The powerplant of every combustion vehicle on Earth is its engine, and the successful longevity of any engine is the most key factor in any car's reliability in the long-term.
However, automotive manufacturers haven't always exactly been right when they've crafted these power plants, sometimes leading to dastardly results pre and even post-production. Listed here are the 10 most legendarily unreliable engine configurations ever put into production cars.
10 Cadillac V8-6-4
In the early 1980s, the folks at Cadillac wanted to test new technology in their vehicles, cylinder deactivation. Although this type of feature is commonplace in many cars today looking to up fuel economy, the idea was fairly new back then. The results of this early experiment were not fruitful at all, to say the least.
The motor’s unique hydraulic lifters were managed by solenoids that were always failing, thus when they could not engage themselves how they should, the lifters were prone to collapse. On top of this, valves couldn’t do their job very well either. This deadly harmony created a major issue for the V8-6-4, which was consistent throttle hesitation.
9 Mitsubishi 3-Cylinder
Probably the most underpowered engine in modern automotive technology, the barely 80 horsepower, three cylinders is a dangerous engine that makes simple tasks such as passing someone a fight for life. The engine is loud too, creating a disgusting racket that can be heard loudly throughout the tiny Mirage's interior.
8 Mopar 2.2-liter
One of the most commonly used Dodge engines in the 1980s had one of the most deadly issues a combustion engine could face constantly occur to it, rod knock. Powering everything from sports cars to minivans, the 2.2 was terribly unreliable and it took countless examples being produced before Dodge realized that the main issue was a lack of forged internals, which when implemented cleared the problems of the engine right up. Sadly, it took the entire run of the 2.2 engine to come and go before that realization, leaving it as one of the 20th century's most unreliable power plants.
7 Oldsmobile V8 Diesel
The engine configuration that is largely considered to be one of the main reasons Americans were largely turned off to the prospect of diesel engines, the Oldsmobile diesel V8 is a cautionary tale in terms of making sure to take the extra time and monetary investment to create a solid product before putting thousands of them on the roads and seeing what happens.
Oldsmobile, at the time, opted to convert normal gasoline engines to diesel to utilize in their new diesel cars as opposed to outright engineering a diesel platform. This cost-cutting measure resulted in thousands of failing engines that were prone to trouble from the beginning.
6 Lexus 2.5 V6
Probably one of the lowest-rated V6 engines of the modern day and age, the Lexus V6 that was formerly in the IS250 is the most lackluster engine configuration to probably ever come out of Toyota design. Creating a measly 200 horsepower that was largely restricted due to emission standards and the outstanding weight of the vehicle itself, the car is inherently a slouch.
Lexus attempted to validate the car's existence through generous interior appointments, but no level of features could make up for the sloth speed engine that was pulling a literal elephant of a car around every day.
5 Chevrolet 2.2 Liter Ecotec
Although the newer generation of this model has no real outstanding issues, it is older vehicles equipped with the 2.2 that buyers should be wary of. Despite a lack of power, the main issue in the 2.2 is corrosion, which can actually begin to happen to this engine and its supplemental parts as early as 50,000 miles into its existence. Such an easily fixable flaw that can clearly be attributed mostly to quality control issues is why this Chevrolet engine receives the place it does on this list.
4 Ford's First V8
Although Ford has become legendary for the reliability and power that its V8 power plants produce, that actually was not always the case. In fact, the first V8 engine Ford implemented was one of the least reliable engine configurations in modern automotive history. Piston rings on the engine were not made robustly enough to handle the engine, so they were prone to leaking oil that would cause seizing if untended. The rear two cylinders of the car also never ran as hard as the front six, leaving the engine largely unbalanced. Water pumps went frequently, and owners of cars sporting this engine reported going through a quart of oil for every one hundred miles driven, an absolutely abysmal statistic
3 Jaguar V12
Let's face it, Jaguar has never been one to be known wholly for reliability, but the V12 that it produced is perhaps the most unreliable of the bunch. A massive engine usually stuffed into bays not fully equipped for its size, the V12 was prone to failure and would even cause other systems in the car to break.
The lack of space in the engine bay led to electrical wiring becoming too hot from the heat of the engine and fraying, causing the electrical systems to go down. There was also a hosing issue, as in the Jaguar had way too many of them, often causing untended hoses to develop leaks or simply come apart from their intended position.
2 Subaru Boxer
The problem in modern Subaru cars now isn't necessarily rod-knock as it has been for two decades unless that is you purchase a current-gen WRX STI, which then it may be an issue. No, the issue today in modern Subaru boxers is the outrageous amount of oil they require. Originally toted as just a "Subaru thing," the issue is understandable somewhat in older motors, but to have to change your car's oil completely roughly every 3,000 miles because otherwise it will destroy the engine is a serious problem that Subaru did not address until brought to court, where they then had to issue a recall for models leading up to even the 2015 year that exhibited such issues...
1 Yugo 55
The little Serbian Yugo 55 is perhaps one of the most troublesome cars ever sold on American soil. With only 55 horsepower and size only slightly bigger than the benchmark tiny car, the BMW Isetta, it was doomed from the start.
On top of this, poor quality control and functionality of the small engine led to necessary timing belt changes every 40,000 miles, an issue completely foreign to all cars today.