Koyo Radiator – 2008–2015 Subaru WRX / STI | 2005–2009 Subaru Legacy GT 2.5L | Manual Transmission | w/ Filler Neck

Keep your turbocharged Subaru running cool with this Koyo performance radiator. A direct-fit upgrade over the factory unit, this radiator is engineered specifically for manual transmission WRX, STI, and Legacy GT applications — featuring a filler neck provision and application-specific pipe sizing for a clean, bolt-in installation.

Koyo is one of Japan’s most respected OEM and aftermarket radiator manufacturers, trusted by enthusiasts and professional teams worldwide for superior cooling performance and build quality.

Key Features

• Direct OEM Replacement: Bolt-in fitment for manual transmission WRX, STI, and Legacy GT models — no modifications required
• Filler Neck Included: Features an integrated filler neck provision (adapter thread M14x1.25)
• Application-Specific Pipe Sizing: STI uses 8mm pipe; WRX uses 13mm pipe — verify your fitment before ordering
• Superior Cooling Capacity: Koyo’s high-efficiency core design improves heat dissipation over the factory radiator
• OEM-Grade Quality: Manufactured by Koyo, a trusted OEM supplier to major Japanese automakers

Fitment

• 2008–2015 Subaru WRX (Manual Transmission) — 13mm pipe
• 2008–2015 Subaru WRX STI (Manual Transmission) — 8mm pipe
• 2005–2009 Subaru Legacy GT 2.5L (Manual Transmission, NA & Turbo)
• Adapter provision thread: M14x1.25

Note: Manual transmission only — not compatible with automatic transmission models. Verify pipe size compatibility (STI: 8mm / WRX: 13mm) before ordering. Professional installation recommended.