Vintage Review: 1978 Cadillac Seville Diesel – Puffing And Chugging To Deadly Sin Status


(first posted 11/11/2016)      While all the GM Deadly Sin articles generate plenty of lively discussion, there was one car awarded that dubious honor which prompted an especially high level of debate.  The first generation Cadillac Seville was arguably a borderline deadly sin—not nearly as good as it should have been, but a popular and profitable product that did satisfy a lot of buyers who loved the notion of a smaller Caddy.  But what would happen when an Oldsmobile Diesel made its way under the Cadillac’s hood?  Would fans of European Diesels come running?  Car and Driver had some thoughts on that, as covered in the October 1978 issue.



Merely sizing a Cadillac like a Mercedes-Benz did not make it a world class luxury car, especially when it lacked the engineering excellence and quality materials of its German rival.  Likewise, stuffing an Oldsmobile Diesel in the Seville did not make it a legitimate alternative to a 300D.

To be fair, when it was introduced, the Oldsmobile Diesel was initially praised by the press.  Buff books felt it offered respectable performance (for a Diesel) and good fuel efficiency, making it an interesting choice to improve fuel economy in larger, heavier American cars.  Unbeknownst at the time, though quickly discovered, was the fact that GM had cut corners in the Diesel conversion of the Olds 350 V8.  The motor would soon be infamous for blown head gaskets, clogged fuel lines and other serious maladies that prompted numerous recalls and helped turn generations of buyers away from Diesel power in the U.S.



One key issue for the Seville that was readily apparent by late 1978 was the fact that the new C-Body DeVille/Fleetwood and the newly announced E-Body Eldorado were far better, more modern platforms.  The stretched X-Body, which had seemed reasonable as a stopgap in 1975 and 1976, was eclipsed.  The opportunity, of course, would have been for Cadillac to make the 2nd Generation Seville a much improved version of the Americanized “International” theme.  Instead we got an over-the-top bustle back with the lethal Diesel standard.  The bizarrely baroque styling was a complete turn-off to the growing ranks of luxury buyers with more globally-oriented tastes and took Cadillac in the exact opposite direction from where the market was heading.  Talk about a deadly sin!

Compounding Cadillac’s sin was GM’s goal to be a leader in manufacturing techniques, rather than placing emphasis on making a superior car.  Car and Driver editor David E. Davis hit the nail on the head when he stated: “Why should I care how they build them?  What’s important to me is how they drive.”  GM had clearly lost the plot on this simple fact by the late 1970s, and the extent of the damage would be painfully apparent in the 1980s.

As noted in the counterpoints, there was also debate surrounding Diesel-powered luxury cars.  Of course, Mercedes-Benz had built much of their reputation in the U.S. on the functional benefits of the Diesel, which showcased the quality, efficiency and durability of the products from Stuttgart.  For Cadillac, however, the brand reputation was centered on hedonistic luxury and flamboyant style, so the Diesel made for a somewhat odd powertrain choice.  Sure, if you wanted high mileage benefits, then the Diesel made some sense, but for customers forking over $16,582 ($61,401 adjusted) the price of gas couldn’t have been much of an issue, nor did most Cadillac owners intend to keep their cars for a decade.  Pragmatism was never part of Cadillac’s allure, so the trade-offs required by a Diesel (slow, smelly, noisy) were harder to justify, and that was before people learned just how bad the Olds Diesel really was.


The performance tables were a classic example of how certain test results did not actually capture the reality of the car.  On paper, the Diesel Seville looked pretty good in many ways, and bested Mercedes in certain attributes, like quietness.  But GM didn’t excel at the holistic excellence of the product, where the Mercedes-Benz was hard to beat.  Rather, Cadillac selected “key metrics” to “beat” the Germans, but in reality, the Seville Diesel wasn’t surpassing the 300D at all.  Cadillac simply didn’t grasp the evolving motivations of prestige customers.  In more recent times, in a case of “déjà vu all over again,” Cadillac mimics a few European “features”–like responsive handling– and then touts its sedans as “outperforming” BMW by fractional differences on a test track, while failing to match (or even understand) the comprehensive appeal that its rivals offer.  Perhaps GM’s Deadly Sin hubris just hibernates, but never really goes away…