How to Remove a Seized Spark Plug in 5 Easy Steps

Sparks and gadgets may ignite excitement, but when it comes to spark plugs, a seizure can be discouraging. Refusing to release its grip on the cylinder head, a seized spark plug seems like the end of the road – and the end of your vehicle’s electrical system. But all hope is not lost!

While the process of removing a seized spark plug requires perseverance, patience and skill, you can easily keep your engine running with these 5 easy and practical steps. So, grab your tools and let’s jump in – and learn how to remove a seized spark plug in 5 easy steps!

Quick Recap of Key Points

You can use penetrating oil and an adjustable wrench or socket wrench to loosen the seized spark plug. If the spark plug is still stuck, you may need to use a special spark plug removal tool.

What Causes a Seized Spark Plug?

A spark plug that is stuck, or “seized”, in the cylinder head of an engine can cause a major frustration. There are several potential causes for a seized spark plug, but most often the culprit is corrosion caused by moisture and oil. This corrosion builds up and prevents proper lubrication of the spark plug threads which can then cause seizing. Additionally, this scenario is more likely to happen when a vehicle hasn’t been regularly maintained and therefore has inadequate lubrication or cleaning of the plugs.

It should be noted, however, that some prefer to argue that poor installation of the spark plugs can lead to seizing as well – most notably, if the plug was improperly tightened by hand or with a tool set to an improper torque setting. While this point may be valid it is generally accepted that moisture and oil build-up are the primary causes for seized plugs rather than an incorrect installation method.

Now that we have discussed the possible causes for a seized spark plug, it’s time to prepare ourself to remove the seized plug from the cylinder head.

Preparing to Remove the Plug

Before removing a seized spark plug, it is important to take the necessary steps to adequately prepare for the job. The first step is to determine the condition of the spark plug—if it is actually seized. Although there are many signs that can indicate a bad spark plug, such as black smoke from the exhaust or a check engine light, another way to narrow down the possibility of a seized spark plug is by listening as the engine runs. If the vehicle has a misfire, then this could point to a seized spark plug.

Next, make sure to wear protective clothing and eye-wear, such as gloves and googles. It is also important to have a few tools on-hand specifically for the task including an appropriately sized socket wrench, an extension bar, and a spark plug socket with rubber insert included. Some experts argue that using an impact gun (air wrench) can help break stuck plugs loose faster and easier. However, others suggest that this can strip the head of the plug, so caution should be taken when deciding whether or not to use one for this purpose.

Some ceramic spark plugs may shatter during removal, so surrounding any possible debris with foil before proceeding can help avoid messes. Additionally, it is important to note that some vehicles may require special tools specific to their model year when seizing spark plugs. Make sure to double-check your manual or consult with an automobile professional if you are uncertain what tools are required ahead of time.

Once you have taken all the necessary precautions for preparation and have confirmed which tools you will need for removal, you can proceed to locate the affected cylinder to begin removing the spark plug.

Locate the Affected Cylinder

Locating the affected cylinder and determining which spark plug is seized or needs replacing is the first step in removing a seized spark plug. If you’re having trouble pinpointing which cylinder is causing the problem, there are a few methods to help find it.

One way to perform this task is to look at the diagnostic codes stored on your vehicle’s computer if you have access to them. These codes will typically list out what is causing the problem. Look up the code and cross-reference it with your particular vehicle’s maintenance manual to help identify which spark plug needs to be replaced.

Another method to identify the seized spark plug involves checking for an uneven engine sound. When one of the cylinders does not fire properly, it will cause a noticeable change in the sound of your engine as it runs. Once you’ve identified which cylinder is making an odd sound, check that cylinder’s spark plugs for signs of dirt or damage. If they appear worn, they should be replaced.

No matter which method you use to determine which spark plug needs to be removed, it’s important to be thorough when conducting a visual inspection – especially if the spark plugs have been exposed to extreme weather conditions or if they haven’t been changed regularly. Once you have determined which cylinder needs attention and inspected its spark plugs, it’s time to move on to disconnecting the fuel and air supply of that cylinder before attempting to remove the seized spark plug.

Therefore, in order for us to successfully remove a seized spark plug we must first locate the affected cylinder by utilizing diagnostic codes and listening for an uneven engine sound. Armed with this knowledge we can now begin step two of our process and begin to disconnect the fuel or air supply in order for us move forward with removing the seized spark plug.

  • According to research, using a penetrating oil like WD-40 and allowing it to sit for at least 20-30 minutes can help loosen up a seized spark plug.
  • Once the oil has had time to penetrate, try using a locking pliers or wrench to loosen the plugged from the cylinder head.
  • A 2019 study found that in 75% of cases, these methods successfully removed a seized spark plug.


To remove a seized spark plug, one must first familiarize themselves with the affected cylinder by either accessing the diagnostic codes stored on the vehicle’s computer or listening for an uneven engine sound. Once the cylinder has been identified, it is important to be thorough when conducting a visual inspection of the spark plugs before disconnecting the fuel and air supply of the cylinder to proceed with removing the seized spark plug.

Disconnect the Fuel or Air Supply

Disconnecting the fuel or air supply is an important step before beginning the spark plug removal process. This prevents combustible materials from spilling out and potentially causing a fire risk. Depending on the engine type, you will either need to unplug the fuel line, or disconnect the air-intake tube. It’s a good idea to consult the user manual for your engine model’s specific instructions before attempting this step.

For instance, if your engine runs on gasoline, it will likely have two hoses connected to the fuel tank: one carrying fuel and one that returns unused fuel into the tank after running through the carburetor. Unhooking both hoses is necessary to eliminate any risk of sparks triggering an explosion of vaporous fuel. On the other hand, some engines are designed to run entirely on compressed air and require that you remove the air intake hose and filter before starting work on removing the old spark plug.

If you’re unsure what engine setup you have or which lines should be disconnected, it may be best to consult with a licensed mechanic beforehand. Some situations require professional assistance to prevent injury or further damage while attempting this task.

With any luck, after disconnecting whatever supply is necessary for your model engine, you can feel confident that no combustible substances can escape while working on removing the spark plug. Now that we have thoroughly ensured safety measures are taken, we can move on to gathering the necessary tools and materials needed to complete this task.

Tools and Materials Needed

Before attempting to remove a seized spark plug, it is important to have the proper tools and materials to perform the job properly. Depending on the situation, different tools and materials may be required. Some common items needed for this task include a wrench, impact driver, lubricant, and various socket sets or extensions.

The use of a wrench is necessary for unscrewing a spark plug that is stuck in place. Depending on the exact model of the car being worked on, a standard-size wrench may suffice, but newer models often require a deep-well socket and extension bar to access the fastener. An impact driver will also help loosen stubborn plugs if they are too tight to be removed with a wrench alone. Additionally, using some lubricant around the base of the spark plug can help reduce friction and make removal easier. Lastly, having various socket sets and extensions available may prove beneficial due to the various sizes used by different vehicles.

Leading into the next section about “Wrench, Impact Driver, Lubricant, etc.”, it is vital to have these common tools and materials on hand before attempting to remove a seized spark plug.

Wrench, Impact Driver, Lubricant, etc.

To remove a seized spark plug, you will need the right tools for the job. This includes a wrench, an impact driver, and oftentimes a lubricant. A wrench is essential for this task as it will loosen the spark plug from its spot. An impact driver offers additional help in removing difficult plugs due to its ability to ‘shock’ the plug loose. Lastly, a lubricant can be applied, which not only makes for easy removal but also protects metal components from corrosion or rusting due to the elements.

It should be noted that with any tool usage, there are certain safety precautions one must take when performing these tasks that may call into question the choice of either a wrench or impact driver to remove the seized spark plug. On the one hand, choosing a wrench offers more accuracy and control over how much force is used on the plug while preventing potential damage to the surrounding area. However, an impact driver can efficiently grab onto and release rusty metallic parts that are otherwise difficult to move with a standard wrench.

Overall, both tools have their advantages when it comes to removing seized spark plugs, so there is no ideal tool for this type of task; rather it comes down to personal preference based on individual skill level and the desired outcome. With the right set of tools needed for such tasks now addressed, it’s time to move on to the next step: removing the plug itself.

Removing the Plug

The first step to removing a seized spark plug is ensuring you have the right tools. A spark plug requires a 3/8 inch socket or wrench, as well as an extension, to fit over the plug and reach it in some engine compartments. You will also need penetrating oil, a torch, a lubricant spray like WD-40, a wire brush, and a ratchet for any necessary adjustments.

When removing the plug, start by spraying a generous amount of penetrating oil on the outside. Let it sit for a few hours before starting to loosen the plug. This will help lubricate the area and loosen up any rust or corrosion that may be preventing it from moving.

Next, use your ratchet fitted with the correct sockets to loosen it carefully. Move slowly so you don’t damage anything, including yourself, if anything slips off your ratchet handle and injury ensues! If you’re struggling after applying force with your ratchet, you may consider using a torch to heat the area surrounding the plug. When heated and lubricated with oil, this should release most plugs from their areas very easily. After loosening and releasing the plug, please inspect for any debris or corrosion buildup within its housing before continuing your maintenance routine.

Once the seized spark plug has been removed from its housing, clean out any debris or corrosion with a wire brush before determining what caused the seizure in the first place. While there is debate as to whether using a torch and penetrating oil is good practice when dealing with seized spark plugs, those who disagree argue that excessive heat applied to these parts runs the risk of damaging interior components that are essential for the efficient functioning of an engine system – making diagnosis and upkeep difficult down the line.

However, proponents of this method contend that when done correctly and with all safety precautions followed, these materials can be safely used to remove a seized spark plug without causing any major damage or risk of harm.

With this in mind, it is important to approach this issue thoughtfully and responsibly if opting for a torch or lubricant spray when removing a seized spark plug from its housing. This is key for safe diagnosis and maintenance tips that are discussed in detail throughout the upcoming section.

With all safety practices observed and prior knowledge gathered regarding proper removal techniques, we move on now to discussing diagnosis and maintenance tips for ensuring long-lasting performance from your vehicle’s engine system.

Diagnosis and Maintenance Tips

When a spark plug is seized, it can be difficult to diagnose the issue. This is because multiple possible factors could be causing the engine to fail.

One of the main reasons for seized spark plugs is a lack of regular maintenance. Spark plugs should be checked regularly to ensure they are clean and have no corrosion or rust. If these problems are left unchecked, the spark plug can become stuck in place and eventually seize. Regularly changing the spark plugs can help prevent this from happening.

Another possible reason for seized spark plugs is an engine running too hot. Heat is one of the main causes of seizing, as heat from the combustion process can cause the plug to bind up and get stuck in place. If an engine runs too hot, it is important to identify the cause and make necessary repairs before continuing, as this will help avoid further issues with seizing spark plugs.

Finally, rough driving habits can also contribute to seizure, as too many sudden stops and starts can increase strain on the spark plug and lead to seizing. Drivers should focus on maintaining consistent driving speeds and avoiding hard stops as much as possible.

Whether it’s due to a lack of regular maintenance or something else, recognizing symptoms and making necessary repairs quickly is essential when dealing with seized spark plugs. Taking proper care of your vehicle by conducting regular maintenance checks and following proper driving techniques is key to ensuring all components remain working properly.


In conclusion, removing a seized spark plug is an important task that cannot be overlooked. It can take some time and effort to complete, but with the right tools and knowledge, it is a relatively straightforward process. Prevention is the best approach when dealing with sparking plugs; regularly checking and replacing them as required can help reduce the risk of seizing.

When faced with a seized plug, use the right tools for the job. An impact wrench will make removal significantly more accessible, while lubricants such as WD-40 can also help break down any rust or build-up in the area. Reducing friction with pliers and gently jiggling or tapping the plug may also assist in its release. Lastly, inspect and clean any damage using a wire brush before reinserting your new spark plug.

Removing a seized spark plug isn’t always an easy task, but following these five simple steps should make it a much smoother and more straightforward process. Taking preventative measures such as regular maintenance checks can help avoid this situation altogether, but when faced with it – proper safety precautions and appropriate techniques are key for success.

Common Questions and Answers

What tools do I need to remove a seized spark plug?

The essential tool you need to remove a seized spark plug is an adjustable wrench. This will allow you to firmly grip and turn the spark plug as needed so that it loosens up enough for removal. You may also need an assortment of other tools depending on your engine types, such as a 6-point socket, an extension bar, a ratchet wrench, and a breaking bar.

What causes a spark plug to become seized?

The most common cause of a seized spark plug is corrosion. Corrosion, rust, and other residues can accumulate in the spark plug threads, making it difficult to unscrew. This is more likely to occur when the vehicle is left sitting for long periods without being used or when the engine has not been properly maintained. Other causes include using the wrong thread-locking compound, improper installation, and over-tightening.

What steps do I need to take to remove a seized spark plug safely?

1. Make sure the engine is cool. Seized spark plugs can be difficult to remove, so you must ensure that the engine isn’t too hot before attempting to remove it. Otherwise, you risk burning yourself or damaging the engine further.

2. Spray some penetrating oil around the base of the spark plug. Use a lightweight oil such as WD-40 and spray it in generous amounts around the base of the spark plug. The oil will help lubricate and loosen the seized plug so that you can more easily remove it without damaging it or the engine.

3. Gently tap around the base of the spark plug with a hammer and punch. This should help loosen and break up any accumulated rust on the seized sparking plug. Keep tapping until you feel it move slightly before attempting to unscrew it with a socket wrench or pliers.

4. Check if any pieces of metal have become stuck in the spark plug hole when removing it. If there are any metal pieces present, use some tweezers or needle nose pliers to remove them from within the spark plug hole before attempting to insert a new spark plug into it.

5. Install a new spark plug once all pieces have been removed from its housing and tightened securely with a socket wrench or socket pliers according to your engine’s specifications for torque requirements for spark plugs