Ignition Coil & Iridium Spark Plugs for Subaru Legacy Outback (2015-2019) 2.5L

High-Energy Ignition Coil & Iridium Spark Plugs for 2015-2019 Subaru Legacy, Outback

Direct replacement ignition coils and iridium spark plugs restore proper spark timing and combustion efficiency for the 2.5L FB25 boxer engine.

The Stock Legacy, Outback Ignition Degradation

The factory ignition coils on the 2.5L FB25 engine are notoriously susceptible to thermal degradation over high-mileage heat cycles. Placed directly against the horizontal cylinder heads of the Subaru boxer configuration, the OEM coils endure localized heat soak that progressively breaks down internal epoxy potting. This thermal stress leads to micro-cracks in the coil housing, increasing electrical resistance and resulting in weak spark delivery. Simultaneously, standard spark plug electrodes erode over time, widening the gap and straining the ignition coils further. The combined failure of these components manifests as rough idling, persistent misfires under load, hesitation during acceleration, and decreased fuel economy.

The Engineering Solution

This comprehensive ignition kit directly resolves factory thermal limitations by utilizing upgraded ignition coils constructed with high-dielectric epoxy and reinforced polymer housings. These materials provide superior resistance to thermal shock and vibration inherent to the horizontally opposed engine layout, ensuring consistent voltage output without primary winding breakdown. Paired with exact-spec iridium spark plugs, the system maintains a highly concentrated, consistent spark across a precise gap. The iridium center electrode offers exceptionally high melting points and hardness, preventing gap widening and maintaining optimal combustion efficiency over an extended service life. This complete refresh restores factory drivability, eliminates ignition-related CEL codes, and optimizes the air-fuel burn rate for proper power delivery.

Technical Specifications

Compatibility

• 2015 Subaru Legacy 2.5L
• 2016 Subaru Legacy 2.5L
• 2017 Subaru Legacy 2.5L
• 2018 Subaru Legacy 2.5L
• 2019 Subaru Legacy 2.5L
• 2015 Subaru Outback 2.5L
• 2016 Subaru Outback 2.5L
• 2017 Subaru Outback 2.5L
• 2018 Subaru Outback 2.5L
• 2019 Subaru Outback 2.5L

The Subaru All-Weather Standard

Built to withstand the rugged, high-mileage demands of the Subaru symmetrical AWD platform, these ignition components restore the reliable, all-weather performance and smooth boxer operation your Legacy or Outback was engineered to deliver.