Maintaining your vehicle is an incredibly rewarding task and learning how to replace your spark plugs is a great place to start. There’s a good chance you will be required to replace your old spark plugs several times while you own a a 2009 Mazda MX-5 Miata. Spark plugs are one of the most vital components inside your engine as they trigger the entire combustion process that starts and keeps your engine running for many thousands of miles. Similar to most engine parts and components, 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 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 roughly 20-45 minutes. This article will go over everything you will need to know about your Mazda MX-5 Miata’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 2009 Mazda MX-5 Miata
For any 2009 Mazda MX-5 Miata, you can use DENSO 5339 spark plugs. These will be an exact fit and will match the required specifications of your engine. As this 2009 Mazda MX-5 Miata features a 4 cylinder engine, ensure you purchase 4 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 a reasonable 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 specific interval determined by Mazda for the 2009 MX-5 Miata. Of course, if you drive your vehicle more aggressively or own a MX-5 Miata 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 potentially need a spark plug replacement earlier than the recommended schedule, such as:
- Problems starting your engine
- Rough idle
- Engine misfiring
Note that this list is certainly not comprehensive, and these problems on their own do not necessarily 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 Mazda MX-5 Miata’s spark plugs on a regular basis.
Changing spark plugs on a 2009 Mazda MX-5 Miata
This is a process you can do on your own with some commonplace 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.
As noted before, you should be able to complete a spark plug change with some regular tools you most 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 commonplace tools that you should for sure have in your toolbox if you do not already.
- 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 exact problem.
- A set of spark plug sockets – These come in extremely 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 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 definitely 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 helpful for a decent number of other jobs.
- A torque wrench is a vital tool to have in your arsenal. You will want to check your FSM (factory service manual) to determine the correct torque rating to use when installing the new spark plugs for your 2009 Mazda MX-5 Miata to be certain they are installed properly.
Tips for changing spark plugs on your 2009 Mazda MX-5 Miata
Be sure to watch the video above before you attempt to repair the spark plugs on your 2009 Mazda MX-5 Miata, as well as review your factory service manual. Additionally, we have some tips below here to help you as you complete this repair.
- Before beginning, 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 Mazda MX-5 Miata or any other vehicle.
- 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 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.
- 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.
- Your engine should be completely 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 2009 Mazda MX-5 Miata