12 Car Engines That Earned a Place in the Hall of Shame
The average car engine should last up to 150,000 miles, and with newer vehicles, that number rises to 200,000 miles. Yet some engines barely limp past 50,000 miles before failure happens.
After speaking to veteran mechanics and browsing NHTSA complaints, I discovered problematic engines that technicians would refuse to work on. Some of these failures were so predictable that repair shops could estimate the mile when these engines would break down.
Each engine on this list deserves its place with stains such as class-action settlements, manufacturer service bulletins, or widespread failure. We sourced data from technical service bulletins and NHTSA complaints, as well as verified repair records.
Cadillac V8-6-4
The V8-6-4 was Cadillac's failed attempt to make its large cars more efficient. A then-new engine management system was supposed to deactivate some cylinders when unused. However, the onboard computer was too slow to handle all the variables.
The battle between the software and the hardware became a nightmare for Cadillac owners. From vacuum leaks to oil pressure problems, the engine proved a stumbling mess. As a result, the V8-6-4 was Cadillac's standard engine for only one model year. While the general concept was sound, the execution was disappointing and perhaps too futuristic.
Jeep 2.5L I4
From 1983 to 2002, Jeep's 2.5-liter I4 powered numerous Wranglers and Cherokees. In its final form, the powerplant produced a pathetic 120 hp, barely enough to haul Jeep's heavy vehicles.
Owners frequently reported the engine's notorious oil leaks caused by a poorly designed valve cover gasket and oil pan seal. While the engine received accolades for its simplistic design, its poor output meant owners had to constantly drive at high RPMs to maintain highway speeds.
Chevrolet 2.2L Ecotec
In the 2000s, the Chevrolet 2.2L Ecotec was the engine of choice for a range of GM cars, including Chevrolet, Oldsmobile, and Pontiac. Owners had to deal with repair bills and headaches.
The most notable issues were caused by the engine's timing chain deteriorating prematurely, leading to chain slack and total engine failure. Head gasket failure was also common. And to make matters worse, the aluminum block design jacked up repair costs. Although GM tried to address these issues in later iterations, the 2.2L Ecotec's reputation had permanently tanked.
Mazda 1.3L Rotary
The Mazda 1.3L Rotary engine used in the RX-8 won International Engine of the Year on its debut in 2003. However, its brilliant engineering covered flaws that earned the engine a spot in the hall of shame.
Oil consumption was the powerplant's major shortcoming. While rotary engines burn oil by design, the RX-8 had an unhealthy appetite. Owners routinely had to check oil levels ever so often, and many engines failed when oil ran low. Hot starts were also common, as many drivers had difficulties restarting their cars after short drives. It got so bad that Mazda had to issue a technical service bulletin.
Subaru EJ25
The EJ25 arrived in 1996 and powered countless Imprezas, Outbacks, and Foresters. With this 2.5-liter boxer engine, head gasket replacement became a rite of passage for Subaru owners.
The core issue was Subaru's questionable decision to use a multi-layer steel head gasket with inadequate cooling passages. Combined with the boxer engine's inherent design, which places the head gaskets at the sides rather than the top, these gaskets would inevitably fail. External oil leaks from the valve covers and cam carriers became another EJ25 trademark.
Dodge 2.0L/2.4L SOHC Neon
Chrysler's 2.0L and 2.4L SOHC engines, found in the Dodge Neon and various Chrysler platforms, started as promising compact car engines but quickly derailed. The engine's timing belt system became its defining weakness.
While most manufacturers recommended belt changes at 100,000 miles, these engines often saw belt failures at 60,000 miles or less. Oil sludging was also common, even with religious maintenance. The valve seals got bad prematurely, leading to excessive oil consumption, and head gaskets were included in the failure party.
Volkswagen 1.8T
Volkswagen's 1.8T engine was in the VW-Audi lineup from 1997 to 2000. Its appetite for oil was legendary, as was its ability to hide consumption until it was too late. The poorly designed PCV system would clog, causing excessive crankcase pressure and oil leaks from every seal and gasket.
Other problems included sludge buildup and ignition coil pack failure. Owners also complained of components failing in the 1.8T, including the water pump, coolant temperature sensor, and timing belt/tensioner.
Oldsmobile Diesel V8
This was an ill-fated attempt by Oldsmobile to improve the efficiency of its large cars. Instead, it ended up with a loud and underpowered motor that belched black smoke.
Moreover, the diesel V8 has developed several reliability issues. Blown head gaskets let coolant leak into the cylinders and caused serious engine damage. Not only did the Diesel V8 land General Motors with a class-action lawsuit, but it also birthed the lemon laws.
Yugo 1.1L I4
Arriving under the hood of the Yugo 55, the Yugo 1.1L I4 became a hit for the wrong reasons. The engine only cranked out 55 hp, and owners had to constantly adjust the single-barrel Weber carburetor.
The timing belt also needed to be replaced every 40,000 miles; otherwise, it could snap and destroy the engine. Besides that, the Yugo 1.1L I4 also failed to meet the emissions standards of the day.
Saab 2.8L V6 Turbo
On paper, the Saab 2.8L Turbo looked like a promising engine. It combined Saab's turbocharging know-how with GM-derived architecture, but that marriage only produced an underwhelming engine.
The engine was synonymous with oil sludge buildup, particularly in the turbocharger oil feed lines. Even worse was the engine's appetite for fuel pump modules, which would fail without warning, stranding owners. The plastic intake manifold was prone to warping and cracking, especially in hot climates. To compound matters, the complex twin-scroll turbocharger system was susceptible to any deviation in maintenance schedules, leading to expensive repairs.
Pontiac 2.5L Iron Duke
The Iron Duke arrived in the late 1970s in response to the oil crisis. As the motor of choice for GM's compact car lineup, the 2.5L Iron Duke delivered a measly 90 hp. This was barely enough to motivate lightweight models like the Pontiac Fiero, earning it the nickname “Iron Puke.”
The engine's carburetor was problematic, requiring frequent adjustments and rebuilds. Oil leaks were as common as blown head gaskets, especially in the Fiero. However, these differed from Iron Duke's poor timing chain design, which would stretch and eventually jump timing, leading to valve damage.
Triumph Stag V8
By twinning their existing I-4 engine, Triumph's engineers created a V8 engine that eventually ruined itself and the Stag. Common problems with the Stag V8 include main bearings that failed regularly and a timing chain that needed frequent replacement. Installing head studs at two angles made repairs difficult when the engine overheated.
Another red flag was the cooling system's inability to maintain proper operating temperature. The aluminum heads would warp at the slightest provocation, leading to blown head gaskets and overheating issues.
