One of the most important aspects of vehicle maintenance is ensuring your spark plugs are in good working order. There’s a decent chance you will be required to replace your old and worn out spark plugs several times while you own a a 2005 Subaru Legacy. Spark plugs are one of the most critical components inside your engine as they trigger the entire combustion process that starts and keeps your engine running for many thousands of miles. Like 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. 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 approximately 20-45 minutes. This article will go over everything you’ll need to know about your Subaru Legacy’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 Subaru Legacy
Recommended 2.5L H4 2005 Subaru Legacy Spark Plugs
Recommended 2.5L H4 Turbocharged 2005 Subaru Legacy Spark Plugs
These spark plugs are an exact fit for their respective engines and will match the required specifications. As this 2005 Subaru Legacy 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 an affordable price.
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 exact interval determined by Subaru for the 2005 Legacy. Of course, if you drive your vehicle more aggressively or own a Legacy 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
- Rough idle
- Engine misfiring
Consider 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 organized maintenance, and you are definitely doing so with the responsible decision to replace your Subaru Legacy’s spark plugs on a regular basis.
Changing spark plugs on a 2005 Subaru Legacy
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 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 Subaru Legacy to be confident they are installed properly.
- 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 more straightforward to check the exact gap, and it comes in handy for countless 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 a problem. This tool can help you diagnose the definite 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!
Tips for changing spark plugs on your 2005 Subaru Legacy
- 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 small amount of anti-seize to the threads of their spark plugs, especially on older vehicles.
- 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.
- It’s not a bad idea to use 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.
- 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 Subaru Legacy or any other vehicle.
- 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 2005 Subaru Legacy