Spark plugs are one of the most critical components inside your engine that need to be maintained. There’s a good probability you will need to replace your worn out spark plugs several times while you own a a 1999 Subaru Forester. 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. 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 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 approximately 20-45 minutes. This article will go over everything you’ll need to know about your Subaru Forester’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 1999 Subaru Forester
NGK 3764[/caption]For any 1999 Subaru Forester, you can use NGK 3764 spark plugs. These will be an exact fit and will match the required specifications of your engine. As this 1999 Subaru Forester 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?
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 Subaru for the 1999 Forester. Of course, if you drive your vehicle more aggressively or own a Forester 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 needs a spark plug replacement prematurely, such as:
- Engine misfiring
- Rough idle
- Problems starting your engine
Note that this list is absolutely not comprehensive, and these problems on their own do not definitively 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 Subaru Forester’s spark plugs on a regular basis.
Changing spark plugs on a 1999 Subaru Forester
This is a process you can 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 complete a spark plug change with some ordinary tools you probably 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 don’t already.
- A torque wrench is a vital tool to have in your arsenal. You should check your FSM (factory service manual) to determine the correct torque rating to use when inserting the new spark plugs for your 1999 Subaru Forester to be confident they are installed properly.
- 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 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!
- 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 this is not the case, 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 useful for countless other jobs.
Tips for changing spark plugs on your 1999 Subaru Forester
Ensure you review the video above before you attempt to repair the spark plugs on your 1999 Subaru Forester, 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 perform this repair.
- During this process, one of the most vital things to ensure you do 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 completely COLD before you replace your spark plugs. You should wait at least 30 minutes after any kind of operation before attempting to replace the spark plugs on your 1999 Subaru Forester
- 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 light coating of anti-seize to the threads of their spark plugs, especially on older vehicles.
- 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 Subaru Forester or any other vehicle.
- 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.