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          Genuine VW/Audi 8E0121321 - Radiator Cap

          MPN: 8E0121321
          The Genuine VW/Audi 8E0121321 Radiator Cap ensures optimal pressure in your Audi's cooling system, preventing overheating and leaks. Designed for easy installation.
          0.0
          Vehicle Specific
          Check if this part fits your vehicle.
          • $36.16
          In stock

          Product Overview

          The Genuine VW/Audi Radiator Cap, part number 8E0121321, is an essential component for maintaining the performance and reliability of your Audi vehicle. Engineered to OEM standards, this radiator cap ensures an optimal fit and functions effectively within your vehicle's cooling system. Crafted from premium-grade materials, it is designed to withstand extreme temperatures and pressures, providing a secure seal that prevents leaks and maintains the proper pressure in the cooling system. Choose Genuine VW/Audi 8E0121321 for dependable performance and peace of mind every time you service your vehicle.

          Cross Reference Numbers

          This Genuine VW/Audi 8E0121321 is equivalent to or replaces the following part numbers: 8E0 121 321.

          Vehicle Compatibility

          This part fits some of the popular models below. For Fitment Confidence, please use the vehicle selector tool above to verify exact compatibility.

          • Audi A7 Quattro 3.0 V6 (2012)
          • Audi A6 Quattro 3.0 V6 (2011–2012)
          • Audi A6 Quattro 4.2 V8 (2011)
          • Audi S6 5.2 V10 (2011)
          • Audi A8 Quattro 4.2 V8 (2010–2012)
          • Audi S8 5.2 V10 (2008–2009)
          • Audi A4 3.0 V6 (2004–2006)
          • Audi S4 4.2 V8 (2004–2006)
          • Audi A6 3.2 V6 (2004–2011)
          • Audi A4 Quattro 1.8 L4 (2004–2006)

          This may also fit other applications. Please use the vehicle selector tool to verify fitment.

          Why Shop at eEuroparts.com?

          • Proven Expertise: Over 25 years of experience with European vehicles means we know your car inside and out.
          • Exclusive Kits That Fitâ„¢ - complete repair solutions with no guesswork
          • Fitment Confidence: Our accurate cataloging ensures you get the right part the first time.
          • Fast, Reliable Shipping: Orders ship quickly from our U.S.-based warehouses.
          • Transparent Pricing: Competitive prices with no hidden fees or surprise charges.
          • Established Trust: Serving the European auto community since 2000.

          Frequently Asked Questions

          What does the Genuine VW/Audi 8E0121321 Radiator Cap do?

          The radiator cap plays a crucial role in your vehicle's cooling system by maintaining the right pressure and sealing the reservoir. This ensures that coolant remains at optimal levels, preventing overheating and preserving engine performance.

          How do I know if my Radiator Cap needs replacement?

          Signs that your radiator cap may need replacement include coolant leaks, visible wear or damage on the cap, engine overheating, or warning lights indicating cooling system issues. Regular inspection can help prevent unexpected failures.

          Can I install the Genuine VW/Audi 8E0121321 myself?

          Yes, installation of the radiator cap is straightforward, making it a suitable option for DIY enthusiasts. Ensure the engine is cool before attempting to replace the cap to avoid burns or injuries.

          What are the symptoms of a faulty Radiator Cap?

          Common symptoms of a faulty radiator cap include coolant leaks, an overheating engine, and fluctuating temperature readings. If you see DTCs such as P0117 or P0128, it may indicate a failing radiator cap.

          Why should I choose Genuine VW/Audi for my Radiator Cap needs?

          Choosing Genuine VW/Audi ensures you receive a factory-correct replacement that restores safety and performance. Order Genuine VW/Audi 8E0121321 today for a reliable part that meets OEM specifications.

          Note: All information on this page and in the FAQ is for general reference only. Verify fitment and consult a professional as needed. eEuroparts.com is not responsible for incorrect part selection or installation.

            • eEuroparts SKU
              1392817
            • Weight
              0.16 lbs
            • Dimensions (L x W x H)
              4.382 x 1.4029 x 3.2321 in
            • Manufacturer Part #
              8E0121321
          • Brand
            Genuine VW/Audi
          • Manufacturer
            Genuine VW/Audi
          • MPN
            8E0121321
          • Part Type
            Radiator Cap
          • OE Part Numbers
            8E0 121 321, 8E0121321
          • Fitment
            • Fitment Type
              Vehicle Specific
          YearMakeModelSubmodelNotes
          2002AudiA4Base (1.8 L4 GAS)Aspiration: Turbocharged, Chassis: B6, Notes: 1.8 LITER
          2002AudiA4Base (3.0 V6 GAS)Chassis: B6, Notes: 3.0 LITER
          2002AudiA4 QuattroAvant (1.8 L4 GAS)Aspiration: Turbocharged, Chassis: B6, Notes: 1.8 LITER
          2002AudiA4 QuattroBase (1.8 L4 GAS)Aspiration: Turbocharged, Chassis: B6, Notes: 1.8 LITER
          2002AudiA4 QuattroAvant (3.0 V6 GAS)Chassis: B6, Notes: 3.0 LITER
          2002AudiA4 QuattroBase (3.0 V6 GAS)Chassis: B6, Notes: 3.0 LITER
          2002AudiA6Base (3.0 V6 GAS)Notes: 3.0 LITER V6
          2002AudiA6 QuattroBase (2.7 V6 GAS)Notes: 2.7 LITER V6, Notes: Location-Reservoir
          2002AudiA6 QuattroAvant (3.0 V6 GAS)Notes: 3.0 LITER V6
          2002AudiA6 QuattroBase (3.0 V6 GAS)Notes: 3.0 LITER V6, Notes: Location-Reservoir
          2002AudiAllroad QuattroBase (2.7 V6 GAS)
          2003AudiA4Base (1.8 L4 GAS)Aspiration: Turbocharged, Notes: 1.8 LITER, Chassis: B6
          2003AudiA4Cabriolet (1.8 L4 GAS)Aspiration: Turbocharged, Notes: 1.8 LITER, Chassis: B6
          2003AudiA4Base (3.0 V6 GAS)Notes: 3.0 LITER, Chassis: B6
          2003AudiA4Cabriolet (3.0 V6 GAS)Notes: 3.0 LITER, Chassis: B6
          2003AudiA4 QuattroAvant (1.8 L4 GAS)Aspiration: Turbocharged, Chassis: B6, Notes: 1.8 LITER
          2003AudiA4 QuattroBase (1.8 L4 GAS)Aspiration: Turbocharged, Chassis: B6, Notes: 1.8 LITER
          2003AudiA4 QuattroAvant (3.0 V6 GAS)Chassis: B6, Notes: 3.0 LITER
          2003AudiA4 QuattroBase (3.0 V6 GAS)Chassis: B6, Notes: 3.0 LITER
          2003AudiA6Base (3.0 V6 GAS)Notes: 3.0 LITER V6
          2003AudiA6 QuattroBase (2.7 V6 GAS)Notes: 2.7 LITER V6, Notes: Location-Reservoir
          2003AudiA6 QuattroAvant (3.0 V6 GAS)Notes: 3.0 LITER V6
          2003AudiA6 QuattroBase (3.0 V6 GAS)Notes: 3.0 LITER V6, Notes: Location-Reservoir
          2004AudiA4Base (1.8 L4 GAS)Aspiration: Turbocharged, Notes: 1.8 LITER, Chassis: B6
          2004AudiA4Cabriolet (1.8 L4 GAS)Aspiration: Turbocharged, Notes: 1.8 LITER, Chassis: B6
          2004AudiA4Base (3.0 V6 GAS)Notes: 3.0 LITER, Chassis: B6
          2004AudiA4Cabriolet (3.0 V6 GAS)Notes: 3.0 LITER, Chassis: B6
          2004AudiA4 QuattroAvant (1.8 L4 GAS)Aspiration: Turbocharged, Chassis: B6, Notes: 1.8 LITER
          2004AudiA4 QuattroBase (1.8 L4 GAS)Aspiration: Turbocharged, Chassis: B6, Notes: 1.8 LITER
          2004AudiA4 QuattroAvant (3.0 V6 GAS)Notes: 3.0 LITER, Chassis: B6
          2004AudiA4 QuattroBase (3.0 V6 GAS)Notes: 3.0 LITER, Chassis: B6
          2004AudiA4 QuattroCabriolet (3.0 V6 GAS)Notes: 3.0 LITER, Chassis: B6
          2004AudiA6Base (3.0 V6 GAS)Notes: 3.0 LITER V6
          2004AudiA6 QuattroBase (2.7 V6 GAS)Notes: 2.7 LITER V6, Notes: Location-Reservoir
          2004AudiA6 QuattroAvant (3.0 V6 GAS)Notes: 3.0 LITER V6
          2004AudiA6 QuattroBase (3.0 V6 GAS)Notes: 3.0 LITER V6, Notes: Location-Reservoir
          2004AudiA8 QuattroL (4.2 V8 GAS)Notes: 4.2 LITER 2004-06
          2004AudiS4Avant (4.2 V8 GAS)Notes: 4.2 LITER MAIN, Chassis: B6
          2004AudiS4Base (4.2 V8 GAS)Notes: 4.2 LITER MAIN, Chassis: B6
          2004AudiS4Cabriolet (4.2 V8 GAS)Notes: 4.2 LITER MAIN, Chassis: B6
          2005AudiA4Base (1.8 L4 GAS)Aspiration: Turbocharged, Notes: 1.8 LITER, Notes: Location-Reservoir, Chassis: B6
          2005AudiA4Cabriolet (1.8 L4 GAS)Aspiration: Turbocharged, Notes: 1.8 LITER, Chassis: B6
          2005AudiA4Base (3.0 V6 GAS)Notes: 3.0 LITER, Notes: Location-Reservoir, Chassis: B6
          2005AudiA4Cabriolet (3.0 V6 GAS)Notes: 3.0 LITER, Chassis: B6
          2005AudiA4 QuattroAvant (1.8 L4 GAS)Aspiration: Turbocharged, Chassis: B6, Notes: 1.8 LITER, Notes: Location-Reservoir
          2005AudiA4 QuattroBase (1.8 L4 GAS)Aspiration: Turbocharged, Chassis: B6, Notes: 1.8 LITER, Notes: Location-Reservoir
          2005AudiA4 QuattroAvant (3.0 V6 GAS)Notes: 3.0 LITER, Notes: Location-Reservoir, Chassis: B6
          2005AudiA4 QuattroBase (3.0 V6 GAS)Notes: 3.0 LITER, Notes: Location-Reservoir, Chassis: B6
          2005AudiA4 QuattroCabriolet (3.0 V6 GAS)Notes: 3.0 LITER, Chassis: B6
          2005AudiA6 QuattroBase (3.2 V6 GAS)Notes: 3.2 LITER
          2005AudiA6 QuattroBase (4.2 V8 GAS)Notes: 4.2 LITER MAIN
          2005AudiA8 QuattroBase (4.2 V8 GAS)Notes: 4.2 LITER 2004-06
          2005AudiA8 QuattroL (4.2 V8 GAS)Notes: 4.2 LITER 2004-06
          2005AudiA8 QuattroL (6.0 W12 GAS)Notes: 6.0 LITER PRIMARY
          2005AudiS4Avant (4.2 V8 GAS)
          2006AudiA4Cabriolet (1.8 L4 GAS)Aspiration: Turbocharged, Notes: 1.8 LITER
          2006AudiA4 QuattroCabriolet (3.0 V6 GAS)Notes: 3.0 LITER
          2006AudiA6Base (3.2 V6 GAS)Notes: 3.2 LITER
          2006AudiA6 QuattroAvant (3.2 V6 GAS)Notes: 3.2 LITER
          2006AudiA6 QuattroBase (3.2 V6 GAS)Notes: 3.2 LITER
          2006AudiA6 QuattroBase (4.2 V8 GAS)Notes: 4.2 LITER MAIN
          2006AudiA8 QuattroBase (4.2 V8 GAS)Notes: 4.2 LITER 2004-06
          2006AudiA8 QuattroL (4.2 V8 GAS)Notes: 4.2 LITER 2004-06
          2006AudiA8 QuattroL (6.0 W12 GAS)Notes: 6.0 LITER PRIMARY
          2007AudiA6Base (3.2 V6 GAS)Notes: 3.2 LITER
          2007AudiA6 QuattroAvant (3.2 V6 GAS)Notes: 3.2 LITER
          2007AudiA6 QuattroBase (3.2 V6 GAS)Notes: 3.2 LITER
          2007AudiA6 QuattroBase (4.2 V8 GAS)Notes: 4.2 LITER MAIN
          2007AudiA8 QuattroBase (4.2 V8 GAS)Notes: 4.2 LITER 2007-10
          2007AudiA8 QuattroL (4.2 V8 GAS)Notes: 4.2 LITER 2007-10
          2007AudiA8 QuattroL (6.0 W12 GAS)Notes: 6.0 LITER PRIMARY
          2008AudiA6Base (3.2 V6 GAS)Notes: 3.2 LITER
          2008AudiA6 QuattroAvant (3.2 V6 GAS)Notes: 3.2 LITER
          2008AudiA6 QuattroBase (3.2 V6 GAS)Notes: 3.2 LITER
          2008AudiA6 QuattroBase (4.2 V8 GAS)Notes: 4.2 LITER MAIN
          2008AudiA8 QuattroBase (4.2 V8 GAS)Notes: 4.2 LITER 2007-10
          2008AudiA8 QuattroL (4.2 V8 GAS)Notes: 4.2 LITER 2007-10
          2008AudiA8 QuattroL (6.0 W12 GAS)Notes: 6.0 LITER PRIMARY
          2009AudiA6Base (3.2 V6 GAS)Notes: 3.2 LITER
          2009AudiA6 QuattroAvant (3.0 V6 GAS)Notes: 3.0 LITER
          2009AudiA6 QuattroBase (3.0 V6 GAS)Notes: 3.0 LITER
          2009AudiA6 QuattroBase (4.2 V8 GAS)
          2009AudiA8 QuattroBase (4.2 V8 GAS)Notes: 4.2 LITER 2007-10
          2009AudiA8 QuattroL (4.2 V8 GAS)Notes: 4.2 LITER 2007-10
          2009AudiA8 QuattroL (6.0 W12 GAS)Notes: 6.0 LITER PRIMARY
          2010AudiA6Base (3.2 V6 GAS)Notes: 3.2 LITER
          2010AudiA6 QuattroAvant (3.0 V6 GAS)Notes: 3.0 LITER
          2010AudiA6 QuattroBase (3.0 V6 GAS)Notes: 3.0 LITER
          2010AudiA6 QuattroBase (4.2 V8 GAS)Notes: 4.2 LITER MAIN
          2010AudiA8 QuattroBase (4.2 V8 GAS)Notes: 4.2 LITER 2007-10
          2010AudiA8 QuattroL (4.2 V8 GAS)Notes: 4.2 LITER 2007-10
          2011AudiA6Base (3.2 V6 GAS)Notes: 3.2 LITER
          2011AudiA6 QuattroAvant (3.0 V6 GAS)Notes: 3.0 LITER
          2011AudiA6 QuattroBase (3.0 V6 GAS)Notes: 3.0 LITER
          2011AudiA6 QuattroBase (4.2 V8 GAS)Notes: 4.2 LITER MAIN
          2000AudiA6 QuattroBase (2.7 V6 GAS)Notes: 2.7 LITER V6
          2001AudiA6 QuattroBase (2.7 V6 GAS)Notes: 2.7 LITER V6
          2012AudiA6 QuattroPremium (3.0 V6 GAS)
          2012AudiA6 QuattroPremium Plus (3.0 V6 GAS)
          2012AudiA6 QuattroPrestige (3.0 V6 GAS)
          There are more vehicles this part is compatible with. Check if it fits your vehicle.
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          Warranty Overview

          At eEuroparts, 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, contact customer support via Chat or Contact Us.

          • 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 complete details, please see our full 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.

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