There’s a good chance you will be required to replace your old and worn out spark plugs several times during your ownership of a 2015 Toyota Highlander. Spark plugs are one of the most critical parts inside your engine as they start the entire combustion process that starts and keeps your engine running for many thousands of miles. Similar to most engine parts, spark plugs experience wear over time and eventually need replacement, 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 maybe 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 will need to know about your Toyota Highlander’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 2015 Toyota Highlander
For any 2015 Toyota Highlander, you can use AUTOLITE XP5325 spark plugs. These will be an exact fit and will match the required specifications of your engine. Make certain that you purchase the correct amount of spark plugs for your engine corresponding to the number of cylinders. Often, 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 a good 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 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 Toyota for the 2015 Highlander. Of course, if you drive your vehicle more aggressively or own a Toyota Highlander 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
- Engine misfiring
- Rough idle
As a quick note, keep in mind that this list is certainly not comprehensive, and these problems on their own do not necessarily 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 2015 Toyota Highlander’s spark plugs on a regular basis.
Changing spark plugs on a 2015 Toyota Highlander
This is a process you should be able to do on your own with some ordinary garage tools. Of course, consult your owner’s manual, as well as a factory service manual 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 complete 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 absolutely have in your toolbox if you do not already.
- A spark plug gap tool. This allows you to check the gap of your spark plugs and increase or decrease it if necessary. Most plugs will come pregapped, but if not, you should definitely 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 a decent number of other jobs.
- 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 torque wrench is a vital tool to have in your arsenal. You will want to check your FSM (factory service manual) or owner’s manual to determine the correct torque rating to use when installing the new spark plugs for your 2015 Toyota Highlander to be confident 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 an issue. This tool can help you diagnose the exact problem.
Tips for changing spark plugs on your 2015 Toyota Highlander
Please make sure you reference the video above before you attempt to repair the spark plugs on your 2015 Toyota Highlander, 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.
- 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 tiny 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.
- You should replace spark plugs on a cold engine. You should wait at least 30 minutes after any kind of operation before attempting to replace the spark plugs on your 2015 Toyota Highlander
- Before you begin, remove the negative terminal of your battery. You should always disconnect the battery anytime you work on the electrical system of your Toyota Highlander or any other vehicle.