Spark plugs are one of the most critical components inside your engine that need to be maintained. There’s a good chance you will be required to replace your set of spark plugs several times during your ownership of a 2015 GMC Sierra 3500. Spark plugs are one of the most critical components 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 parts, spark plugs experience wear over time and eventually need replacement, but fortunately this is a repair you can do yourself. Odds 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 complete 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 Sierra 3500’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 2015 GMC Sierra 3500
CHAMPION 9405[/caption]For any 2015 GMC Sierra 3500, you can use CHAMPION 9405 spark plugs. These will be an exact fit and will match the required specifications of your engine. As this 2015 GMC Sierra 3500 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 in today’s market at an affordable price.
How often should I change my spark plugs?
Very 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 specific interval determined by GMC for the 2015 Sierra 3500. Of course, if you drive your vehicle more aggressively or own a Sierra 3500 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 prematurely, such as:
- Rough idle
- Problems starting your engine
- Engine misfiring
Consider 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 routine maintenance, and you are definitely doing so with the responsible decision to replace your GMC Sierra 3500’s spark plugs on a regular basis.
Changing spark plugs on a 2015 GMC Sierra 3500
This is a process you should be able to do on your own with some commonplace 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.
As noted before, you should be able to do a spark plug change with some ordinary 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 general tools that you should absolutely have in your toolbox if you don’t already.
- A torque wrench is a vital tool to have in your toolbox. You will want to check your factory service manual to determine the correct torque rating to use when putting in the new spark plugs for your 2015 GMC Sierra 3500 to be certain they are installed properly.
- 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 something going wrong. This tool can help you diagnose the exact 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 modify it if necessary. Most plugs will come pregapped, but if not, you should absolutely 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 comes in handy for countless other jobs.
Tips for changing spark plugs on your 2015 GMC Sierra 3500
Please make sure you watch the video above before you attempt to repair the spark plugs on your 2015 GMC Sierra 3500, as well as review your FSM (factory service manual) or owner’s manual. Be sure to check the tips shown here to help you as you do 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.
- Before you begin, disconnect the negative terminal of your battery. It’s a good idea to disconnect the battery anytime you work on the electrical system of your GMC Sierra 3500 or any other vehicle.
- Your engine should be 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 2015 GMC Sierra 3500
- 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 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.