The Most Hopeless Car Engines of All Time

A car’s engine, as you might expect, is one of the most vital and expensive parts of the entire machine, and many power units are feats of engineering innovation and development.

From the legendarily long-lasting likes of the Rover V8 to the advanced hybrid engines we see in modern cars, there have been a lot of excellent engines over the years.

However, for every fantastic, long-lasting and powerful engine, others are plagued with reliability issues so stark they require frequent engine rebuilds.

Here are some of the worst, most pathetic car engines ever made.


Oldsmobile Diesel V8

An engine so bad it destroyed interest in diesel cars for an entire country, created endless misconceptions that endured for decades and is sometimes simply known as “the diesel debacle” in the United States, Oldsmobile’s hopeless line of diesel engines was a bad idea executed in the worst way possible.

To cut down costs, reduce factory complexity and avoid confusion with conversion kits, Oldsmobile effectively converted their standard petrol engines to accept diesel fuel.

This not only makes for grim performance numbers during a time when American car makers were just escaping the Malaise Era, but the head bolts also kept blowing off, leaking gaskets caused water locks and many engines gave up and failed spectacularly less than 30,000 miles after being driven out of the showroom.

It was so bad that after a widespread class-action lawsuit was filed, the US government enacted so-called “lemon laws” to improve consumer protections against defective cars and other products.

Whilst most companies did learn their lesson, Subaru also had a disaster trying to make diesel engines in their trademark boxer layout.


Cadillac 8-6-4

Variable displacement is a common feature of most modern engines, as it allows for cylinders to be turned on and off on the fly. Because it interlinks closely with very complex engines, usually it works very well.

However, the first attempt at this was the infamous 8-6-4 by General Motors, which was years ahead of its time, but also years ahead of being feasible, as the engine would lag infuriatingly, suffer from loud clunks, clanks and bangs, and often lead to reliability issues.



A designed-by-committed collaboration between Peugeot, Renault and Volvo in the 1980s, the engine was exceptionally slow, would frequently warp due to being made out of aluminium and often needed to be replaced entirely rather than repaired.

Most infamously, it was the engine that would be used in the disastrous-yet-iconic Delorean.

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