Best Spark Plugs for Subaru Outback and Forester: Boxer Engine Essentials

Subaru's horizontally-opposed "boxer" engines are unique — and they have specific spark plug requirements. The 2.5L naturally aspirated and 2.5L turbocharged EJ and FA-series engines are common in Outback and Forester models.

Why Boxer Engines Are Picky About Plugs

Subaru's flat-four layout means the plugs on one bank point sideways. Heat distribution is slightly different from inline engines, making plug quality and correct heat range especially important.

Best Spark Plugs for the 2.5L Naturally Aspirated

NGK Laser Iridium plugs (DILKAR7A11) are the factory-fit plug for most naturally aspirated Subaru engines. These are pre-gapped and ready to install. The iridium tip ensures the 60,000-mile OEM service interval.

Turbocharged Subaru (XT Models)

For turbocharged Outback XT and Forester XT models, NGK's OEM-spec iridium plugs are the safe choice. Running the wrong heat range on a turbo Subaru can cause detonation — stick with OEM specification.

Plug Change Difficulty

Subaru spark plug changes are not the easiest DIY job — the boxer layout requires removing some intake components on certain models. However, with the right tools it's a rewarding job that saves significant money over the dealer.

Shop Subaru spark plugs at Texan Supply with free shipping.