How Many Miles Can a Car Last? (What Makes a Car Reliable)
Your car is one of the most expensive purchases you’ll ever make, and you probably want it to stay in good condition for a long time. So how long should you expect your car to last?
The answer is actually a bit complicated. Some vehicles seem to suffer major breakdowns shortly after the warranty expires. Some have driven over a million miles with relatively little maintenance.
The difference between a reliable and unreliable car usually boils down to three characteristics: cost, design, and testing.
Factors that Affect Car Life Expectancy
It is possible to build a vehicle that can survive a mine explosion and keep driving, but few people could afford it.
Designing a car has never been more difficult than it is today. Emissions and safety regulations are strict globally but vary by region. Automotive engineers must balance consumer desires with local restrictions while ensuring that their products are affordable for their target markets. This is why a really cool car might sell very well in the US, but only be offered in Europe, Japan, or Australia.
Design
Most manufacturers design their vehicles with an expected useful life in mind. For example, maintenance intervals are set to a maximum of 120,000 miles. After this point, the development team considers the vehicle to have reached its end of life (EOL).
The life of the vehicle is the target life. The development team determines this useful life as part of the project scope and requirements. This information is not publicly available, but can be obtained by reading the user manual and factory maintenance manual.
This target useful life is not a simple trick to get people to buy more cars; vehicles are built at a price that is tailored to their target market.
Components that are too large will raise the cost of the final product, potentially making it out of reach for most potential buyers. Maintenance costs also increase, because robust parts are expensive.
Once you exceed the designed service life of your vehicle, you usually enter uncharted territory. Parts that do not have specified maintenance intervals, such as ignition coils, transmissions, and control units, will begin to fail.
You can drive your car beyond its expected lifespan, but be aware that maintenance costs will increase significantly. Nearly all parts become wear parts over time.
It’s up to you to determine the correct maintenance intervals for your car, based on your specific driving conditions, the experience of other owners, and perhaps the recommendations of a trusted mechanic.
Testing
The longer a product is tested, the more defects are found. Products with long life cycles are the most reliable at the end of their life cycles because the original design has been tested and repeated.
Manufacturers put new cars through rigorous testing, but no matter how much testing they do, they can’t account for all situations consumers may encounter in the real world.
If problems are discovered after the car is sold, the manufacturer may issue a Technical Service Bulletin (TSB) to address common customer complaints. The TSB provides dealership technicians with recommended repairs. Engineers may fix the problem in subsequent model years by using redesigned parts.
Example of a Technical Service Bulletin
If the defect poses a serious safety hazard, the manufacturer will usually issue a recall to fix the problem at no cost to the consumer.
Three Signs Your Car is Reliable
1) Late Model Year
Despite efforts to provide customers with a hassle-free lifespan, new generations often come with unexpected quirks and problems. Late models have been more extensively tested and are generally the most refined.
Even if the vehicle has never had major reliability issues, you will find that later models tend to have better designs, more efficient engines, and lower noise, vibration, and harshness (NVH) levels.
2) Good Reviews
Manufacturers aren’t required to provide public data on problems they’ve had at their dealerships, but you can get a pretty good idea of which cars are reliable by searching online sources like Consumer Reports.
For example, Honda had great reliability in the ’90s and 2000s, but has seen a few more complaints in recent years. Manufacturing defects can happen with any model, but if the number of complaints is very low, there’s a good chance the car you’re considering will last many miles without any issues.
If you’re interested in a car you want to buy, ask on the forums what kind of experiences people have had with it. Auto forums are a great way to hear from enthusiastic owners who know almost as much about their cars as the original manufacturer does.
3) High mileage and low maintenance
If you know a vehicle that can go 100,000 miles with only regular maintenance, you’re probably dealing with a very tough vehicle.
When Toyota reliability is discussed, people often joke that Toyotas can go 100,000 miles without even breaking them in. This Japanese giant invented lean manufacturing, a production strategy that has been imitated by many manufacturers around the world, including those outside the automotive industry.
Some vehicles are intentionally oversized to last a long time. The original Lexus LS 400 is a great example. The LS 400 was introduced in 1989 under the Lexus brand as Toyota’s entry into the luxury car market. To survive in the German luxury market, Lexus needed to produce a good all-around car. Much of Lexus’ success as a brand can be attributed to its first well-designed machines.
3 Signs Your Car is Unreliable
1) Neglected Maintenance
Even a reliable car that has been neglected will eventually break down. If you’re shopping for a car, ask for the vehicle’s maintenance history before you make your purchase. Be prepared to play an expensive game of catch-up if the history is unknown.
You can often get a picture of an owner’s maintenance habits by the way they care for the interior and exterior of the vehicle. If the paint is shiny and the interior tidy, it’s a safe bet they took the time to take care of the mechanical bits as well.
2) Persistent Electrical Issues
Assuming your car hasn’t been in a flood, persistent electrical issues are often a sign that your car is unreliable.
You may be able to solve some electrical issues by simply cleaning or tightening ground straps or battery terminals. Others require a much more involved diagnostic process, and the root cause is simply poor design.
Higher mileage German cars are notorious for having less than stellar electrical systems. They may end up with all sorts of gremlins as they age.
Some electrical issues come with the added complexity you find on luxury vehicles. While complexity isn’t inherently a bad thing, a system with unnecessary complexity will have more points of failure.
3) Critical Powertrain Failure
Nobody likes to hear the words “blown head gasket”, “new transmission”, or “bad piston rings” from their trusted mechanic. While many failures are due to neglected maintenance, some are a result of bad design.
Engines and transmissions should not fail on low mileage cars that are driven and maintained responsibly.
Naturally aspirated Subarus from the late 90s and early 2000s are notorious for failed head gaskets. The problem can even happen as early as 80,000 miles. Do a little research before buying one of these, and make sure the head gaskets were repaired properly.
Conclusion
The average life of a car is hard to quantify, since there are many factors that determine longevity. Whether you’re buying a car or thinking about ditching one you already own, consider the tradeoffs of your potential purchase.
New cars have a warranty and are often safer. However, they are far more expensive than sticking with what you already have. Sometimes the manufacturer rushes to market without working out all the bugs, so issues can pop up even on a brand new vehicle.
A well cared for vehicle will run for many miles. Deferred maintenance will pile up very quickly if it isn’t. If you’ve accrued a bunch of maintenance debt on a clunker, it may be better to cut your losses and send it to the scrap yard, then put the money you’ve saved toward a down payment on something more reliable.