Cadillac DeVille Fifth Generation (1977–1984) Price Guide

The 1977–1984 downsized DeVille was the shock therapy that Cadillac’s engineers delivered after the fuel crisis. A car 700lb lighter and 8.5 inches shorter than the 1976 model that offered the same interior space. It was the most significant engineering achievement in Cadillac’s post-war history and a commercial success that validated GM’s entire downsizing strategy.

The Car

The 1977 DeVille shed the excess of the full-sized era by switching to the new C-body shared with Oldsmobile and Buick. The 425 cubic inch V8 was replaced progressively by smaller, more efficient units including the ill-fated 350 diesel and the disastrous 4-6-8 cylinder-deactivation V8 introduced in 1981. The 4-6-8 engine (which theoretically deactivated cylinders depending on load) was unreliable to the point of unusable and was discontinued after a single year. Avoid any 1981 DeVille with the 4-6-8 unless the engine has been converted.

Buying

The 1977–1980 cars with the 425 V8 are the most reliable. The 1981–1984 cars with the HT4100 4.1-litre V8 are mechanically troubled; head gaskets and cooling system failures are endemic. The Sixth Generation front-wheel-drive cars followed from 1985.