Spark Plug FAQs
Spark plugs are essential to your Subaru’s performance. If they fail, your engine can misfire, lose power, or suffer from poor fuel economy. Whether you're looking to replace your spark plugs or just want to learn more, this guide answers the most common questions Subaru owners have.
How Do I Know Which Spark Plugs My Subaru Needs?
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The right spark plug type depends on your Subaru’s model, year, and engine type. To find the right ones, you'll need to match the following:
- Plug type (Iridium, Platinum, or Copper)
- Thread size and length
- Gap specification (measured in millimeters)
For an exact match, check your owner’s manual or visit our Subaru Spark Plug Guide.
How Difficult Is It to Change My Own Spark Plugs?
Replacing spark plugs on a Subaru can be moderately difficult, depending on the engine layout. Some models, like the WRX or Outback, have tight engine bays, making access tricky. However, with the right tools and a step-by-step Spark Plug Replacement Tutorial, DIY replacement is possible.
What Tools Do I Need to Change My Spark Plugs?
To replace your spark plugs, you'll need:
- Ratchet and extension (long extensions for deep spark plug wells)
- Spark plug socket (with a rubber insert to grip the plug)
- Torque wrench (to ensure proper tightening)
- Gapping tool (to adjust the spark plug gap if necessary)
- Dielectric grease and anti-seize compound (optional but recommended)
How Often Should I Change My Subaru’s Spark Plugs?
The recommended replacement interval depends on the spark plug type:
- Iridium and Platinum: Every 60,000 to 100,000 miles
- Copper: Every 20,000 to 30,000 miles
Check your owner’s manual for your specific model's recommendation. If you're experiencing rough idling or misfires, read Diagnosing a Failing Spark Plug to see if it’s time for a replacement.
Can I Damage My Engine by Installing Spark Plugs Incorrectly?
Yes! Incorrect installation can lead to:
- Engine misfires (if the plug isn’t seated correctly)
- Poor fuel economy (if the gap is off)
- Thread damage (if over-tightened)
To avoid these issues, follow proper torque specs and installation techniques. Our Spark Plug Replacement Guide walks you through it step by step.
Do I Need to Remove Engine Components to Access the Spark Plugs?
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For some Subaru models, yes. Boxer engines have spark plugs positioned on the sides of the engine, making access tight. You may need to remove:
- The intake manifold (for some turbocharged models)
- The battery or air box (for better access)
A repair manual or video tutorial specific to your model can help.
Should I Use OEM Spark Plugs or Aftermarket Ones?
We always recommend OEM Subaru spark plugs because they are designed for optimal performance, longevity, and fitment. Aftermarket options may:
- Have incorrect heat ranges
- Wear out faster
- Cause misfires or check engine lights
For a detailed comparison, check out OEM vs. Aftermarket Spark Plugs.
How Much Do Subaru Spark Plugs Cost?
Prices vary depending on the plug type and Subaru model but typically fall in the following ranges:
- OEM Iridium spark plugs: Up to $30 each
- Platinum spark plugs: Up to $20 each
- Copper spark plugs: Up to $20 each
Find the right spark plugs for your Subaru here: Shop Subaru Spark Plugs.
Where Should I Buy Subaru Spark Plugs?
For genuine OEM spark plugs at competitive prices, Subaru Parts Plus is the best place to shop. We offer:
- 100% OEM parts – No knock-offs, just factory-approved plugs
- Fast shipping – Get your parts quickly
- Expert support – Our team knows Subaru parts inside and out
Keeping your Subaru’s spark plugs in top shape ensures smooth performance, better fuel efficiency, and a longer engine life. If you’re due for a replacement, stick with OEM spark plugs for the best results. Browse our full selection of OEM Subaru Spark Plugs today!