How To Replace The Spark Plugs In A Subaru Forester?

In this article, you will learn how to replace the spark plugs in a Subaru Forester. We will guide you through the step-by-step process, explaining everything you need to know to complete this task successfully. By the end of this article, you will feel confident in your ability to replace the spark plugs in your Subaru Forester and keep your car running smoothly.

To begin, gather all the necessary tools and materials, including a ratchet, extension, spark plug socket, and new spark plugs. Park your Forester on a level surface and let the engine cool down. Open the hood and locate the spark plug wires, which are usually attached to the top of the engine. Gently twist and pull each wire to disconnect it from the spark plug. Use the ratchet, extension, and spark plug socket to remove the old spark plugs. Finally, install the new spark plugs and reconnect the spark plug wires, making sure they are securely attached.


Before you begin replacing the spark plugs in your Subaru Forester, make sure you have gathered all the necessary tools. You will need a spark plug socket, a ratchet, a torque wrench, protective gloves, and eyewear. Additionally, you should park your vehicle on a level surface to ensure stability during the process. Finally, it is essential to allow the engine to cool down before you start.

Locating the Spark Plugs

To locate the spark plugs, you need to open the hood of your Subaru Forester. Once the hood is open, take a look at the engine cylinder layout. This layout will help you identify the location of the spark plugs. You should also identify the spark plug wires, which are usually connected to the top of the spark plugs.

How To Replace The Spark Plugs In A Subaru Forester?

Removing the Old Spark Plugs

To remove the old spark plugs, start by disconnecting the spark plug wires from the spark plugs. Be careful when doing this, as the wires can be delicate. Once the wires are disconnected, use a spark plug socket and a ratchet to loosen and remove the old spark plugs. As you remove each spark plug, take a moment to inspect it for signs of wear, such as erosion or fouling.

Preparing the New Spark Plugs

Before installing the new spark plugs, it is important to check the gap. The gap refers to the distance between the center and ground electrode of the spark plug. Use a gap tool or a feeler gauge to ensure that the gap matches the manufacturer’s specifications for your Subaru Forester. Additionally, apply a small amount of anti-seize compound to the threads of the new spark plugs to prevent them from seizing in the engine cylinder. Finally, hand-tighten the new spark plugs into the engine cylinder, making sure not to overtighten them.

How To Replace The Spark Plugs In A Subaru Forester?

Installing the New Spark Plugs

Once the new spark plugs are prepared, it’s time to install them. Start by tightening each spark plug using a torque wrench. Refer to your vehicle’s manual or the spark plug manufacturer’s specifications for the proper torque value. Tightening the spark plugs to the correct torque ensures a secure fit without damaging the engine cylinder. After tightening the spark plugs, reconnect the spark plug wires to the corresponding plugs. Make sure each wire is securely attached to avoid any misfires or poor connections. Finally, double-check all connections to ensure everything is properly installed.

Reassembling and Final Steps

After installing the new spark plugs, replace any engine covers that were removed during the process. It is crucial to reinstall these covers to protect the spark plugs and other engine components. Once the covers are back in place, start the vehicle and listen for any unusual sounds. If you hear any strange noises, promptly address the issue. Additionally, check for any engine warning lights on the dashboard. If any warning lights are illuminated, have your vehicle inspected to identify the cause.

How To Replace The Spark Plugs In A Subaru Forester?

Safety Tips

During the spark plug replacement process, it is crucial to prioritize your safety. Always wear protective gloves and eyewear to protect your hands and eyes. Additionally, make sure to disconnect the battery before working on the spark plugs. Disconnecting the battery reduces the risk of electrical shock or accidental starting of the engine. Finally, handle the spark plugs with care to avoid damage. They are delicate and can easily be broken if mishandled.

Common Mistakes to Avoid

When replacing spark plugs, there are a few common mistakes that should be avoided. One common mistake is overtightening or undertightening the spark plugs. Overtightening can damage the engine cylinder, while undertightening can lead to loose spark plugs and poor connections. Another mistake to avoid is mixing up the spark plug wires. Each wire should be connected to the corresponding spark plug to ensure proper firing sequence and engine performance. Lastly, do not skip the inspection of the old spark plugs. Examining the old spark plugs can provide valuable insight into the condition of your engine.

How To Replace The Spark Plugs In A Subaru Forester?

Benefits of Regular Spark Plug Replacement

Regular spark plug replacement offers several benefits for your Subaru Forester. One major advantage is improved fuel efficiency. New spark plugs provide a strong and consistent spark, ensuring efficient combustion of fuel in the engine cylinders. This improved combustion leads to better fuel mileage. Additionally, replacing the spark plugs enhances engine performance. With new spark plugs, your engine will have a smoother idle, improved acceleration, and reduced engine misfires. Finally, regularly replacing the spark plugs can help prevent engine misfires. Misfires can lead to decreased power, increased emissions, and potential engine damage.


Replacing the spark plugs in a Subaru Forester is a straightforward maintenance task that can significantly improve the vehicle’s performance and fuel efficiency. By following the proper steps and precautions outlined in this article, you can successfully replace the spark plugs and ensure the smooth operation of your Subaru Forester’s engine. Regular spark plug replacement is a simple yet effective way to keep your vehicle running at its best. So, don’t neglect this essential maintenance task and enjoy the benefits it brings to your Subaru Forester.

How To Replace The Spark Plugs In A Subaru Forester?

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