Informational Guide

How To Change Spark Plugs

By doing your own spark plug replacement, you save time & money. Learn how to change spark plugs with ease here.

The spark plugs in your car's engine are essential for reliable performance. These vital ignition system parts must be replaced regularly to protect your engine. By doing your own spark plug replacement, you save time and money. We will show you how to change spark plugs with ease.

It's not just important to know how to change spark plugs and wires, but you want to understand why. When you change the spark plugs, you help the engine to run better. While spark plugs don't necessarily increase horsepower, they do help optimize the engine, which can, in turn, produce more horsepower. When the motor is running as it should, you will also notice better fuel economy and smoother starts.

Changing spark plugs is considered a maintenance task that must be performed to protect the other engine components. If you aren't changing the spark plugs, you could notice performance issues, and the engine might not start. Plus, fouled or contaminated plugs lead to catalytic converter damage, which can be an expensive repair.

Do you know how often to change spark plugs? If you follow the recommended maintenance schedule outlined in the owner's manual of your vehicle, you can't go wrong.

When to Change Spark Plugs: Symptoms & Signs

As you wonder - how often do you need to change spark plugs – you will first reference your owner's manual and follow those guidelines. Aside from that, there might be signs that you need to change your spark plugs more often. Once you've figured out how often do spark plugs need to be changed, it's also important to look for these tell-tale signs that something is wrong.

  • Check Engine Light Illuminates – while this doesn't automatically point to faulty spark plugs, you want to consider it.
  • Trouble Starting Car – the spark plugs are a vital part of the ignition system.
  • Increased Gas Consumption – as the engine runs poorly, it will burn more fuel.
  • Rough Engine Idle – when the spark plugs are fouled, the engine can't run properly.
  • Car Doesn't Accelerate Quickly – until you optimize the engine, it will struggle to perform.
spark plug

How To Change Spark Plugs: DIY Steps

We can provide generic instructions on how to change spark plugs in a car, but you want to follow the advice given by the vehicle manufacturer as all vehicles are different. Reference your owner's manual for this information and to learn how to change spark plug wires.

Supplies Needed:

  1. 1
    Prepare your area. Park on a flat, dry surface and wait for the engine to cool off. Remove any dirt or debris from the area, so nothing falls into the engine cylinder. Disconnect the battery by removing the negative connection first. It also helps to have all of your tools and equipment nearby.
  2. 2
    Remove the spark plug wire. You may need to remove an engine cover or other parts to access the wires and plugs. As you take the wire off, use caution not to damage it. If the boot is stuck, use your pliers for support. Only work with one plug and wire at a time, so you don't get the sequence mixed up.
  3. 3
    Remove the coil on the plug (COP). The COP coils are attached to the spark plug end with an insulator boot. Disconnect the connector from the coil. You may need to push down or pull up on the tab that locks it in place.
  4. 4
    Unscrew the spark plug. Use your socket to remove the plug. To avoid thread damage, blow compressed air into the spark plug well hole with a COP application. If damage does occur, you can use a spark plug thread restorer tool to restore any damaged threads in the cylinder head. To remove seized or stubborn plugs, loosen it the best you can by turning it counter-clockwise a half a turn. Spray the lubricant into the thread area. Allow it to soak for a few minutes before attempting to remove the plug.
  5. 5
    Install the new plug. Make sure you use the correct plug for the cylinder head. Check the gap and give it a quick inspection.
  6. 6
    Reinstall the wires or COP. It's time to put the system back together the way you found it. Be careful not to cause any damage during installation.
  7. 7
    Test drive the vehicle. Reconnect the battery and start your engine to see how it runs.

For more in-depth information, you might find this YouTube video to be helpful.

Changing Spark Plugs of Different Vehicles: Expert Tips

Changing Spark Plug of a Lawn Mower

To learn how to change a spark plug on a lawn mower, you don't need many more skills than working with a regular vehicle, other than this job might be even easier. Follow the same steps you did with your vehicle, expect you probably won't have as many spark plugs to replace.

Changing Spark Plugs of Ford F150 4.6 L Engine

Learning how to change spark plugs on a Ford F150 4.6 L engine can seem daunting, but it doesn't have to be. Accessing the spark plugs on your truck is the most challenging part because you won't be able to get a good look at them. The plugs are located below the ignition coils, allowing them to be accessed through a hole in the cylinder. You will likely need an extension to get to some of your spark plugs.

People Also Ask (FAQs)

Is it easy to change spark plugs?

When you investigate how much is it to change spark plugs, you might decide to save money and do it on your own. With most vehicles, spark plug replacement is simple and can be done with a few tools. However, a few vehicles can make the process more difficult, especially if it is hard to get to the spark plugs.

Does changing spark plugs make a difference?

It will do no good to change out good spark plugs, but once they are worn and old, you will notice a difference in performance by installing new spark plugs.

How much does it cost to change spark plugs if you take it to a pro mechanic?

When you ask - how much does it cost to get spark plugs changed, you have two factors to consider. First, you have to figure the cost of the parts, which can range from $4 to $25 a spark plug, on average. Then, you need to know how much to change spark plugs based on what your mechanic charges per hour. Some vehicles are simple and only take an hour, while others can be more complicated.

How long does it take to change spark plugs?

If you want to do the job yourself, you might wonder how long to change spark plugs. If the process is straightforward, you can see all the plugs, and none are stuck, it shouldn't take you more than an hour. However, not all applications are this simple.

How often do you need to change spark plugs? Do you need to replace all spark plugs?

You should always reference the owner's manual to figure out how to know when to change spark plugs. Some will last up to 100,000 miles. You should also look at how often to change spark plug wires for a complete tune-up.

What happens if you don't change your spark plugs?

If the spark plugs foul out, you could notice trouble with the idling or the engine might stall completely. It will also cause the vehicle to burn more fuel and run poorly overall. If this condition persists, the engine might stop working altogether or you could ruin the catalytic converter, which is an expensive repair.

How long will spark plugs last?

Many people want to know how many miles to change spark plugs, but this depends on what type of plug you purchase. Some will last 100,000 miles, allowing you to perform tune-ups less frequently.


Keep your engine running its best with a simple tune-up that includes spark plug replacement. With some simple mechanical skills, you can do it yourself and save some money. Follow our spark plug replacement guide to get started.