When you buy a car, you expect it to be reliable, safe, and able to carry you confidently for thousands of miles. But sometimes, things go wrong — and not just small things like a faulty sensor or a rattling door panel.
In some unfortunate cases, cars come with engines that are prone to serious failure, leaving owners with repair bills that can feel like a gut punch.
In this guide, we break down four cars (or groups of cars) that have become known for major engine failures. We explain what went wrong, how manufacturers have responded, and what you should look out for — whether you already own one or are shopping for a used model.
Let us dive into the details.
1. Hyundai and Kia Vehicles with 2.4L Theta II Engines
Hyundai and Kia have been applauded for building affordable, well-equipped vehicles, but their 2.4L Theta II engine has cast a long shadow over their reputation.
You will find this engine in popular models like the Hyundai Sonata, Kia Optima, and Kia Sorento — and for some owners, it has been nothing short of a disaster.
What Went Wrong
The core issue was a manufacturing defect. Metal shavings left behind during the crankshaft machining process blocked vital oil passages, starving the engine of lubrication.
Without oil flow, parts like bearings and the crankshaft itself wore out rapidly, causing the engine to seize. In extreme cases, the engines caught fire — turning a mechanical problem into a full-blown safety hazard.
Consequences
Many drivers first noticed a knocking sound before the engine stopped running altogether. Unfortunately, an out-of-warranty engine replacement could cost $5,000 or more.
The scale of the problem, which affected over two million vehicles, also damaged Hyundai and Kia’s reputations as reliable brands.
Manufacturer’s Response
Both companies faced class action lawsuits and ultimately agreed to a settlement that offered free engine replacements for affected vehicles (spanning the 2011–2019 model years).
They also rolled out recalls and added a knock sensor update designed to detect impending failures. But with so many vehicles involved, repair times have often stretched on, leaving owners waiting.
What Owners Should Do
If you own or plan to buy a used Hyundai or Kia from this era, confirm whether the engine has been replaced or if it remains under warranty.
Use the VIN lookup tools to check for open recalls. And above all, keep up with oil changes and listen carefully for engine noise — it could be your early warning sign.
2. Toyota Tundra (2022–2023) with Twin-Turbo V6 Engine
Toyota has long been a gold standard for reliability, so when the 2022–2023 Toyota Tundra rolled out with a new twin-turbo V6 engine, many expected a smooth transition away from the old V8. Instead, some owners ran into serious trouble almost immediately.
What Went Wrong
Machining debris was left inside the engine during manufacturing, contaminating the oil system and damaging the bearings. This led to rapid wear and — in some cases — sudden engine failure while driving.
The issue did not just affect the Tundra; Toyota’s luxury sibling, the Lexus LX600, which shares the same engine, also saw failures.
Consequences
Toyota recalled over 100,000 vehicles after complaints started rolling in, with some engines failing with less than 10,000 miles on the odometer.
Unfortunately, repairs have been slow due to supply chain issues, and owners have faced long wait times for engine replacements. The resale market has also been affected, with some buyers now hesitant to trust these newer models.
Manufacturer’s Response
Toyota issued a formal recall to inspect and replace defective engines. Still, the pace of repairs has been frustratingly slow for many owners, and reports have surfaced of engines failing even after they were replaced.
What Owners Should Do
If you own a 2022–2023 Tundra or are considering buying one, ensure the vehicle has been checked under the recall program.
For newer production runs, verify with the dealer whether Toyota has addressed the manufacturing issue.
This situation is a reminder that even the most trusted brands can stumble, especially when launching new engine designs.
3. Chevrolet Tahoe and GMC Yukon with 6.2L V8 L87 Engine
The Chevrolet Tahoe and GMC Yukon are beloved full-size SUVs that offer comfort, power, and a commanding road presence.
But the 6.2L V8 L87 engine available in these models has left many owners frustrated — and for some, stranded.
What Went Wrong
The L87 engine has been prone to connecting rod bearing failures. This critical component is essential for engine operation, and when it fails, the results can be catastrophic. The root causes appear to be linked to manufacturing defects or inconsistent quality control.
Consequences
General Motors has issued recalls covering nearly 600,000 vehicles, including 2019–2024 Tahoe and Yukon models (and even some Cadillac Escalades).
Owners have complained of long repair timelines, with some waiting months for a replacement engine. Dealerships have also placed stop-sale orders on affected vehicles, further complicating matters for buyers and sellers alike.
Manufacturer’s Response
GM is replacing engines under warranty, but parts shortages and overwhelmed repair networks have made the process slow.
The National Highway Traffic Safety Administration (NHTSA) has opened an investigation to determine whether additional measures are needed.
What Owners Should Do
If you are considering a used Tahoe, Yukon, or Escalade from this period, check the service records and ensure all recall work has been done.
For those who already own one, monitor for symptoms like knocking sounds or low oil pressure, and get the vehicle checked immediately if you notice anything unusual.
4. Chevrolet Vehicles with 2.4L Ecotec Engine
Chevrolet’s 2.4L Ecotec engine is a workhorse that powered models like the Malibu, Equinox, and Cruze for years. While not as catastrophic as the other engines on this list, it has earned a reputation for frustrating owners with costly issues.
What Went Wrong
The most common failure point is the timing chain. If the chain stretches or breaks, it can cause severe internal damage.
Additionally, the engine’s direct injection design leads to carbon buildup over time, affecting performance. Some owners have also reported excessive oil consumption.
Consequences
While complete engine failure is less common, repairs can still be expensive. Timing chain replacements often cost $1,000 to $2,000, and carbon cleaning services are not cheap either. For owners outside warranty coverage, these repairs can be a financial strain.
Manufacturer’s Response
General Motors has not issued widespread recalls, but many repairs have been covered under warranty when issues occur within the coverage period.
GM recommends regular maintenance, including timely oil changes and high-quality synthetic oil, to help prevent problems.
What Owners Should Do
If you drive a Chevrolet with a 2.4L Ecotec engine, stay vigilant. Keep an eye on oil levels, listen for unusual noises, and follow the maintenance schedule closely.
For used buyers, reviewing the service history is essential to ensure that known problem areas have been addressed.