How Often Do Spark Plugs Need to Be Replaced?

For any car owner or DIYer, an engine tune-up is one of the most recognizable maintenance processes. But the interval for how often to change spark plugs has changed drastically over the decades. Until carbureted vehicles dwindled from production, it was common to replace these air-fuel igniters every year or 10,000 miles.

But technology has changed, and spark plugs last longer as engines are more precisely manufactured and higher quality materials are used. The average spark plug price is around $10 each, but how often should they be swapped out for new ones??

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How often should you change your spark plugs?

Spark plugs are an important component of your vehicle’s ignition system, and they can wear out over time. The frequency at which spark plugs need to be replaced can vary depending on the make and model of your vehicle, as well as the type of spark plugs that are being used.

Generally, spark plugs should be replaced every 30,000 to 100,000 miles, depending on the manufacturer’s recommendations for your specific vehicle. Some spark plugs may need to be replaced more frequently if they are subjected to extreme conditions, such as high temperatures or extended periods of idling. The ways that you should determine when your spark plugs need to be replaced can be broken down into two categories: recommended interval and wear.

According to wear

Spark plugs have a finite lifespan and will eventually wear out and need to be replaced. There are several factors that can contribute to the wear and tear of spark plugs, including:

  • Heat – Spark plugs can get extremely hot during operation, and over time, this heat can cause the electrodes to wear down or even melt.
  • Firing voltage – The high voltage required to create a spark can also cause wear and tear on the spark plugs over time.
  • Deposits – As spark plugs fire, they can create deposits on the electrodes and insulator. These deposits can build up over time and affect the performance of the spark plugs.
  • Vibration – The constant vibration of the engine can also contribute to the wear and tear of spark plugs, degrading or fracturing the insulator.

Signs of wear on spark plugs should compel you to change them right away so your vehicle’s performance and fuel economy don’t suffer.

According to time and mileage

So, how often should you change spark plugs? The preferred method to determine how often spark plugs should be changed is at a set interval. Each manufacturer has determined the timing when they should be swapped out and a new set installed. It depends on the type of spark plugs your engine uses as well as the estimated number of miles or years in operation that they can be expected to last.

Copper spark plugs need to be replaced the most often since the nickel alloy used wears down rather quickly. Platinum is much harder and can last much longer, and Iridium is even better at resisting normal wear. The newest type of spark plug, Ruthenium, is said to last the longest.

When to recognize your spark plug needs changing

Several symptoms may indicate that your spark plugs are worn out and need to be replaced:

  1. Reduced engine performance: Worn spark plugs may not be able to create a strong enough spark to ignite the fuel, which can lead to reduced engine performance and a decrease in power.
  1. Difficulty starting the engine: If the spark plugs are worn out, the engine may have difficulty starting or may not start at all. It could also stall unexpectedly.
  1. Poor fuel economy: Worn spark plugs can cause the engine to run inefficiently, which can lead to poor fuel economy.
  1. Misfiring engine: Spark plugs that are worn out or malfunctioning may cause the engine to misfire, which can result in a rough idle or jerking movement when driving.
  1. Check Engine Light: In some cases, a malfunctioning spark plug may trigger the Check Engine Light to turn on from misfire codes, catalytic converter inefficiency codes, or other performance-related DTCs.
  1. The maintenance reminder comes on. For some newer models, your instrument cluster will indicate that a major service is required, which typically includes changing the spark plugs.

If you are experiencing any of these symptoms, it is a good idea to check your spark plugs to determine if they need to be replaced.

What does spark plug replacement cost?

The cost to replace spark plugs can vary depending on a number of factors, including the make and model of your vehicle, the type of spark plugs being used, and where the spark plugs are being replaced.

On average, you can expect to pay anywhere from $3 to $30 for a single spark plug, with the majority of spark plugs falling in the $10 to $20 range. However, some high-performance spark plugs can cost significantly more.

Labor costs can also be a significant factor in the overall cost of spark plug replacement. Depending on the complexity of the job and the hourly rate of the mechanic, you can expect to pay anywhere from $50 to $200 in labor costs.

In total, you can expect to pay anywhere from $100 to $500 or more to have your spark plugs replaced, depending on the factors mentioned above. However, changing the spark plugs is often a job that’s doable by DIYers, saving you the cost of labor in exchange for an afternoon or evening working on your vehicle.

Whether you need to know how often to replace spark plugs for your car or you’re looking for the right parts, AutoZone can help. Ask an associate for Trustworthy Advice or filter online search results by year, make, model, and engine size for the best fitment. If the job is too big for you, seek out one of our Preferred Shops to help you do the job.

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FAQ/People Also Ask

How long do spark plugs last usually?

How long a set of spark plugs lasts depends on the vehicle you drive and the type of spark plugs it uses. Typically, expect between 30,000 and 100,000 miles of usage.

How do I know if my spark plugs need changing?

Keep track of your routine maintenance to determine if spark plugs are due for replacement. If you have a Check Engine Light on or performance-related symptoms, it could indicate a tune-up is necessary.

What happens if you don’t change the spark plugs?

Worn spark plugs contribute to an engine misfire, excessive fuel consumption, and loss of performance.

How much does it cost to replace a spark plug?

For a set of spark plugs on a common model, prices range greatly from around $100 to $500 or so. 

Can spark plugs last 200,000 miles?

The newest technology, Ruthenium spark plugs, are purported to last as long as 200,000 miles under ideal conditions.

Why is replacing spark plugs so expensive?

The higher-grade spark plugs contain precious metals that elevate the price. As well, the labor costs to replace spark plugs can really increase the price of replacement substantially.

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