What type of spark plugs do subarus use?
Most modern Subarus use iridium or platinum spark plugs from NGK or Denso, with copper plugs mainly found on older EJ-series engines.
Overview of plug types in Subaru engines
Subaru’s engine lineup has evolved over time. Older EJ-series engines commonly used copper-core plugs that required more frequent replacement, while newer FA and FB family engines typically rely on iridium or platinum plugs designed for longer service life and consistent performance. The exact type, heat range, and gap are engine-specific, so owners should always consult the official documentation for their vehicle to ensure the correct specification.
Common brands and plug options
Subaru engines are routinely serviced with spark plugs from the two major aftermarket suppliers, NGK and Denso. Both brands offer iridium- and platinum-tipped options that meet Subaru’s heat-range and reach requirements. Copper-core plugs appear primarily on older or specialized configurations and are less common on current models.
- NGK Iridium or Platinum plugs for many modern Subaru engines
- Denso Iridium or Platinum plugs as a widely compatible alternative
- Copper-core plugs used on some older EJ-series engines, but still less common in contemporary models
Note: Do not mix brands or tip materials unless the manufacturer’s specifications allow it. Always use the heat range and gap size recommended for your specific engine.
How to determine the right spark plug for your model
To ensure you install the correct spark plugs, identify your engine code and model year, then verify Subaru’s official specification for that exact configuration. The process below outlines how to proceed.
- Find your engine code and year from the vehicle’s VIN plate or owner’s manual (examples include EJ, FB, FA families).
- Consult the official Subaru service documentation or owner’s manual for the exact spark plug type, heat range, and gap specified for your engine.
- Choose a plug that matches the exact specification (brand is usually NGK or Denso; avoid mixing incompatible heat ranges or tip types).
- Install with the recommended torque and gap. Many iridium/platinum plugs come pre-gapped; verify if your installation requires any adjustment.
- Plan replacement intervals based on plug type and driving conditions (iridium/platinum plugs often last longer, while copper plugs require more frequent changes). Replace all plugs at the same time to ensure even wear and performance.
In practice, the precise plug type is tightly tied to the engine design and market, so owners should rely on Subaru’s official specifications or a trained technician to avoid misfires, poor fuel economy, or starting issues.
Summary
Subarus use a range of spark plug types depending on the generation and engine family. Modern engines predominantly employ iridium or platinum plugs from NGK or Denso for longer life and reliable performance, while older EJ-series engines often used copper plugs. For any model year, always verify the exact heat range, gap, and brand recommended by Subaru and replace all plugs together for optimal results.
