Most Subaru Outbacks use iridium- or platinum-tipped spark plugs with long life, rather than copper. The exact type depends on the model year and the engine code (such as FA, FB, EJ, EZ, or EZ36).
Overview of spark plug types in Subaru Outbacks
The following categories cover the plug types you’re most likely to encounter across the Outback lineup.
- Iridium-tipped spark plugs: Common in newer engines and vehicle generations; they offer long life and reliable ignition with a small center electrode for efficient firing.
- Platinum-tipped spark plugs: Used in some older Subaru engines or as a mid-range option; longer life than copper but generally shorter than iridium.
- Copper-core spark plugs: Found on older or very early Subarus; provide good conductivity but shorter service life and are uncommon in current Outbacks.
In practice, most current Outbacks (2010s and later) use iridium- or platinum-tipped plugs. To be certain, verify the engine code and consult the OEM parts catalog or your owner's manual.
How to determine the exact spark plug for your Outback
To confirm the exact plug specification for your car, follow these steps:
- Identify your engine code and model year (found in the VIN sticker or owner's manual).
- Look up the OEM spark plug spec for that engine code in Subaru's official service information or the dealer’s parts catalog.
- Cross-check with a reputable parts retailer by entering your engine code to obtain the exact OEM replacement part number and gap.
- If in doubt, contact a Subaru dealer or a trusted mechanic for the correct plug type and gap.
Note that plug brands (NGK or Denso) and the exact part number can vary by market and production run, but iridium or platinum plugs are the norm for modern Outbacks.
Common engine codes you may encounter
Outbacks use a variety of engine families by generation. Here are some you might see when determining spark plugs:
- FA-series (e.g., FA20, FA24) for newer 2.0L/2.4L engines.
- FB-series (e.g., FB25) for 2.5L engines in many 2010s models.
- EJ-series (e.g., EJ25) in older models prior to the 2010s.
- EZ-series (e.g., EZ36) for some 3.6L variants.
Knowing the correct engine code helps ensure you buy the right plug and gap. After identifying your code, verify the exact OEM part number with official Subaru documentation or a trusted parts retailer.
Replacement intervals and driving conditions
Plug life depends on the plug type and driving conditions. The following guidelines cover typical expectations, but you should always follow the official service interval for your vehicle:
- Most iridium- or platinum-tipped plugs in recent Outbacks are rated for about 60,000–100,000 miles under normal driving.
- Copper-core plugs—the least common in modern Outbacks—often require changes around 20,000–40,000 miles in typical use.
- Severe driving conditions (frequent short trips, frequent stop-and-go, heavy towing, dusty or hot environments) can shorten plug life and may require earlier inspection or replacement.
Always consult the owner's manual or dealer service bulletin for your exact model to set the appropriate replacement interval.
Summary
In short, a Subaru Outback generally uses iridium- or platinum-tipped spark plugs, with the precise type determined by engine code and year. Copper plugs are largely outdated for modern models. Verify the engine code and consult the OEM catalog to confirm the exact plug part and gap for your vehicle.