How To Remove A Seized Spark Plug?

Spark plugs mediate the relationship between your car’s ignition system and combustion chamber. These plugs send sparks of electricity towards the combustion chamber from the ignition system. Consequently, your engine comes on when the compressed fuel or air combines with the electricity created by these plugs. Hence, the spark plug is an essential component of any working engine.

Per the regular maintenance of vehicles, you need to replace the spark plugs for optimum performance. However, you may find that the spark plug is either seized or stuck. So, we have put together this step-by-step guide to help you remove a seized spark plug from your automobile.

How Do You Remove a Seized Spark Plug From an Aluminum Head?

How To Remove A Seized Spark Plug

The following steps will guide you in removing seized spark plugs from your vehicle:

Step 1: Determine the Positioning of Your Spark Plug

Some automobiles have their spark plugs located in hard places. Hence, you may find it challenging to reach those spark plugs. If you find yourself in such a situation, you may need a lift to gain better access to your spark plug.

Step 2: Pull the Spark Plug Cover Off the Spark Plug

All automobiles have a spark plug cover consisting of a wire and cap that holds the plug cap in place. Thus, when the plug generates a spark, the electricity gets conducted through this wire to the combustion chamber. You have to pull off this cap before you can remove the plug.

Step 3: Use Penetrating Oil and Spray It Down the Spark Plug Barrel

When you spray oil down the spark plug barrel, you create an excellent lubricating coat around the plug. The oil helps to loosen any rust or buildup causing the spark plug seizure.

Step 4: Wait a While

After lubricating, wait at least ten minutes to half an hour. The wait ensures the oil completely loosens the buildup that is causing the spark plug to seize. Note that the longer the delay, the better. If the plug proves challenging to remove, you may want to wait overnight before trying. After the wait, gently tap the end of the spark plug to help loosen it.

Step 5: Tighten the Spark Plug Slightly Before Trying to Loosen It

It would help turn the spark plug clockwise with your wrench to tighten it slightly. Next, turn the spark plug counterclockwise to loosen it. When you slightly tighten the spark plug, you help relieve the buildup around the threads. If you have carried out the necessary steps, but your spark plug is still stuck, you may need to immerse it in oil again.

Step 6: Turn on The Engine

When you turn on the engine, the heat helps to loosen the threads around the plug. Hence, the oil seeps deeply into the lines of the spark plug. To ensure you do not injure yourself, wait until the engine cools before further action. Once the engine has cooled, you can repeat steps one through four until you loosen your seized spark plug. After this, your seized spark plug should come off with ease. Additionally, you can repeat this procedure as many times as needed until you loosen your spark plug.

Related Reading: How long does it take to change spark plugs

Frequently Asked Questions on Seized Spark Plugs

We have collated these questions and answers to help clear the air on some common issues faced with seized spark plugs:

1. Can I Use WD-40 to Remove Spark Plugs?

Yes. While the WD-40 may not remove seized spark plugs by itself, it makes the work easier. Moreover, you can use the WD-40 to prevent corrosion by removing water from spark plugs.

2. Can You Spray Penetrating Oil on Spark Plugs?

Yes. Spraying penetrating oil down the barrel of your seized spark plug does help, and the oil helps in creating a good coating around the seized spark plug. Hence, the penetrating oil helps remove rust and buildup that can make the spark plug seize.

3. What Causes a Spark Plug to Seize?

Several reasons could cause your spark plug to seize, and one reason is corrosion. Although modern engines try to reduce the chances of having a corroded barrel or spark plug, these things still happen. Additionally, your spark plug could seize due to carbon buildup. Carbon buildup occurs when your engine is not running at optimal levels, especially in injection engines. Thus, the carbon builds up at the spark plugs tip, preventing easy removal.


Several reasons can cause your spark plugs to seize. As we have discussed, carbon buildup, corrosion, and other factors could be responsible for spark plug seizure. You could cover your plug caps adequately and ensure liquid does not seep through the barrel to prevent such incidents from happening. Furthermore, you can service your engine regularly to ensure it is running at optimal levels. If your plug has seized already, do not worry, you can address the issue yourself. Follow the step-by-step guide outlined above, and your seized spark plug will come off with ease.

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