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AISIN THF-006 - Engine Coolant Thermostat
Product Overview
The AISIN THF-006 Engine Coolant Thermostat is designed to regulate your engine's temperature, ensuring optimal performance and efficiency. With OE-level quality and reliability, this thermostat guarantees a perfect fit for various Subaru models, including the Impreza, XV Crosstrek, and Legacy. Trust AISIN, a renowned brand in automotive parts, to deliver exceptional performance for your vehicle. Choose AISIN THF-006 for dependable performance and peace of mind every time you service your vehicle.
Cross Reference Numbers
This AISIN THF-006 is equivalent to or replaces the following part numbers: 21210-AA210, 21210AA210, 21210-AA200, 21210AA200, 21210-AA211, 21210AA211, 21210-AA220, 21210AA220, 21210-AA221, 21210AA221, THF006, THF-006, WV56FA-88, WV56FA88.
Vehicle Compatibility
- Subaru Impreza (2012-2014)
- Subaru XV Crosstrek (2013-2014)
- Subaru Legacy (2013-2023)
- Subaru Outback (2013-2023)
- Subaru Forester (2014-2018)
- Subaru WRX (2015-2023)
- Subaru Ascent (2019-2023)
This also fits other applications. Please use the vehicle selector tool to verify fitment.
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Frequently Asked Questions
What are the common symptoms of a faulty thermostat?
Common symptoms include engine overheating, fluctuating temperature gauge readings, and poor fuel economy. If you suspect an issue, consider replacing it with the AISIN THF-006.
How do I know if the AISIN THF-006 is compatible with my vehicle?
Check your vehicle's specifications and part numbers against the compatibility list provided. The AISIN THF-006 is designed for various Subaru models for precise fitment.
What DTCs are related to the thermostat?
Common Diagnostic Trouble Codes related to thermostat issues include P0128 and P0116. If you encounter these codes, replacing the thermostat with AISIN THF-006 may resolve the issue.
How often should I replace my engine coolant thermostat?
It's generally recommended to replace your thermostat every 60,000 to 100,000 miles or if you notice any symptoms of malfunction. For a reliable replacement, choose AISIN THF-006.
Is the gasket included with the AISIN THF-006?
Yes, the AISIN THF-006 includes a gasket to ensure a proper seal and optimal performance.
Order AISIN THF-006 today for a factory-correct replacement that restores safety and performance.
- BrandAISIN
- ManufacturerAISIN
- MPNTHF-006
- FeaturesBypass Flange Diameter : 28.0
Design : Bottom By-Pass
Flange Height : 36.0
Gasket Or Seal Included : Yes
Includes Jiggle Pin Check Valve : Yes
Material : Brass
Material : Stainless Steel
Sealing Flange Outside Diameter : 56.0
Start to Open Temperature : 88.0 - OE Part Numbers21210-AA210, 21210AA210, 21210-AA200, 21210AA200, 21210-AA211, 21210AA211, 21210-AA220, 21210AA220, 21210-AA221, 21210AA221
- Cross Reference NumbersTHF006, THF-006, WV56FA-88, WV56FA88
- Part TypeEngine Coolant Thermostat
- Fitment
- Fitment TypeVehicle Specific
| Year | Make | Model | Submodel | Notes |
|---|---|---|---|---|
| 2013 | Subaru | Legacy | 2.5i (2.5 H4 GAS) | Notes: Includes Thermostat Seal, 88°C, 88°C (190°F) OE Temp Thermostat |
| 2013 | Subaru | Legacy | 2.5i Limited (2.5 H4 GAS) | Notes: Includes Thermostat Seal, 88°C, 88°C (190°F) OE Temp Thermostat |
| 2013 | Subaru | Legacy | 2.5i Premium (2.5 H4 GAS) | Notes: Includes Thermostat Seal, 88°C, 88°C (190°F) OE Temp Thermostat |
| 2013 | Subaru | Outback | 2.5i (2.5 H4 GAS) | Notes: Includes Thermostat Seal, 88°C, 88°C (190°F) OE Temp Thermostat |
| 2013 | Subaru | Outback | 2.5i Limited (2.5 H4 GAS) | Notes: Includes Thermostat Seal, 88°C, 88°C (190°F) OE Temp Thermostat |
| 2013 | Subaru | Outback | 2.5i Premium (2.5 H4 GAS) | Notes: Includes Thermostat Seal, 88°C, 88°C (190°F) OE Temp Thermostat |
| 2013 | Subaru | XV Crosstrek | Limited (2.0 H4 GAS) | Position: Lower, Transmission Control: Manual, Transmission Control: Automatic CVT, Notes: Includes Thermostat Seal, 88°C, 88°C (190°F) OE Temp Thermostat |
| 2013 | Subaru | XV Crosstrek | Premium (2.0 H4 GAS) | Position: Lower, Transmission Control: Manual, Transmission Control: Automatic CVT, Notes: Includes Thermostat Seal, 88°C, 88°C (190°F) OE Temp Thermostat |
| 2013 | Subaru | Impreza | Base (2.0 H4 GAS) | Notes: Includes Thermostat Seal, 88°C, 88°C (190°F) OE Temp Thermostat |
| 2013 | Subaru | Impreza | Limited (2.0 H4 GAS) | Notes: Includes Thermostat Seal, 88°C, 88°C (190°F) OE Temp Thermostat |
| 2013 | Subaru | Impreza | Premium (2.0 H4 GAS) | Notes: Includes Thermostat Seal, 88°C, 88°C (190°F) OE Temp Thermostat |
| 2013 | Subaru | Impreza | Sport Limited (2.0 H4 GAS) | Notes: Includes Thermostat Seal, 88°C, 88°C (190°F) OE Temp Thermostat |
| 2013 | Subaru | Impreza | Sport Premium (2.0 H4 GAS) | Notes: Includes Thermostat Seal, 88°C, 88°C (190°F) OE Temp Thermostat |
| 2014 | Subaru | Outback | 2.5i (2.5 H4 GAS) | Notes: Includes Thermostat Seal, 88°C, 88°C (190°F) OE Temp Thermostat |
| 2014 | Subaru | Outback | 2.5i Limited (2.5 H4 GAS) | Notes: Includes Thermostat Seal, 88°C, 88°C (190°F) OE Temp Thermostat |
| 2014 | Subaru | Outback | 2.5i Premium (2.5 H4 GAS) | Notes: Includes Thermostat Seal, 88°C, 88°C (190°F) OE Temp Thermostat |
| 2014 | Subaru | Legacy | 2.5i (2.5 H4 GAS) | Notes: Includes Thermostat Seal, 88°C, 88°C (190°F) OE Temp Thermostat |
| 2014 | Subaru | Legacy | 2.5i Limited (2.5 H4 GAS) | Notes: Includes Thermostat Seal, 88°C, 88°C (190°F) OE Temp Thermostat |
| 2014 | Subaru | Legacy | 2.5i Premium (2.5 H4 GAS) | Notes: Includes Thermostat Seal, 88°C, 88°C (190°F) OE Temp Thermostat |
| 2014 | Subaru | Legacy | 2.5i Sport (2.5 H4 GAS) | Notes: Includes Thermostat Seal, 88°C, 88°C (190°F) OE Temp Thermostat |
| 2014 | Subaru | XV Crosstrek | Limited (2.0 H4 GAS) | Position: Lower, Transmission Control: Manual, Transmission Control: Automatic CVT, Notes: Includes Thermostat Seal, 88°C, 88°C (190°F) OE Temp Thermostat |
| 2014 | Subaru | XV Crosstrek | Premium (2.0 H4 GAS) | Position: Lower, Transmission Control: Manual, Transmission Control: Automatic CVT, Notes: Includes Thermostat Seal, 88°C, 88°C (190°F) OE Temp Thermostat |
| 2014 | Subaru | XV Crosstrek | Hybrid (2.0 H4 FHEV) | Position: Lower, Transmission Control: Manual, Transmission Control: Automatic CVT, Notes: Includes Thermostat Seal, 88°C, 88°C (190°F) OE Temp Thermostat |
| 2014 | Subaru | XV Crosstrek | Hybrid Touring (2.0 H4 FHEV) | Position: Lower, Transmission Control: Manual, Transmission Control: Automatic CVT, Notes: Includes Thermostat Seal, 88°C, 88°C (190°F) OE Temp Thermostat |
| 2014 | Subaru | Impreza | Base (2.0 H4 GAS) | Notes: Includes Thermostat Seal, 88°C, 88°C (190°F) OE Temp Thermostat |
| 2014 | Subaru | Impreza | Limited (2.0 H4 GAS) | Notes: Includes Thermostat Seal, 88°C, 88°C (190°F) OE Temp Thermostat |
| 2014 | Subaru | Impreza | Premium (2.0 H4 GAS) | Notes: Includes Thermostat Seal, 88°C, 88°C (190°F) OE Temp Thermostat |
| 2014 | Subaru | Impreza | Sport Limited (2.0 H4 GAS) | Notes: Includes Thermostat Seal, 88°C, 88°C (190°F) OE Temp Thermostat |
| 2014 | Subaru | Impreza | Sport Premium (2.0 H4 GAS) | Notes: Includes Thermostat Seal, 88°C, 88°C (190°F) OE Temp Thermostat |
| 2014 | Subaru | Forester | 2.0XT Premium (2.0 H4 GAS) | Notes: Includes Thermostat Seal, 88°C, 88°C (190°F) OE Temp Thermostat |
| 2014 | Subaru | Forester | 2.0XT Touring (2.0 H4 GAS) | Notes: Includes Thermostat Seal, 88°C, 88°C (190°F) OE Temp Thermostat |
| 2012 | Subaru | Impreza | Base (2.0 H4 GAS) | Notes: Includes Thermostat Seal, 88°C, 88°C (190°F) OE Temp Thermostat |
| 2012 | Subaru | Impreza | Limited (2.0 H4 GAS) | Notes: Includes Thermostat Seal, 88°C, 88°C (190°F) OE Temp Thermostat |
| 2012 | Subaru | Impreza | Premium (2.0 H4 GAS) | Notes: Includes Thermostat Seal, 88°C, 88°C (190°F) OE Temp Thermostat |
| 2012 | Subaru | Impreza | Sport Limited (2.0 H4 GAS) | Notes: Includes Thermostat Seal, 88°C, 88°C (190°F) OE Temp Thermostat |
| 2012 | Subaru | Impreza | Sport Premium (2.0 H4 GAS) | Notes: Includes Thermostat Seal, 88°C, 88°C (190°F) OE Temp Thermostat |
| 2015 | Subaru | WRX | Base (2.0 H4 GAS) | Engine: FA20F, Notes: Includes Thermostat Seal, 88°C, 88°C (190°F) OE Temp Thermostat |
| 2015 | Subaru | WRX | Limited (2.0 H4 GAS) | Engine: FA20F, Notes: Includes Thermostat Seal, 88°C, 88°C (190°F) OE Temp Thermostat |
| 2015 | Subaru | WRX | Premium (2.0 H4 GAS) | Engine: FA20F, Notes: Includes Thermostat Seal, 88°C, 88°C (190°F) OE Temp Thermostat |
| 2015 | Subaru | Forester | 2.0XT Premium (2.0 H4 GAS) | Notes: Includes Thermostat Seal, 88°C, 88°C (190°F) OE Temp Thermostat |
| 2015 | Subaru | Forester | 2.0XT Touring (2.0 H4 GAS) | Notes: Includes Thermostat Seal, 88°C, 88°C (190°F) OE Temp Thermostat |
| 2016 | Subaru | Forester | 2.0XT Premium (2.0 H4 GAS) | Notes: Includes Thermostat Seal, 88°C |
| 2016 | Subaru | Forester | 2.0XT Touring (2.0 H4 GAS) | Notes: Includes Thermostat Seal, 88°C |
| 2016 | Subaru | WRX | Base (2.0 H4 GAS) | Notes: Includes Thermostat Seal, 88°C |
| 2016 | Subaru | WRX | Limited (2.0 H4 GAS) | Notes: Includes Thermostat Seal, 88°C |
| 2016 | Subaru | WRX | Premium (2.0 H4 GAS) | Notes: Includes Thermostat Seal, 88°C |
| 2017 | Subaru | Forester | 2.0XT Premium (2.0 H4 GAS) | Notes: Includes Thermostat Seal, 88°C |
| 2017 | Subaru | Forester | 2.0XT Touring (2.0 H4 GAS) | Notes: Includes Thermostat Seal, 88°C |
| 2017 | Subaru | WRX | Base (2.0 H4 GAS) | Notes: Includes Thermostat Seal, 88°C |
| 2017 | Subaru | WRX | Limited (2.0 H4 GAS) | Notes: Includes Thermostat Seal, 88°C |
| 2017 | Subaru | WRX | Premium (2.0 H4 GAS) | Notes: Includes Thermostat Seal, 88°C |
| 2018 | Subaru | WRX | Base (2.0 H4 GAS) | Notes: Includes Thermostat Seal, 88°C |
| 2018 | Subaru | WRX | Limited (2.0 H4 GAS) | Notes: Includes Thermostat Seal, 88°C |
| 2018 | Subaru | WRX | Premium (2.0 H4 GAS) | Notes: Includes Thermostat Seal, 88°C |
| 2018 | Subaru | Forester | 2.0XT Premium (2.0 H4 GAS) | Notes: Includes Thermostat Seal, 88°C |
| 2018 | Subaru | Forester | 2.0XT Touring (2.0 H4 GAS) | Notes: Includes Thermostat Seal, 88°C |
| 2019 | Subaru | Ascent | Base (2.4 H4 GAS) | Position: Front, Notes: Includes Thermostat Seal, 88°C |
| 2019 | Subaru | Ascent | Limited (2.4 H4 GAS) | Position: Front, Notes: Includes Thermostat Seal, 88°C |
| 2019 | Subaru | Ascent | Premium (2.4 H4 GAS) | Position: Front, Notes: Includes Thermostat Seal, 88°C |
| 2019 | Subaru | Ascent | Touring (2.4 H4 GAS) | Position: Front, Notes: Includes Thermostat Seal, 88°C |
| 2019 | Subaru | WRX | Base (2.0 H4 GAS) | Notes: Includes Thermostat Seal, 88°C |
| 2019 | Subaru | WRX | Limited (2.0 H4 GAS) | Notes: Includes Thermostat Seal, 88°C |
| 2019 | Subaru | WRX | Premium (2.0 H4 GAS) | Notes: Includes Thermostat Seal, 88°C |
| 2020 | Subaru | Legacy | Limited XT (2.4 H4 GAS) | Position: Lower, Notes: Includes Thermostat Seal, 88°C |
| 2020 | Subaru | Legacy | Touring XT (2.4 H4 GAS) | Position: Lower, Notes: Includes Thermostat Seal, 88°C |
| 2020 | Subaru | Ascent | Base (2.4 H4 GAS) | Position: Front, Notes: Includes Thermostat Seal, 88°C |
| 2020 | Subaru | Ascent | Limited (2.4 H4 GAS) | Position: Front, Notes: Includes Thermostat Seal, 88°C |
| 2020 | Subaru | Ascent | Premium (2.4 H4 GAS) | Position: Front, Notes: Includes Thermostat Seal, 88°C |
| 2020 | Subaru | Ascent | Touring (2.4 H4 GAS) | Position: Front, Notes: Includes Thermostat Seal, 88°C |
| 2020 | Subaru | Outback | Limited XT (2.4 H4 GAS) | Position: Lower, Notes: Includes Thermostat Seal, 88°C |
| 2020 | Subaru | Outback | Onyx Edition XT (2.4 H4 GAS) | Position: Lower, Notes: Includes Thermostat Seal, 88°C |
| 2020 | Subaru | Outback | Touring XT (2.4 H4 GAS) | Position: Lower, Notes: Includes Thermostat Seal, 88°C |
| 2020 | Subaru | WRX | Base (2.0 H4 GAS) | Notes: Includes Thermostat Seal, 88°C |
| 2020 | Subaru | WRX | Limited (2.0 H4 GAS) | Notes: Includes Thermostat Seal, 88°C |
| 2020 | Subaru | WRX | Premium (2.0 H4 GAS) | Notes: Includes Thermostat Seal, 88°C |
| 2021 | Subaru | Outback | Limited XT (2.4 H4 GAS) | Position: Lower, Notes: Includes Thermostat Seal, 88°C |
| 2021 | Subaru | Outback | Onyx Edition XT (2.4 H4 GAS) | Position: Lower, Notes: Includes Thermostat Seal, 88°C |
| 2021 | Subaru | Outback | Touring XT (2.4 H4 GAS) | Position: Lower, Notes: Includes Thermostat Seal, 88°C |
| 2021 | Subaru | Legacy | Limited XT (2.4 H4 GAS) | Position: Lower, Notes: Includes Thermostat Seal, 88°C |
| 2021 | Subaru | Legacy | Touring XT (2.4 H4 GAS) | Position: Lower, Notes: Includes Thermostat Seal, 88°C |
| 2021 | Subaru | Ascent | Base (2.4 H4 GAS) | Position: Front, Notes: Includes Thermostat Seal, 88°C |
| 2021 | Subaru | Ascent | Limited (2.4 H4 GAS) | Position: Front, Notes: Includes Thermostat Seal, 88°C |
| 2021 | Subaru | Ascent | Premium (2.4 H4 GAS) | Position: Front, Notes: Includes Thermostat Seal, 88°C |
| 2021 | Subaru | Ascent | Touring (2.4 H4 GAS) | Position: Front, Notes: Includes Thermostat Seal, 88°C |
| 2021 | Subaru | WRX | Base (2.0 H4 GAS) | Position: Lower, Notes: Includes Thermostat Seal, 88°C |
| 2021 | Subaru | WRX | Limited (2.0 H4 GAS) | Position: Lower, Notes: Includes Thermostat Seal, 88°C |
| 2021 | Subaru | WRX | Premium (2.0 H4 GAS) | Position: Lower, Notes: Includes Thermostat Seal, 88°C |
| 2022 | Subaru | Ascent | Base (2.4 H4 GAS) | Position: Front, Notes: Includes Thermostat Seal, 88°C |
| 2022 | Subaru | Ascent | Limited (2.4 H4 GAS) | Position: Front, Notes: Includes Thermostat Seal, 88°C |
| 2022 | Subaru | Ascent | Onyx Edition (2.4 H4 GAS) | Position: Front, Notes: Includes Thermostat Seal, 88°C |
| 2022 | Subaru | Ascent | Premium (2.4 H4 GAS) | Position: Front, Notes: Includes Thermostat Seal, 88°C |
| 2022 | Subaru | Ascent | Touring (2.4 H4 GAS) | Position: Front, Notes: Includes Thermostat Seal, 88°C |
| 2022 | Subaru | Outback | Limited XT (2.4 H4 GAS) | Notes: Includes Thermostat Seal, 88°C |
| 2022 | Subaru | Outback | Onyx Edition XT (2.4 H4 GAS) | Notes: Includes Thermostat Seal, 88°C |
| 2022 | Subaru | Outback | Touring XT (2.4 H4 GAS) | Notes: Includes Thermostat Seal, 88°C |
| 2022 | Subaru | Outback | Wilderness (2.4 H4 GAS) | Notes: Includes Thermostat Seal, 88°C |
| 2022 | Subaru | Legacy | Limited XT (2.4 H4 GAS) | Notes: Includes Thermostat Seal, 88°C |
| 2022 | Subaru | Legacy | Touring XT (2.4 H4 GAS) | Notes: Includes Thermostat Seal, 88°C |
| 2022 | Subaru | WRX | Base (2.4 H4 GAS) | Position: Lower, Notes: Includes Thermostat Seal, 88°C |
| 2022 | Subaru | WRX | GT (2.4 H4 GAS) | Position: Lower, Notes: Includes Thermostat Seal, 88°C |
Warranty Overview
At Newparts, we stand behind the quality of the products we sell. Every part we offer is backed by a warranty designed to give you peace of mind and protect your investment.
Standard Warranty – Most Parts
Coverage: 2 years or 24,000 miles (whichever comes first) from purchase date.
Protection: Defects in materials or workmanship under normal personal use.
Eligibility: Applies only to the original purchaser and the vehicle where the part was first installed.
Exclusions:
Wear-and-tear items (brake pads, filters, bulbs, wipers, etc.)
Commercial, fleet, rideshare, off-road, or racing use
Improper installation, misuse, accidents, or modifications
Not Covered: Labor, shipping, towing, or incidental costs.
Bison Performance Warranty – Our House Brand
Coverage: Limited Lifetime Warranty for as long as you own your vehicle.
Applies To: All products sold under the Bison Performance label.
Premium Protection: Goes beyond our standard warranty — if it’s a Bison product, the 2-year/24k mile limit is replaced with lifetime coverage.
Exclusions: Same as the standard warranty (normal wear, commercial use, improper installation, etc.).
What’s Included: Replacement of the defective product (labor and shipping excluded).
Warranty Claim Requirements
To keep claims fast and fair, we require:
Proof of purchase (invoice or order confirmation).
Photos or videos showing the defective part, order number, date, VIN, and odometer reading.
Diagnostic reports or part returns for non-visible issues may be requested.
Claims must be truthful, properly documented, and reflect normal consumer use.
Buy With Confidence: We back our products because we believe in their quality, with a transparent, customer-first warranty process you can trust. And with Bison Performance products, you’ll enjoy Limited Lifetime protection—an assurance few brands can match.
For full details and exclusions, please see our complete Warranty Terms & Conditions.
This summary is for convenience only. For full warranty coverage details, exclusions, and requirements, see our official Warranty Terms & Conditions. In case of conflict, the full policy governs.
Return Policy Overview
Most parts can be returned within 30 days of delivery if unused, uninstalled, and in original packaging.
To start a return, use our Return Portal or contact support.
Restocking fee: Up to 20% may apply for certain orders (buyer’s remorse, order errors, or special-order items)
Refunds: Issued to your original payment method within 3–5 business days after inspection
Exchanges: Not automatic — please return and reorder
Replacements: May be approved for incorrect or defective items reported within 7 days
Not returnable:
Used or installed parts
Electrical components
Opened filter kits, gaskets, or contaminated items
Final sale or custom orders
Important Notes:
Return shipping is your responsibility unless we made a verified error
Fitment is the customer’s responsibility (we can assist, but do not guarantee)
Country of origin may vary and is not grounds for return
For complete details, please see our full Return Policy.
This Returns summary is provided for convenience only. All returns, refunds, and exchanges are subject to the complete Returns Policy. In the event of any conflict, the full policy governs.
Fast, Reliable Shipping — Straight to Your Door
We ship most orders the same day when placed before 2 PM CST (Monday–Friday). Our main warehouse is just east of Nashville, TN, and we also ship from multiple locations nationwide to get your order to you as quickly as possible.
We use trusted carriers like UPS, FedEx, and USPS.
Tracking info is emailed to you as soon as your order ships.
Delivery estimates at checkout are based on carrier data, but not guaranteed.
Need help with a shipment?
If your order is missing, damaged, or incorrect, just let us know within 5 days of delivery. We’ll walk you through the quick claim process — including a few photos to help us make things right.
For full details, please see our complete Shipping Policy.
This Shipping summary is provided for convenience only. Delivery times, carrier terms, fees, restrictions, risk of loss, and other details are governed by our complete Shipping Policy. In the event of any conflict, the full policy governs.
















