2001 Subaru Impreza Spark Plug Replacement Guide

Spark plugs are one of the most critical components inside your engine that need to be maintained. There’s a likely chance you will need to replace your set of spark plugs several times during your ownership of a 2001 Subaru Impreza. Spark plugs are one of the most important parts inside your engine as they start the entire combustion process that starts and keeps your engine running for many thousands of miles. Like most engine parts and components, spark plugs experience wear over time and eventually need replacement, but fortunately this is a repair you can do on your own. Odds are, if you’ve found yourself here, you have no idea how to do that, or maybe you’d just like to know what kind of spark plugs you need to buy. The entire process of changing your spark plugs should take roughly 20-45 minutes. This article will go over everything you should need to know about your Subaru Impreza’s spark plugs, whether you need some baseline information or a full, step-by-step guide to performing a spark plug change.

Correct spark plugs on a 2001 Subaru Impreza

AUTOLITE 3923[/caption]For any 2001 Subaru Impreza, you can use AUTOLITE 3923 spark plugs. These will be an exact fit and will match the required specifications of your engine. As this 2001 Subaru Impreza features a 4 cylinder engine, ensure you purchase 4 spark plugs. We always try to recommend the best possible spark plugs for the money, and these spark plugs are either a factory recomendation or an equivalent replacement available in today’s market at an affordable price.

How often should I change my spark plugs?

Generally, it is advised that you replace spark plugs once every 20,000 to 40,000 miles. Of course, please make sure to check your owner’s manual to determine the exact interval determined by Subaru for the 2001 Impreza. Of course, if you drive your vehicle more aggressively or own a Impreza with some modifications, you may want to consider changing your spark plugs closer to the 20,000 miles end of that spectrum.

However, there are also classic signs of a car that needs a spark plug replacement earlier than the recommended schedule, such as:

  • Problems starting your engine
  • Rough idle
  • Engine misfiring

Consider that this list is absolutely not comprehensive, and these problems on their own do not necessarily point to the spark plugs being the solitary culprit. However, the best way to prevent any issues with your vehicle is to take care of it with regular maintenance, and you are definitely doing so with the responsible decision to replace your Subaru Impreza’s spark plugs on a regular basis.

Changing spark plugs on a 2001 Subaru Impreza

This is a process you can do on your own with some ordinary garage tools. Of course, consult your owner’s manual, as well as a factory service manual (FSM for short) or an equivalent Haynes or Chiltons manual. The video shown below does a good job of outlining the process.

Helpful Tools

We recommend having a spark plug gap tool in your arsenal. It’s an inexpensive tool that will come in handy frequently.
As noted before, you should be able to complete a spark plug change with some regular tools you most likely already have. However, there are a few tools that are specific to this job that you may not have, and we also want to recommend some commonplace tools that you should definitely have in your toolbox if you do not already.

  • A spark plug tester – this is definitely a niche tool, but it can save you lots of time. Although we’ve discussed spark plug replacement being a good thing to replace regularly and not just when issues occur, you may also be replacing your spark plugs because of a problem. This tool can help you diagnose the definite problem.
  • A set of spark plug sockets – These come in extremely handy because many standard sockets are not deep enough for spark plugs. Additionally, some spark plug holes are a bit smaller, so it requires a thinner wall like the one featured in the product here to fit. The linked product also features a magnet to keep a good hold of the spark plug so you do not drop it into your engine bay!
  • A torque wrench is a essential tool to have in your toolbox. You should check your FSM (factory service manual) to determine the correct torque rating to use when putting in the new spark plugs for your 2001 Subaru Impreza to be sure they are installed properly.
  • A spark plug gap tool. This allows you to check the gap of your spark plugs and increase or decrease it if necessary. Most plugs will come pregapped, but if this is not the case, you should for sure have one of these.

Tips for changing spark plugs on your 2001 Subaru Impreza

It is a great idea to have some dielectric grease handy.
Be sure to reference the video above before you attempt to repair the spark plugs on your 2001 Subaru Impreza, as well as review your factory service manual. Be sure to check the tips shown here to help you as you do this repair.

  • Your engine should be completely cold before you replace your spark plugs. Wait at least 30 minutes after any kind of operation before attempting to replace the spark plugs on your 2001 Subaru Impreza
  • Before starting, disconnect the negative terminal of your battery. You should always disconnect the battery anytime you work on the electrical system of your Subaru Impreza or any other vehicle.
  • Note that this is not official advice as many spark plug manufacturers advise against the use of anti-seize. However, I have heard from numerous old-school mechanics that they always apply a small amount of anti-seize to the threads of their spark plugs, especially on older vehicles.
  • It’s not a bad idea to use dielectric grease when installing new spark plugs. You can apply a small amount to the inside of the boot and the ceramic part of your spark plugs. It prevents voltage leak and helps avoid the misfortune of the boot fusing to the spark plug over time.
  • One of the most important things to remember is to avoid overtightening the plugs or worse, cracking them due to overtightenting. Use a torque wrench capable of lower, more precise torque ratings to be sure that you don’t make this mistake.

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