DIY Guide: How to Change Spark Plugs on Your 2002 Subaru Impreza Like a Pro

If you are a car enthusiast or a Subaru owner, you might want to learn how to do some basic maintenance tasks yourself. Changing spark plugs is one of these tasks, and it can save you some money if you do it yourself. In this article, we will guide you through the process of changing spark plugs on a 2002 Subaru Impreza.

Tools and Materials Required

Before you start, make sure you have all the necessary tools and materials. Here’s what you’ll need:

  • Spark plugs
  • Socket wrench with extension
  • Spark plug socket
  • Torque wrench
  • Anti-seize compound
  • Dielectric grease

Step-by-Step Guide

1. Remove the Old Spark Plugs

Start by opening the hood of your car and locating the engine. Each spark plug has a wire attached to it, so you need to remove these wires first. Grip the wire by the boot (the rubber cover), and twist and pull it gently. Do not pull on the wire itself, or you may damage it.

Once you’ve removed the wires, use the socket wrench and spark plug socket to remove the old spark plugs. Turn the socket wrench counterclockwise to loosen the spark plug, then twist it out by hand. Repeat this for all four spark plugs.

2. Install the New Spark Plugs

Take the new spark plugs out of their packaging and check the gap between the electrodes. The gap should match the specifications outlined in your car’s manual. If it doesn’t, adjust the gap using a spark plug gap tool.

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Dab a small amount of anti-seize compound on the spark plug threads to prevent them from seizing or getting stuck in the engine block. Then, insert the new spark plug into the socket wrench and carefully place it in the spark plug hole, turning it clockwise by hand. Tighten the spark plug with the torque wrench until you feel resistance.

3. Reattach the Wires

Reattach the wires to the new spark plugs, making sure they are snugly seated. Don’t forget to apply a thin layer of dielectric grease to the inside of each boot to prevent moisture from getting in and preventing proper conductivity.

Repeat this process for each spark plug until you have replaced all four.

4. Test Your Work

Once you’ve replaced all the spark plugs, start your engine and listen carefully. Does it sound smooth and steady? If there is any hesitation or roughness, recheck your work and make sure each spark plug is properly tightened. In addition, be sure to double-check that all wiring connections are secure.


Here are some common issues that can arise during the process of changing spark plugs, and what to do about them:

  • Broken Spark Plugs: If a spark plug breaks during the removal process, it can be tricky to remove the broken piece. You might have to use a special tool designed for this purpose, or you may need to take the car to a professional.
  • Cracked Spark Plugs: If you notice any cracks in the ceramic insulator or the electrode tip of the old spark plugs, this might indicate a deeper problem with your engine that needs to be assessed as soon as possible.
  • Mismatched Spark Plugs: Using spark plugs that are not compatible with your car can cause a number of problems such as misfires, rough idling, and increased emissions. Always consult your car’s manual for the correct spark plug type and gap specifications.
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Tips and Tricks

Here are some tips and tricks that can make changing spark plugs easier and safer:

  • Use an Extension: Spark plugs can be difficult to reach in some cars. An extension for your socket wrench can help give you more reach and make it easier to fit the spark plug socket onto the spark plugs.
  • Take Your Time: Make sure you don’t rush through the process of changing spark plugs. It’s essential to be patient when working with engines so that you don’t miss anything or do something improperly.
  • Wear Gloves: Grease and oil can easily get on your hands while changing spark plugs. Wearing gloves can protect your skin and also keep your hands clean.


Learning how to change spark plugs is a helpful skill for any car enthusiast or Subaru owner. By following this guide, you can save money and do basic maintenance at home. Remember to take your time, ensure you have all the necessary tools and materials, and follow the steps carefully. With this DIY guide, you now can change the spark plugs on your 2002 Subaru Impreza like a professional.

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Billy Covington

With a passion for all things automotive, Billy is our go-to expert on Subaru performance upgrades and modifications. He's been featured in several car magazines and blogs, and his extensive knowledge and expertise make him a valuable member of our team. When he's not working on cars, he enjoys playing guitar and writing music.

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