Why Some Cars Are Still Using Parts That Mechanics Warned About Years Ago
Car technology keeps evolving, but oddly enough, some manufacturers continue using parts that mechanics have flagged as problematic for years. These aren’t minor components—they’re the kinds of unreliable car parts that can lead to breakdowns, costly repairs, or safety concerns. Whether it’s because of cost-cutting, supplier contracts, or outdated design philosophies, these parts are still showing up in vehicles on dealership lots. Mechanics have seen the consequences firsthand, and many are left wondering: why haven’t these parts been retired yet? If you’re shopping for a car or maintaining one, these 10 components are worth keeping an eye on.
1. Plastic Intake Manifolds That Warp Under Heat
Plastic might be lightweight and affordable, but it’s not always durable, especially under a hot engine hood. Several car models, especially in the early 2000s, used plastic intake manifolds that cracked or warped over time. Despite years of mechanical warnings, some manufacturers still install these in newer models. The result? Coolant leaks, rough idling, and sudden check engine lights. When it comes to unreliable car parts, this one continues to cause expensive surprises.
2. CVT Transmissions With a History of Failures
Continuously Variable Transmissions (CVTs) are designed to improve fuel efficiency and create a smoother ride. But early models—and even some recent ones—have been plagued with problems like slipping, overheating, and total failure before 100,000 miles. Nissan and other automakers have faced lawsuits and extended warranties because of CVT issues. Still, CVTs are used in many budget-friendly sedans and SUVs despite repeated mechanical concerns. These unreliable car parts can leave drivers stranded with costly repair bills.
3. Timing Belts Hidden Behind Expensive Labor
Many modern engines have switched to timing chains, which last longer and typically don’t require scheduled replacements. However, some automakers continue to use rubber timing belts that need to be replaced every 60,000 to 100,000 miles. The belt itself isn’t too expensive, but getting to it is, especially if it’s buried behind engine components. If it snaps, the damage to your engine can be catastrophic. Mechanics have long warned about the risk and maintenance cost of this unreliable car part.
4. Fragile Window Regulators That Keep Failing
You wouldn’t expect your car window to stop working just from regular use, but many owners have dealt with exactly that. Weak or poorly designed window regulators, especially in older Volkswagens, Jeeps, and BMWs, tend to break prematurely. You’re left with windows stuck down, noisy rattling, or glass that suddenly drops into the door. Incredibly, some newer models still use similar flawed designs. It’s one of those unreliable car parts that’s more annoying than dangerous, but still costly and inconvenient.
5. Oil-Consuming Engines That Just Won’t Quit
Some engines are known oil-burners—meaning they use more oil than they should between changes. Subaru, Audi, and BMW have all had models with this issue, and mechanics routinely advise customers to check their oil weekly. Despite customer complaints and legal settlements, some car brands continue to manufacture engines with this same flaw. Excessive oil consumption can lead to engine damage, reduced resale value, and frequent top-offs. It’s a classic case of unreliable car parts that persist due to design indifference.
6. Weak Suspension Bushings That Wear Out Fast
Suspension bushings are small rubber parts that absorb road vibrations and reduce noise. But in many models—especially certain Hondas, Chevys, and Fords—they wear out prematurely. Once they go, drivers often notice clunking noises, poor handling, and uneven tire wear. Mechanics have pointed this out for years, yet manufacturers continue using soft rubber bushings prone to cracking and tearing. When ignored, these unreliable car parts can turn into serious suspension problems.
7. Infotainment Systems That Glitch and Crash
Modern cars are loaded with touchscreen controls and complex infotainment systems. But not all of them are reliable. Some systems freeze, reboot randomly, or completely shut down—sometimes affecting rear cameras, navigation, or even climate controls. Jeep Uconnect, Ford MyTouch, and older Subaru STARLINK systems have all drawn criticism from mechanics and drivers alike. Even newer models still suffer glitches tied to these unreliable car parts, frustrating owners and complicating driving.
8. EGR Valves That Get Gunked Up
Exhaust Gas Recirculation (EGR) valves are designed to reduce emissions, but they’re notorious for clogging with carbon buildup. Mechanics frequently clean or replace them after drivers notice rough idling or engine hesitation. Despite being a common failure point, these valves remain a staple in many engines. Their placement and design often make them difficult to clean or reach. For a part so prone to failure, it’s one of the most stubbornly persistent unreliable car parts.
9. Starter Motors That Die Prematurely
A failing starter motor can leave you stranded in a parking lot with no warning. Some vehicles are more prone to starter issues due to poor placement, overheating, or electrical gremlins. Chrysler and Hyundai models have had recurring issues with early starter motor failure. Replacing the part isn’t cheap, especially if it’s buried beneath other engine components. Despite being a known issue, these unreliable car parts still pop up in many cars on the road today.
10. Headlight Assemblies That Fog and Yellow Quickly
It might not seem like a big deal, but foggy headlights affect visibility and safety. Many modern cars use plastic lens covers that degrade quickly due to sun exposure, leading to yellowing and hazy lights. Mechanics often warn owners about reduced lighting performance, but replacement assemblies can cost hundreds. Automakers have been slow to improve these designs, leaving consumers to deal with this ongoing, unreliable car part problem.
Why These Parts Keep Coming Back
So why do manufacturers keep using parts that mechanics clearly warn against? The answer is often a mix of cost, legacy designs, and consumer tolerance. Unless a part creates a widespread legal or safety issue, automakers may choose to stick with the status quo. But for informed buyers and car owners, knowledge is power. Understanding which unreliable car parts are still in circulation can help you avoid trouble before it starts.
Have any of these parts failed on you before? Drop your experience in the comments and let others know what to watch out for.
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