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 likely chance you will be required to replace your old spark plugs several times over the course of owning a 2008 Ford F-350 Super Duty. 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 components, 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 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 about 20-45 minutes. This article will go over everything you should need to know about your Ford F-350 Super Duty’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 2008 Ford F-350 Super Duty
How often should I change my spark plugs?
In general, 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 Ford for the 2008 F-350 Super Duty. Of course, if you drive your vehicle more aggressively or own a F-350 Super Duty 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 early, such as:
- Engine misfiring
- Rough idle
- Problems starting your engine
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 Ford F-350 Super Duty’s spark plugs on a regular basis.
Changing spark plugs on a 2008 Ford F-350 Super Duty
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) or an equivalent Haynes or Chiltons manual. The video shown below does a good job of outlining the process.
Helpful Tools
- 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 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 is helpful for countless other jobs.
- A torque wrench is a very important tool to have in your collection. You will want to check your factory service manual to determine the correct torque rating to use when inserting the new spark plugs for your 2008 Ford F-350 Super Duty to be sure they are installed properly.
- A set of spark plug sockets – These come in extremely 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!
- 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 definite problem.
Tips for changing spark plugs on your 2008 Ford F-350 Super Duty
- 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.
- Your engine should be 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 2008 Ford F-350 Super Duty
- Before starting, disconnect the negative terminal of your battery. It is wise to disconnect the battery anytime you work on the electrical system of your Ford F-350 Super Duty or any other vehicle.
- 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 lessens the chance of voltage leak and helps avoid the misfortune of the boot fusing to the spark plug over time.
- 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.