It is imperative that you ensure your spark plugs are in good condition. There’s a good chance you will need to replace your set of spark plugs several times while you own a a 1998 GMC T Series Truck. Spark plugs are one of the most critical components 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 parts, spark plugs experience wear over time and eventually need to be swapped out for new replacements, 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 complete process of changing your spark plugs should take roughly 20-45 minutes. This article will go over everything you’ll need to know about your GMC T Series Truck’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 1998 GMC T Series Truck
For any 1998 GMC T Series Truck, you can use BOSCH 6722 spark plugs. These will be an exact fit and will match the required specifications of your engine. As this 1998 GMC T Series Truck 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 a reasonable 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 exact interval determined by GMC for the 1998 T Series Truck. Of course, if you drive your vehicle more aggressively or own a T Series Truck 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 prematurely, such as:
- Problems starting your engine
- Rough idle
- Engine misfiring
Consider that this list is of course 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 organized maintenance, and you are definitely doing so with the responsible decision to replace your GMC T Series Truck’s spark plugs on a regular basis.
Changing spark plugs on a 1998 GMC T Series Truck
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.
As noted before, you should be able to do 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 general tools that you should definitely have in your toolbox if you don’t already.
- 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 very 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 for sure have one of these.
- I also highly recommend you have a feeler gauge as it makes it a bit more straightforward to check the exact gap, and it is useful for countless other jobs.
- A torque wrench is a very important 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 1998 GMC T Series Truck to be certain they are installed properly.
Tips for changing spark plugs on your 1998 GMC T Series Truck
Ensure you review the video above before you attempt to repair the spark plugs on your 1998 GMC T Series Truck, as well as review your factory service manual. Additionally, we have some tips below here to help you as you complete this repair.
- 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.
- You might consider using dielectric grease when installing new spark plugs. You can apply a a very light coating 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.
- 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.
- Before starting, remove 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 T Series Truck or any other vehicle.
- Your engine should be completely COLD before you replace your spark plugs. Wait at least 30 minutes after your engine has been running before attempting to replace the spark plugs on your 1998 GMC T Series Truck