2012 GMC Terrain Spark Plug Replacement Guide

Maintaining your vehicle is an incredibly rewarding task and learning how to replace your spark plugs is a great place to start. There’s a likely probability you will be required to replace your worn out spark plugs several times over the course of owning a 2012 GMC Terrain. Spark plugs are one of the most important parts inside your engine as they trigger the entire combustion process that starts and keeps your engine running for many thousands of miles. Similar to most engine components, spark plugs experience wear over time and eventually need to be replaced, 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 perhaps you’d just like to know what kind of spark plugs you need to buy. The complete process of changing your spark plugs should take approximately 20-45 minutes. This article will go over everything you should need to know about your GMC Terrain’s spark plugs, whether you need some general information or a full, step-by-step guide to performing a spark plug change.

Correct spark plugs on a 2012 GMC Terrain

AUTOLITE APP5263[/caption]For any 2012 GMC Terrain, you can use AUTOLITE APP5263 spark plugs. These will be an exact fit and will match the required specifications of your engine. Make sure you purchase the correct quantity of spark plugs for your engine corresponding to the number of cylinders. Sometimes manufacturers will bundle spark plugs in quantities that make it difficult to buy the exact amount you need for your engine. In this case, it is not a bad idea to purchase enough for your next two spark plug changes just so you will always have a new set ready to go. 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 a reasonable price.

How often should I change my spark plugs?

As a general recommendation, 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 GMC for the 2012 Terrain. Of course, if you drive your vehicle more aggressively or own a Terrain 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 telltale signs of a car that needs a spark plug replacement earlier than the recommended schedule, such as:

  • Rough idle
  • Problems starting your engine
  • Engine misfiring

As a quick note, keep in mind that this list is absolutely not comprehensive, and these problems on their own do not definitively point to the spark plugs being the standalone 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 GMC Terrain’s spark plugs on a regular basis.

Changing spark plugs on a 2012 GMC Terrain

This is a process you can do on your own with some standard 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

While not necessary, a spark plug tester is great to have.
As noted before, you should be able to accomplish a spark plug change with some regular tools you 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 for sure have in your toolbox if you don’t already.

  • A spark plug gap tool. This allows you to check the gap of your spark plugs and modify it if necessary. Most plugs will come pregapped, but if not, you should absolutely have one of these.
  • A set of spark plug sockets – These come in extremely handy because many standard sockets are not deep enough for spark plugs. In addition, 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 will want to check your FSM (factory service manual) to determine the correct torque rating to use when inserting the new spark plugs for your 2012 GMC Terrain to be certain they are installed properly.
  • 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 an issue. This tool can help you diagnose the exact problem.

Tips for changing spark plugs on your 2012 GMC Terrain

It is a great idea to have some dielectric grease handy.
Please make sure you reference the video above before you attempt to repair the spark plugs on your 2012 GMC Terrain, as well as review your factory service manual. Additionally, we have some tips below here to help you as you complete this repair.

  • Take this (unofficial advice) lightly 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 light coating of anti-seize to the threads of their spark plugs, especially on older vehicles.
  • You should replace spark plugs on a cold engine. You should wait at least 30 minutes after your engine has been running before attempting to replace the spark plugs on your 2012 GMC Terrain
  • Before starting, remove the negative terminal of your battery. It is wise to disconnect the battery anytime you work on the electrical system of your GMC Terrain or any other vehicle.
  • It isn’t a bad idea to use dielectric grease when installing new spark plugs. You can apply a a small dab to the inside of the boot and the ceramic part of your spark plugs. It lessens the chance of voltage leak and helps avoid the misfortune of the boot fusing to the spark plug over time.
  • The most important thing 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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