How to Change the Driver Side Spark Plugs in Your Subaru: A Step-by-Step Guide

If you own a Subaru car and you’re looking to save some money by doing your own engine maintenance, one task you can tackle is changing your driver side spark plugs. While it may seem daunting at first, it’s actually a relatively simple procedure that you can do with just a few tools and some patience.

In this article, we’ll provide you with a step-by-step guide on how to change the driver side spark plugs in your Subaru. We’ll also give you some tips and advice to help you do the job efficiently and safely. So, let’s get started!

Materials and Tools Needed

Before you start replacing your spark plugs, here are the materials and tools you’ll need:

  • A socket wrench with a spark plug socket
  • A spark plug gap gauge
  • Replacement spark plugs (make sure they are the right size and specification for your particular model of Subaru)
  • Dielectric grease
  • A torque wrench

Step 1: Preparing Your Subaru

To begin, you need to prepare your Subaru for the spark plug replacement. Start by opening the hood and locating the spark plug wires on the driver side of the engine. You may have to remove some parts (such as the air intake duct or engine cover) to access the spark plug wires.

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Once you have access to the spark plug wires, use a marker or some tape to label them according to which cylinder they connect to. This will ensure that you put them back in the right place when you’re done.

Step 2: Removing the Old Spark Plugs

Next, it’s time to remove the old spark plugs. Start by using your spark plug socket (attached to your socket wrench) to loosen and remove the first spark plug. Be gentle and make sure that you don’t damage the threads on the spark plug or in the spark plug well.

Once you have removed the old spark plug, use your spark plug gap gauge to measure the gap on the new spark plug. Make any necessary adjustments to ensure that the gap is correct before installing the new spark plug.

Before installing the new spark plug, apply a small amount of dielectric grease to the threads and ceramic insulator. This will help ensure that the spark plug installs easily and that it remains properly seated.

Finally, use your torque wrench to tighten the spark plug to the manufacturer’s specifications. Repeat this process for each of the remaining spark plugs.

Step 3: Replacing the Spark Plug Wires

Once you have replaced all of the spark plugs, it’s time to replace the spark plug wires. Remember to match the labels you made earlier to ensure that each wire connects to the correct cylinder.

Be careful when reinstalling the spark plug wires. They should fit snugly onto the spark plugs, but don’t force them too hard or you may damage the connectors.

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Step 4: Testing Your Subaru

Now that you have replaced all of the spark plugs and wires, it’s time to test your Subaru to make sure everything is working properly. Start your engine and check for any signs of misfires or other problems. If everything seems to be running smoothly, you’re all done!

Safety Tips and Warnings

  • Never attempt to replace your spark plugs when your engine is hot. Wait until it has cooled down to avoid burning yourself.
  • Always wear safety goggles to protect your eyes from debris and other hazards.
  • Make sure that your Subaru is on a level surface and that the parking brake is engaged before you start working on the engine.
  • Be sure to follow the manufacturer’s torque specifications when tightening your spark plugs.

Common Mistakes to Avoid

  • Using improper tools or sockets that don’t fit your spark plugs can lead to damaged threads and other problems.
  • Over-tightening your spark plugs can strip the threads or cause other damage.
  • Not reconnecting the spark plug wires in the correct order can lead to misfires and other engine problems.


How often should I change my spark plugs?

The lifespan of spark plugs varies depending on the type of plug and the conditions under which you drive your Subaru. As a general rule, you should plan to replace your spark plugs every 30,000 miles or so. Consult your owner’s manual or a trusted mechanic for specific recommendations.

Do I need any special tools to replace my spark plugs?

You’ll need a socket wrench with a spark plug socket, a spark plug gap gauge, a torque wrench, and some dielectric grease. These tools are readily available at most auto parts stores.

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Can I change all of my spark plugs at once?

Yes, you can change all of your spark plugs at once if you wish. It may take a bit longer, but it’s a good idea to replace all of your spark plugs at once in order to ensure consistent performance.

With these steps and tips, you can now change the driver side spark plugs in your Subaru with confidence. Remember to take your time and stay safe throughout the process, and your engine will thank you for it!

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Davis Bellew

As a Subaru owner and enthusiast, Davis has a deep understanding of the needs and concerns of Subaru drivers. He specializes in writing informative and engaging content about Subaru maintenance and repair, and his articles are always well-researched and easy to understand. When he's not writing, he enjoys hiking and photography.

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