Spark plugs are one of the most critical components inside your engine that need to be maintained. There’s a good chance you will need to replace your old spark plugs several times while you own a a 2005 Ford Focus. Spark plugs are one of the most important 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 to be swapped out for new replacements, 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 entire process of changing your spark plugs should take about 20-45 minutes. This article will go over everything you will need to know about your Ford Focus’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 2005 Ford Focus
For any 2005 Ford Focus, you can use DENSO 4713 spark plugs. These will be an exact fit and will match the required specifications of your engine. As this 2005 Ford Focus 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 now at a reasonable price.
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 exact interval determined by Ford for the 2005 Focus. Of course, if you drive your vehicle more aggressively or own a Focus 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 early, such as:
- Problems starting your engine
- Rough idle
- Engine misfiring
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 Ford Focus’s spark plugs on a regular basis.
Changing spark plugs on a 2005 Ford Focus
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 (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 do a spark plug change with some ordinary 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 torque wrench is a essential tool to have in your garage. You will want to check your FSM (factory service manual) to determine the correct torque rating to use when putting in the new spark plugs for your 2005 Ford Focus to be confident they are installed properly.
- 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 more straightforward to check the exact gap, and it comes in handy for a decent number of other jobs.
- 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 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. In addition, 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!
Tips for changing spark plugs on your 2005 Ford Focus
Ensure you review the video above before you attempt to repair the spark plugs on your 2005 Ford Focus, as well as review your FSM (factory service manual). Also, see the tips included below here to help you as you perform this repair.
- It isn’t a bad idea to use dielectric grease when installing new spark plugs. You can apply a a small dab 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.
- 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.
- Before starting, disconnect the negative terminal of your battery. You should always disconnect the battery anytime you work on the electrical system of your Ford Focus or any other vehicle.
- 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.
- Your engine should be cold before you replace your spark plugs. You should wait at least 30 minutes after your engine has been running before attempting to replace the spark plugs on your 2005 Ford Focus