed one of two preset positions at the touch of a button.

In 1982, Cadillac introduced the smallest model in its history. Read more about this humble addition on the next page.

For more information on Cadillac, see:

  • Cadillac: Learn the history of America's premier luxury car, from 1930s classics to today's newest Cadillac models.
  • Consumer Guide New Car Reviews and Prices: Road test results, photos, specifications, and prices for 2007 Cadillacs and hundreds of other new cars, trucks, minivans, and SUVs.
  • 1970-1979 Cadillac: See how Cadillac maintained its hold on the premium market by adroitly addressing changing consumer demands.
  • 1990-1999 Cadillac: Import competition and a stale image rock once-proud Cadillac. Here's the low-down on Cadillac's come-down.