One of the most important aspects of vehicle maintenance is ensuring your spark plugs are in good working order. There’s a good chance you will need to replace your set of spark plugs several times while you own a a 2008 GMC Sierra 2500. Spark plugs are one of the most critical parts inside your engine as they trigger 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 replacement, but fortunately this is a repair you can do yourself. Chances 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 entire process of changing your spark plugs should take about 20-45 minutes. This article will go over everything you’ll need to know about your GMC Sierra 2500’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 Sierra 2500
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 specific interval determined by GMC for the 2008 Sierra 2500. Of course, if you drive your vehicle more aggressively or own a Sierra 2500 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 may need a spark plug replacement prematurely, such as:
- Problems starting your engine
- Rough idle
- Engine misfiring
Note that this list is absolutely not comprehensive, and these problems on their own do not definitively 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 GMC Sierra 2500’s spark plugs on a regular basis.
Changing spark plugs on a 2008 GMC Sierra 2500
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
- 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 this is not the case, you should for sure have one of these.
- I also highly recommend you have a feeler gauge as it makes it a bit easier to check the exact gap, and it is helpful for quite a few other jobs.
- A torque wrench is a essential tool to have in your arsenal. You will want to check your factory service manual to determine the correct torque rating to use when inserting the new spark plugs for your 2008 GMC Sierra 2500 to be sure they are installed properly.
- A set of spark plug sockets – These come in very 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 spark plug tester – this is definitely a niche tool, but it can save you a ton 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.
Tips for changing spark plugs on your 2008 GMC Sierra 2500
- Before starting, disconnect the negative terminal of your battery. It is wise to disconnect the battery anytime you work on the electrical system of your GMC Sierra 2500 or any other vehicle.
- During this process, one of the most vital things to ensure you do 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.
- 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.
- Your engine should be cold before you replace your spark plugs. Ensure you wait at least 30 minutes after any kind of operation before attempting to replace the spark plugs on your 2008 GMC Sierra 2500
- 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.