2008 GMC Yukon Spark Plug Replacement Guide

It is imperative that you ensure your spark plugs are in good condition. There’s a likely chance you will be required to replace your old and worn out spark plugs several times over the course of owning a 2008 GMC Yukon. Spark plugs are one of the most vital parts inside your engine as they begin the entire combustion process that starts and keeps your engine running for many thousands of miles. Like 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. Chances are, if you’ve found yourself here, you have no idea how to do that, or potentially 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 GMC Yukon’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 2008 GMC Yukon

CHAMPION 9405[/caption]For any 2008 GMC Yukon, you can use CHAMPION 9405 spark plugs. These will be an exact fit and will match the required specifications of your engine. As this 2008 GMC Yukon features an 8 cylinder engine, ensure you purchase 8 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 now 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 GMC for the 2008 Yukon. Of course, if you drive your vehicle more aggressively or own a Yukon 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 early, such as:

  • Engine misfiring
  • Rough idle
  • Problems starting your engine

As a quick note, keep in mind that this list is of course 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 routine maintenance, and you are definitely doing so with the responsible decision to replace your GMC Yukon’s spark plugs on a regular basis.

Changing spark plugs on a 2008 GMC Yukon

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

Helpful Tools

While not totally necessary, a spark plug tester is great to have.
As noted before, you should be able to do a spark plug change with some regular tools you probably 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 don’t already.

  • A torque wrench is a vital tool to have in your arsenal. You should check your FSM (factory service manual) to determine the correct torque rating to use when inserting the new spark plugs for your 2008 GMC Yukon to be confident 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 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. Also, 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 spark plug gap tool. This allows you to check the gap of your spark plugs and change it if necessary. Most plugs will come pregapped, but if this is not the case, you should absolutely have one of these.

Tips for changing spark plugs on your 2008 GMC Yukon

It is a great idea to have some dielectric grease handy.
Be sure to review the video above before you attempt to repair the spark plugs on your 2008 GMC Yukon, as well as review your FSM (factory service manual) or owner’s manual. Additionally, we have some tips below here to help you as you complete this repair.

  • 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.
  • 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 2008 GMC Yukon
  • Before starting, remove the negative terminal of your battery. You should always disconnect the battery anytime you work on the electrical system of your GMC Yukon or any other vehicle.
  • 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 tiny amount of anti-seize to the threads of their spark plugs, especially on older vehicles.
  • You might consider using dielectric grease when installing new spark plugs. You can apply a a little bit 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.

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