A rogue’s gallery comprised of products of lofty engineering ambition, clever marketing, and brave stabs at innovation, turned incredibly bad — coming up with a definitive list of the most deplorable, worst most car engines of all time is, at best, an exercise in subjectivity. Pardon the expression but truth is, some car engines are worse than others, whether by intent or accident.
In no particular order of notoriety, we enumerate some of the car engines widely acknowledged by car fans, aficionados and ardent followers as possibly among the worst ever in history.
Cadillac V8-6-4 and HT400
Even a casual internet search will prove that the Cadillac V8-6-4 is popular…. in the negative sense of the word. This appeared in numerous lists, a testament to the kind of ruckus it made when it made its appearance in 1981.
The Cadillac engineers have this noble idea of creating an engine capable of deactivating cylinders to achieve better fuel economy for the company’s heavy luxury cars. “Displacement on Demand” was an impressive term for the technology.
Driveability was the term used to explain what the tech caused – solenoids used by the hydraulic lifters were inconsistent and prone to failure. The lifters collapse and consequently, the cam lobe fails to open the valve. Resurrected sans the deactivation tech a year later, the engine proved to be a good one.
The Cadillac HT4100 was the company’s stab at making a lighter, 4.1L engine with cast iron cylinder heads. Power output is a paltry 135 horsepower. Most common problem: head gasket failures. Underpowered yet over problematic.
Mopar 2.2L I-4
This engine has earned a rather unique if rather disparaging distinction: “rod knocker”. The original 2.2L engine was already problematic when Mopar added turbo to it.
To further compound the problem, the engine found its way into the lineup of Chrysler automobiles, from full-size cars to the minivans; all suffered from the same fate. Like the Cadillac V8-6-4, the Mopar 2.2L turbo proved to be a solid performer after being rebuilt with aftermarket adds-on and other internal upgrades.
Vega 140 Overhead Cam and Cossworth Vega 4-cylinder
The first was produced from 1970-77 employing a design that looks more like a WWII vintage tractor motor.
Silicone-impregnated aluminum cylinders were used instead of cast iron sleeves; carburetor fire risks forced Chevy to recall 132,000 vehicles. The latter was a severely under-performing 2-liter, inline-four, 16-valve, EFI engine that coughs out just 110 horsepower.
Oldsmobile V8
Did diesel cars really have a shot at capturing the interest of American drivers and owners? Stash this under the “We’ll Never Really Know” category. General Motors had that chance in the 80s.
For the Oldsmobile V8, GM shaved development costs by transforming gasoline engines instead of a turbo-diesel powertrain. The result: “the diesel debacle” making the Oldsmobile V8 a prime candidate for worst car engine of all time.
Not only was performance problematic at just 120 horsepower and 220 pound-feet of torque, leaky head gaskets, an aberrant fuel pump timing chain, and other defects were found to have the potential for catastrophic failures by the 30,000 mile mark.
Subaru 2.0 & 2.5L
Some cars are known as “gas guzzlers”. But Subaru can claim the distinction of having “oil guzzler” engines.
Its non-turbo 2.0 and 2.5L engines required a quart-sized top-off of synthetic oils every few thousand miles – a problem attributed to a defective piston ring and admitted by Subaru in 2016. Not surprising;y, a lawsuit followed.
Ford V6 and V8
From the inventor of the modern automobile comes a toss-up of two engines from different eras to be deemed worst engines of all time.
The first Ford Flathead V8 could’ve accelerated Americans into a new era of speedier transportation. Instead, its material and design flaws particularly in its intake manifolds, cooling system, and rear cylinders, kept it from rewriting history.
On the other hand, the Ford 2.8L V8 that powered Mustangs and Capris, suffered from cracked cylinder heads and noisy solid-lifter valvetrain. Even a pioneer can make mistakes, right?
Chevy 305 H.O. V8 and Eco-Tec 2.2 I-4
From the small engine block era of Chevy, the Chevy 305 H.O. V8 offers an abject lesson in making compromises. The engine is, essentially, little changed from those used in the company’s station wagons.
For a super high-performance engine, this one appeared in possession of mere mortal powers cursed with a small bore that made it under-perform well under its specs.
The Eco-Tec 2.2 was replaced by an all-new version for good reason. Used in the Cavalier, Beretta and some of the Chevy S-10 and S-15 pickups, the under-achieving engine had steel freeze plugs that suffer from corrosion, a potential catastrophe inducer past the 50,000 odometer reading.
