Subaru OEM Engine Coolant Thermostat Subaru Legacy GT 2006-2009 | 21210AA030

Overview

The Genuine Subaru OEM Thermostat & Seal Kit (Part #21210AA030) is the factory-replacement thermostat assembly designed specifically for the Subaru vehicles listed in the Fitment & Compatibility section below. Engineered to OEM specifications, this kit ensures your engine maintains optimal operating temperature for peak performance, fuel efficiency, and long-term engine health. If you're experiencing overheating, a stuck-open thermostat, or cooling system irregularities, replacing with this genuine Subaru part guarantees an exact fit and factory-level reliability.

Key Features & Benefits

• Genuine Subaru OEM Part – Manufactured to the exact factory specifications as the original thermostat; no modifications or adaptation required for installation.
• Precise Temperature Regulation – Opens and closes at the correct calibrated temperature to keep your engine within the ideal operating range, protecting against overheating and excessive warm-up times.
• Includes Sealing Gasket/O-Ring – Complete kit includes the thermostat and the necessary seal, eliminating the need to source a separate gasket and ensuring a leak-free installation.
• Exact-Fit Guarantee – Designed as a direct replacement for compatible Subaru models; drops in without drilling, cutting, or modification.
• Backed by Subaru Quality – Genuine Subaru parts meet stringent quality standards and are covered under Subaru's OEM parts warranty.
• Protects Engine Longevity – A properly functioning thermostat prevents coolant flow irregularities that can lead to head gasket stress, premature wear, and costly repairs.

What's Included

• 1x Genuine Subaru OEM Thermostat (Part #21210AA030)
• 1x Thermostat Housing Seal / O-Ring

Specifications

Fitment & Compatibility

Part #21210AA030 is a genuine Subaru OEM thermostat kit compatible with the following vehicles. Always verify your specific year, model, and trim using your VIN or the Subaru parts catalog to confirm compatibility before ordering.

2003-2006 Subaru Baja

2003-2013 Subaru Forester

2002-2007 Subaru Impreza

2009-2010 Subaru Impreza

2000-2007 Subaru Legacy

2009 Subaru Legacy

2015-2019 Subaru Legacy

2000-2007 Subaru Outback

2009 Subaru Outback

2015-2019 Subaru Outback

2004-2010 Subaru STI

2012-2021 Subaru STI

2002-2010 Subaru WRX

2012-2014 Subaru WRX

2019 Subaru WRX

Note: Use your VIN or consult the official Subaru parts catalog to confirm this part fits your specific vehicle before purchasing.

Installation

The Subaru OEM Thermostat & Seal Kit #21210AA030 is a direct bolt-on replacement for the factory thermostat on compatible Subaru models. Installation typically involves draining a portion of the coolant, removing the thermostat housing, swapping the thermostat and seal, and refilling/bleeding the cooling system. While a mechanically experienced DIYer can perform this service, professional installation by a Subaru-trained technician is recommended to ensure proper torque specifications and cooling system bleeding — particularly on turbocharged models. Always use fresh, Subaru-approved coolant when servicing the cooling system.