How Many Miles Can a Car Last? (What Makes a Car Reliable)

Your car is one of the most expensive purchases you will ever make, and chances are you hope to keep it in good running order for a long time. So, exactly how long should you expect your car to last?

The answer is actually a bit complicated. Some vehicles seem to fail spectacularly right after the warranty ends. Others have traveled over 1 million miles with relatively little maintenance!

The difference between a reliable car and an unreliable one usually boils down to three properties: cost, design, and testing.

Car Life Expectancy Factors

Cost

It’s possible to build a vehicle that can survive the blast of a landmine and keep on driving, but few people would be able to afford it.

Automotive design has never been harder than it is now. Emissions and safety regulations are strict across the globe, yet they vary by region. Automotive engineers must balance the requests of consumers with the constraints of each region, all while keeping the product affordable to the target market.

This is why some really cool cars are only offered in Europe, Japan, or Australia, even when they’d probably sell very well in the United States.

Design

Most manufacturers design a vehicle with an expected service life. For example, maintenance intervals are specified up to 120,000 miles. After this point, the engineering team considers the vehicle to have reached its end of life (EOL).

The service life of a vehicle is a target lifespan. The engineering team determines this lifespan as part of the project scope and requirements. This information is not public, but may be inferred by reading the owner’s manual and factory service manual.

vehicle maintenance schedule
Sample car maintenance schedule

This target lifespan isn’t a simple trick to get you to buy more cars. Vehicles are built to a price point for a target market.

Overengineering components will raise the cost of the final product and would likely render it unaffordable to those who are most likely to buy it. It will also increase the cost of maintenance, since robust parts are more expensive. 

Once you pass the service life a vehicle was designed for, you’re usually in untested territory. Parts without a specified maintenance interval will start to break down, such as ignition coils, transmissions, and ECUs.

You can still keep driving past the car’s life expectancy, but be aware that maintenance costs will increase dramatically. Nearly every part becomes a wear item given sufficient time.

It may be up to you to determine the proper maintenance intervals for your car based on your specific driving conditions, the experiences of other owners, and perhaps the recommendations of a trusted mechanic.

Testing

The longer a product is tested, the more flaws are uncovered. Products with a long lifecycle tend to be most reliable near the end of that lifecycle due to testing and iteration on the original design.

Manufacturers put new cars through rigorous testing, yet no matter how much they test, they can’t account for every possible situation a consumer may encounter in the real world.

When a problem is discovered after a car is sold, the manufacturer may create a technical service bulletin (TSB) to address a common customer complaint. The TSB specifies a recommended repair for dealership technicians. Engineers may address the concern in subsequent model years by using a revised part.

technical service bulletin (TSB)
Sample technical service bulletin

If the flaw is a serious safety hazard, manufacturers will usually issue a recall to fix the problem at no cost to the consumer.

3 Signs Your Car is Reliable

1) Late Model Year of the Generation

Honda Civic

Despite their best efforts to provide customers with a trouble free service life, new generations often come with unforeseen quirks and issues. Later model years have been tested more extensively and tend to be the most refined.

Even if the vehicle never had any major reliability issues, you’ll notice the later model years typically have better styling, more efficient engines, and reduced noise, vibration, and harshness levels (NVH).

2) Good Reviews

Lexus LS400
Credit: Consumer Reports

Manufacturers are not required to provide public data on issues that roll into the dealership, but you can get a pretty good idea on which cars are reliable by browsing online sources such as Consumer Reports.

For instance, Honda reliability was excellent in the 90s and 2000s, but has seen a few more complaints in recent years. Manufacturing defects can happen with any model, but if you see a very low number of complaints, chances are the car you’re looking at will do pretty well for many miles.

If you have a car in mind that you’d like to buy, ask around on forums to see what their experiences are. Car forums are a good way to hear from enthusiast owners who sometimes know almost as much about the car as the original manufacturer.

3) High Mileage, Low Maintenance

oil dipstick

If you know of a vehicle that can make it to 100,000 miles with nothing but regular maintenance, you’re probably looking at a very robust car.

When Toyota reliability comes up in conversation, people often joke that a Toyota isn’t even broken in at 100,000 miles. This large Japanese company invented lean manufacturing, a production strategy that has been copied by many manufacturers around the world, even those outside the automotive industry.

Some vehicles are intentionally overbuilt so they will last a very long time. The first generation Lexus LS 400 is a fantastic example of this.

The LS 400 launched with the Lexus brand in 1989 as Toyota’s introduction into the luxury market. Lexus needed to produce an excellent all around vehicle in order to survive against its German luxury competition. Much of Lexus’ success as a brand can be attributed to their very first well-engineered machine.

3 Signs Your Car is Unreliable

1) Neglected Maintenance

oil in spark plug well

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

electrical problems

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

bad piston ring symptoms

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.

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