How to Change Spark Plugs in 5 Easy Steps

Anyone who drives a vehicle with a gasoline engine should understand the importance of spark plugs. These are the parts which create the spark that ignites the air and fuel mixture in the internal combustion chamber of the engine. What some may not realize is that spark plugs don’t last forever.

Each time a spark plug generates a spark, it wears down a little bit of the metal on its two electrodes. After a while, the electrodes will become so eroded that they won’t be able to provide the spark needed to ignite fuel in the combustion chamber.

This is when you will start experiencing symptoms of a faulty spark plug like engine misfires, decreased engine performance, increased emissions, and poor gas mileage.

In this article, we‘ll cover how to identify the type of spark plug you need, the tools necessary to replace spark plugs on your own, and the actual steps for doing so.

How Often Should You Replace Spark Plugs?

dirty spark plug

Most vehicles these days should have their spark plugs replaced every 80,000 to 100,000 miles. However, this will vary depending on the make and model of your vehicle.

To ensure that your spark plugs are replaced at the recommended interval, it is best to consult your vehicle‘s owner‘s manual.

Before You Start

In order to change your spark plugs, you‘ll need to identify the type of spark plug your car needs. Knowing the year, make, and model of your car will help you to determine the type of spark plug you need to buy. This information can typically be found in your owner‘s manual, your local dealership’s service department, auto parts store, or online. 

Before you can change your spark plugs, you‘ll also need to gather the necessary tools. You‘ll need a spark plug socket of the correct size, ratchet, extension, torque wrench, spark plug gap tool, spark plug boot puller, and possibly some antiseize lubricant.

Once you have the necessary tools, you‘ll need to disconnect the negative battery cable to prevent any accidental electrical shocks during the job.

How to Change the Spark Plugs

best spark plugs

Step 1) Remove the Spark Plug Wires

The first step is to remove the spark plug wires from the spark plugs. This can be done with a spark plug boot puller or a pair of needle nose pliers. You‘ll need to be careful not to pull on the wires too hard, as this can damage the connection.

Step 2) Remove the Old Spark Plugs

Once the wires are removed, you can then remove the old spark plugs. You‘ll need to use the spark plug socket to unscrew the old plugs from the engine. Make sure to keep track of the order of the spark plugs so that you can replace them in the correct order. If this is your first time, it’s best to replace the plugs one by one.

Step 3) Install the New Spark Plugs

Once the old spark plugs are removed, you can then replace them with the new spark plugs. Make sure to use the spark plug gap tool to check the gap of the new spark plugs according to what the manufacturer states in your car’s owner manual. If the gap is too small or too large, you‘ll need to adjust it accordingly.

Step 4) Reattach Spark Plug Wires

Once the new spark plugs are installed, you can then reattach the spark plug wires. Make sure to attach the wires in the correct order. This again is where replacing spark plugs one by one is safer even though it takes longer. Once the wires are secured, you can then move on to the next step.

Step 5) Reconnect the Negative Battery Cable

Once all of the spark plugs are installed, you can then reattach the negative battery cable. This will restore power to the car‘s electrical system. After that, you can start the car and check for proper operation.

If all of the spark plugs are functioning correctly, the car should start right up. Once the car is running, it‘s important to check for any signs of misfiring. If you notice any misfiring, you may need to go back and adjust the gap on the spark plugs.

Is a Special Tool Required to Change Spark Plugs?

No, you do not need a special tool to change spark plugs. The tools required above are fairly basic and most individuals who do basic car maintenance already own. A spark plug gap tool may be needed if the spark plugs you purchased are not already set to the correct gap but this tool can easily be found for under $5 at any place that sells auto parts.

What Can Happen if You Don’t Change Spark Plugs?

If you don’t change your spark plugs, it can lead to a number of engine performance issues. These issues can include reduced fuel efficiency, decreased engine performance, increased emissions, increased engine noise, difficulty starting the engine, and increased maintenance costs.


Spark plugs play an essential role in the operation of your car‘s engine. It‘s important to change your spark plugs regularly according to your car manufacturer’s recommended interval to ensure that your car is running smoothly and efficiently. Spark plug replacement is something almost anyone can do on their own. If you’ve ever changed your own oil, you will almost certainly have no issue changing your spark plugs.

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