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How Long Does An Alternator Last?

If you’re a car owner, you may have heard of an alternator but may not be entirely sure what it does or how long it lasts. In this article, we’ll dive into everything you need to know about alternators, including their average lifespan, factors that affect longevity, signs of a failing alternator, tips to extend its life, the importance of regular maintenance, common causes of failure, how to test if it’s working correctly, what to consider when replacing one, and choosing a high-quality alternator.


How Long Does An Alternator Last?

An alternator is an essential component of a car's electrical system, responsible for generating electricity to power various electronics and charging the battery while the car is running. The lifespan of an alternator can vary greatly depending on several factors, such as the make and model of the vehicle, driving conditions, and the quality of the alternator itself.

On average, a well-maintained alternator can last anywhere from 80,000 to 150,000 miles, which roughly translates to about seven years. However, some alternators may last much longer than that, while others may fail prematurely due to different reasons.

Factors Affecting The Longevity of An Alternator

Several factors can impact the lifespan of an alternator, some of which include:

Driving Conditions

Driving in extreme temperatures or harsh weather conditions, such as heavy rain or snow, can put extra strain on the alternator, causing it to wear out faster. Additionally, if you frequently drive short distances or use your car infrequently, the battery may not get enough time to recharge fully, causing the alternator to overwork and wear out faster.

Quality of the Alternator

The quality of the alternator plays a significant role in how long it lasts. Higher quality alternators generally have better components and are built to higher standards, making them more durable and longer-lasting than cheaper alternatives.

Electrical Load

Adding extra electrical load to your car, such as installing a high-powered stereo or aftermarket lights, can put additional strain on the alternator, causing it to wear out faster.


Regular maintenance is crucial to the longevity of an alternator. Neglecting basic maintenance, such as checking and replacing the drive belt or keeping the terminals clean and tight, can cause the alternator to fail prematurely.

Signs of a Failing Alternator

Knowing the signs of a failing alternator can help you catch any issues early and prevent further damage to your car's electrical system. Some common signs of a failing alternator include:

Dimming or Flickering Lights

If your headlights or interior lights start to dim or flicker while driving, it could be a sign that the alternator is struggling to keep up with the electrical demand.

Warning Light

Most modern cars have a warning light on the dashboard that indicates a problem with the charging system. If this light comes on, it's essential to get your car checked by a mechanic as soon as possible.

Strange Noises

A failing alternator may produce a rattling or whining sound, especially at idle or low speeds.

Dead Battery

If the battery dies frequently or struggles to hold a charge, it could be an indication that the alternator is not charging the battery correctly.

Electrical Issues

Other electrical issues, such as power windows or locks not working correctly, could also indicate a problem with the alternator.

Tips to Extend the Life of an Alternator

While some factors affecting the lifespan of an alternator are beyond our control, there are several things you can do to help extend its life:

Drive Consistently

Driving your car regularly helps keep the battery charged, reducing the strain on the alternator.

Reduce Electrical Load

Limiting the electrical load by removing unnecessary accessories or avoiding adding extra electrical components can help reduce the strain on the alternator.

Check the Battery

Keeping the battery in good condition, such as ensuring it's fully charged, can help reduce the strain on the alternator.

Regular Maintenance

Performing regular maintenance, such as checking and replacing the drive belt and keeping the terminals clean and tight, can help prevent premature alternator failure.

Avoid Extreme Conditions

Avoid driving in extreme temperatures or harsh weather conditions whenever possible to reduce the strain on the alternator.

Importance of Regular Maintenance for Alternators

Regular maintenance plays a critical role in ensuring the longevity of an alternator. Here are some essential maintenance tasks that can help keep your alternator running smoothly:

Check Drive Belt Tension

The drive belt connects the alternator to the engine and is responsible for turning the alternator rotor. Over time, the drive belt can stretch or wear out, causing it to slip and not turn the alternator correctly. Checking the drive belt tension regularly and replacing it if necessary can help prevent alternator failure.

Keep Terminals Clean and Tight

Battery terminals can corrode over time, which can cause electrical resistance and prevent the alternator from charging the battery correctly. Keeping the terminals clean and tight can help ensure proper electrical contact and reduce the risk of alternator failure.

Test the Charging System

Regularly testing the charging system, either with a voltmeter or by taking your car to a mechanic, can help detect any issues early before they cause more significant problems.

Common Causes of Alternator Failure

While alternators are generally reliable components, several factors can cause them to fail prematurely. Some common causes of alternator failure include:

Wear and Tear

Like any mechanical component, an alternator will eventually wear out over time due to normal use.


Adding too much electrical load, such as installing high-powered accessories, can overload the alternator, causing it to fail.


Excessive heat can cause the insulation around the alternator windings to break down, resulting in a short circuit that can damage the alternator.


Corrosion can build up on the alternator's terminals and connections, causing resistance that prevents it from charging the battery correctly.

How to Test if an Alternator is Working Properly

Testing an alternator is relatively straightforward and can be done using a voltmeter or taking your car to a mechanic. Here's how to test if your alternator is working correctly:

Using a Voltmeter

With the engine running, connect the voltmeter to the battery terminals. A healthy alternator should produce a voltage reading between 13.5 and 14.5 volts. If the reading is lower than this, the alternator may not be charging the battery correctly.

Taking Your Car to a Mechanic

If you're unsure how to use a voltmeter or prefer to have a professional do it, taking your car to a mechanic is always an option. They can perform a more comprehensive charging system test to determine if there are any issues with the alternator, battery, or other components.

Replacing an Alternator: What to Consider

When replacing an alternator, several factors should be considered to ensure you get the right one for your vehicle:


As mentioned earlier, the quality of the alternator can significantly impact its lifespan. Opting for a high-quality replacement alternator, such as those offered by reputable brands, can provide better reliability and longevity than cheaper alternatives.


It's essential to ensure that the replacement alternator is compatible with your vehicle's make and model, as well as any electrical accessories or modifications you may have installed.


Choosing an alternator with a warranty can provide peace of mind and protection against premature failure.

Alternator Warranty Information

Alternator warranties vary depending on the manufacturer and the type of alternator. It's essential to read the warranty information carefully before purchasing a new alternator to ensure you're getting adequate coverage. Some things to consider when looking at alternator warranties include:

Length of Warranty

The length of the warranty can vary from a few months to several years, depending on the manufacturer and type of alternator.


Make sure to read the warranty coverage carefully to understand what parts and labor are covered and under what circumstances.


Most warranties have conditions that must be met to be eligible for coverage, such as proper installation or maintenance.

Choosing a High-Quality Alternator

Choosing a high-quality alternator is crucial to ensuring its longevity and reliability. Here are some things toconsider when selecting a high-quality alternator:

Brand Reputation

Opting for a reputable brand with a proven track record of producing high-quality alternators can provide peace of mind and reliability.

Construction Quality

The construction quality of the alternator is essential to its longevity. Look for alternators with durable materials, such as copper windings, sturdy housing, and high-quality bearings.

Output Capacity

Make sure to choose an alternator with sufficient output capacity to meet your vehicle's electrical needs, especially if you have added extra electrical load.


While choosing a high-quality alternator may cost more upfront, it can save you money in the long run by avoiding premature failure and replacement costs.


In conclusion, while the lifespan of an alternator can vary greatly depending on several factors, regular maintenance, minimizing electrical load, and driving conditions can help extend its life. Knowing the signs of a failing alternator, testing it regularly, and considering high-quality replacements can also prevent further damage and costly repairs. Remember always to read the warranty information carefully before purchasing a new alternator to ensure adequate coverage. By taking these steps, you can keep your car's electrical system running smoothly for years to come.

About Jason Trevino

Jason is a talented and advanced author, blogger and auto expert. He is determined in researching thousands of products so as to make it easy for the owners to find the best products. He focuses on giving users better understanding on products they are using and ones they anticipate to buy.

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