Genuine Audi Radiator Cap

Cooling Radiator Cap

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9 Radiator Caps found

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Audi Auxiliary Radiator Cap Part Number: 4D0-133-335
$21.49 MSRP: $34.38
You Save: $12.89 (38%)
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Product Specifications
- Other Name: Cap; Radiator Cap
Fits the following Audi Models:
- A6 Quattro | 2019-2023 | Premium, Premium Plus, Prestige | 6 Cyl 3.0 L MILD HYBRID EV-GAS (MHEV)
- A6 allroad | 2020-2023 | Premium Plus, Prestige | 6 Cyl 3.0 L MILD HYBRID EV-GAS (MHEV)
- A7 Sportback | 2019-2023 | Premium, Premium Plus, Prestige | 4 Cyl 2.0 L PLUG-IN HYBRID EV-GAS (PHEV), 6 Cyl 3.0 L MILD HYBRID EV-GAS (MHEV)
- A8 Quattro | 2019-2023, 2013-2016 | Base, L, L Plug-In Hybrid, L TDI | 6 Cyl 3.0 L DIESEL, 6 Cyl 3.0 L GAS, 6 Cyl 3.0 L MILD HYBRID EV-GAS (MHEV), 6 Cyl 3.0 L PLUG-IN HYBRID EV-GAS (PHEV), 8 Cyl 4.0 L MILD HYBRID EV-GAS (MHEV)
- Q5 | 2021-2023 | Premium, Premium Plus, Prestige | 4 Cyl 2.0 L MILD HYBRID EV-GAS (MHEV)
- Q5 PHEV | 2020-2023 | Premium, Premium Plus, Prestige | 4 Cyl 2.0 L PLUG-IN HYBRID EV-GAS (PHEV)
- Q7 | 2020-2023 | Premium, Premium Plus, Prestige | 6 Cyl 3.0 L MILD HYBRID EV-GAS (MHEV)
- Q8 | 2019-2023 | Premium, Premium Plus, Prestige | 6 Cyl 3.0 L MILD HYBRID EV-GAS (MHEV)
- RS Q8 | 2020-2023 | Base | 8 Cyl 4.0 L MILD HYBRID EV-GAS (MHEV)
- RS5 | 2021-2024, 2019 | Base | 6 Cyl 2.9 L GAS
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Audi Reservoir Cap Part Number: 3B0-121-321
$24.74 MSRP: $39.59
You Save: $14.85 (38%)
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Product Specifications
- Other Name: Cover; Cap, Radiator Cap
Fits the following Audi Models:
- A3 | 2006-2013 | Base, TDI | 4 Cyl 2.0 L DIESEL, 4 Cyl 2.0 L GAS
- A3 Quattro | 2006-2013 | Base | 4 Cyl 2.0 L GAS, 6 Cyl 3.2 L GAS
- A3 Sportback e-tron | 2016-2017 | Premium, Premium Plus, Prestige | 4 Cyl 1.4 L PLUG-IN HYBRID EV-GAS (PHEV)
- A4 | 2005-2016, 1998-2001 | Avant, Base, Cabriolet, Premium, Premium Plus, Prestige | 4 Cyl 1.8 L GAS, 4 Cyl 2.0 L GAS, 6 Cyl 2.8 L GAS, 6 Cyl 3.2 L GAS
- A4 Quattro | 2005-2016, 1998-2001 | Avant, Base, Cabriolet, Premium, Premium Plus, Prestige | 4 Cyl 1.8 L GAS, 4 Cyl 2.0 L FLEX, 4 Cyl 2.0 L GAS, 6 Cyl 2.8 L GAS, 6 Cyl 3.2 L GAS
- A5 | 2010-2014 | Cabriolet | 4 Cyl 2.0 L GAS
- A5 Quattro | 2008-2017 | Base, Cabriolet, Premium, Premium Plus, Prestige, Sport | 4 Cyl 2.0 L FLEX, 4 Cyl 2.0 L GAS, 6 Cyl 3.2 L GAS
- A6 | 2012-2018, 1998-2001 | Base, Premium, Premium Plus, Sport | 4 Cyl 2.0 L GAS, 6 Cyl 2.8 L GAS
- A6 Quattro | 2012-2018, 1998-2004 | Avant, Base, Competition, Premium, Premium Plus, Prestige, Sport, TDI Premium Plus, TDI Prestige | 4 Cyl 2.0 L GAS, 6 Cyl 2.8 L GAS, 6 Cyl 3.0 L DIESEL, 6 Cyl 3.0 L GAS, 8 Cyl 4.2 L GAS
- A7 Quattro | 2012-2018 | Base, Competition, Premium Plus, Prestige, TDI Premium Plus, TDI Prestige | 6 Cyl 3.0 L DIESEL, 6 Cyl 3.0 L GAS
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Audi Reservoir Cap Part Number: 8E0-121-321
$34.86 MSRP: $55.78
You Save: $20.92 (38%)
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Product Specifications
- Other Name: Cover; Cap
Fits the following Audi Models:
- A4 | 2002-2006 | Base, Cabriolet | 4 Cyl 1.8 L GAS, 6 Cyl 3.0 L GAS
- A4 Quattro | 2002-2006 | Avant, Base, Cabriolet | 4 Cyl 1.8 L GAS, 6 Cyl 3.0 L GAS
- A6 | 2006-2011, 2002-2004 | Base | 6 Cyl 3.0 L GAS, 6 Cyl 3.2 L GAS
- A6 Quattro | 2000-2011 | Avant, Base | 6 Cyl 2.7 L GAS, 6 Cyl 3.0 L GAS, 6 Cyl 3.2 L GAS, 8 Cyl 4.2 L GAS
- A8 Quattro | 2004-2010 | Base, L | 12 Cyl 6.0 L GAS, 8 Cyl 4.2 L GAS
- S4 | 2004-2006 | Avant, Base, Cabriolet | 8 Cyl 4.2 L GAS
- S6 | 2007-2011 | Base | 10 Cyl 5.2 L GAS
- S8 | 2007-2009 | Base | 10 Cyl 5.2 L GAS
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Audi Reservoir Cap Part Number: 420-121-321
$233.24 MSRP: $326.66
You Save: $93.42 (29%)
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Product Specifications
- Other Name: Cover; Cap
Fits the following Audi Models:
- R8 | 2014-2015, 2008-2012 | Base, GT, GT Spyder, Plus, Spyder | 10 Cyl 5.2 L GAS, 8 Cyl 4.2 L GAS
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Audi Reservoir Cap Part Number: 4B3-121-321
$42.35 MSRP: $58.34
You Save: $15.99 (28%)
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Product Specifications
- Other Name: Cover; Cap
Fits the following Audi Models:
- R8 | 2014-2015 | Spyder | 10 Cyl 5.2 L GAS, 8 Cyl 4.2 L GAS
- RS5 | 2013-2015 | Base, Cabriolet | 8 Cyl 4.2 L GAS
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Audi Reservoir Cap Part Number: 4M0-121-321-Q
$43.55 MSRP: $59.98
You Save: $16.43 (28%)
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Product Specifications
- Other Name: Cap; Reservoir Cap
- Replaces: 4M0-121-321-J, 4M0-121-321-K, 4M0-121-321-H
Fits the following Audi Models:
- A4 | 2017-2020 | Premium, Premium Plus, Prestige, Titanium | 4 Cyl 2.0 L GAS
- A4 Quattro | 2017-2021 | Premium, Premium Plus, Prestige, Ultra sport | 4 Cyl 2.0 L GAS, 4 Cyl 2.0 L MILD HYBRID EV-GAS (MHEV)
- A4 allroad | 2017-2020 | Premium, Premium Plus, Prestige | 4 Cyl 2.0 L GAS
- A5 Quattro | 2018-2023 | Premium, Premium Plus, Prestige | 4 Cyl 2.0 L GAS, 4 Cyl 2.0 L MILD HYBRID EV-GAS (MHEV)
- A5 Sportback | 2018-2023 | Premium, Premium Plus, Prestige | 4 Cyl 2.0 L GAS, 4 Cyl 2.0 L MILD HYBRID EV-GAS (MHEV)
- A6 Quattro | 2019-2023 | Premium, Premium Plus, Prestige | 4 Cyl 2.0 L GAS, 4 Cyl 2.0 L MILD HYBRID EV-GAS (MHEV), 6 Cyl 3.0 L MILD HYBRID EV-GAS (MHEV)
- A6 allroad | 2020-2023 | Premium Plus, Prestige | 6 Cyl 3.0 L MILD HYBRID EV-GAS (MHEV)
- A7 Sportback | 2019-2023 | Premium, Premium Plus, Prestige | 4 Cyl 2.0 L PLUG-IN HYBRID EV-GAS (PHEV), 6 Cyl 3.0 L MILD HYBRID EV-GAS (MHEV)
- A8 Quattro | 2019-2023 | L, L Plug-In Hybrid | 6 Cyl 3.0 L MILD HYBRID EV-GAS (MHEV), 6 Cyl 3.0 L PLUG-IN HYBRID EV-GAS (PHEV), 8 Cyl 4.0 L MILD HYBRID EV-GAS (MHEV)
- Q5 | 2018-2023 | Premium, Premium Plus, Prestige, Titanium Premium, Titanium Premium Plus, Titanium Prestige | 4 Cyl 2.0 L GAS, 4 Cyl 2.0 L MILD HYBRID EV-GAS (MHEV)
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Audi Cap Part Number: 4KE-121-321-A
$36.25 MSRP: $58.00
You Save: $21.75 (38%)
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Product Specifications
- Replaced by: 8B3-121-321
Fits the following Audi Models:
- e-tron Quattro | 2021-2023, 2019 | Chronos Edition, Premium, Premium Plus, Prestige | BATTERY EV (EV/BEV)
- e-tron Sportback | 2020-2023 | Premium, Premium Plus, Prestige | BATTERY EV (EV/BEV)
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Audi Expansion Tank Part Number: 443-121-321
$57.46 MSRP: $79.15
You Save: $21.69 (28%)
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Product Specifications
- Other Name: Cover; Expansion Tank, Reservoir Cap
Fits the following Audi Models:
- 100 | 1989-1994 | Base, CS, E, S | 5 Cyl 2.3 L GAS, 6 Cyl 2.8 L GAS
- 100 Quattro | 1989-1994 | Base, CS | 5 Cyl 2.3 L GAS, 6 Cyl 2.8 L GAS
- 200 | 1989-1991 | Base | 5 Cyl 2.2 L GAS
- 200 Quattro | 1989-1991 | 20v, 20v Avant, Avant, Base | 5 Cyl 2.2 L GAS
- 5000 | 1984-1988 | CS, CS Turbo, S, S Turbo | 5 Cyl 2.2 L GAS, 5 Cyl 2.3 L GAS
- 5000 Quattro | 1986-1988 | CS, S | 5 Cyl 2.2 L GAS, 5 Cyl 2.3 L GAS
- 80 | 1988-1992 | Base | 4 Cyl 2.0 L GAS, 5 Cyl 2.3 L GAS
- 80 Quattro | 1988-1992 | Base | 5 Cyl 2.3 L GAS
- 90 | 1993-1995, 1988-1991 | Base, CS, S, Sport | 4 Cyl 2.0 L GAS, 5 Cyl 2.3 L GAS, 6 Cyl 2.8 L GAS
- 90 Quattro | 1993-1995, 1988-1991 | 20v, Base, CS, Sport | 5 Cyl 2.3 L GAS, 6 Cyl 2.8 L GAS
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Audi Reservoir Cap Part Number: 2Q0-121-321-A
$26.86 MSRP: $42.98
You Save: $16.12 (38%)
Ships in 1-2 Business Days
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Product Specifications
- Other Name: Cover; Cap, Reservoir Cap
- Replaces: 2Q0-121-321, 3C0-121-321
Fits the following Audi Models:
- A3 | 2022-2024, 2017-2020 | Premium, Premium Plus, Prestige, Titanium | 4 Cyl 2.0 L GAS
- A3 Quattro | 2022-2023, 2015-2020 | Premium, Premium Plus, Prestige | 4 Cyl 2.0 L GAS
- A3 Sportback e-tron | 2017-2018 | Premium, Premium Plus, Prestige | 4 Cyl 1.4 L PLUG-IN HYBRID EV-GAS (PHEV)
- A7 Sportback | 2021-2022 | Premium Plus, Prestige | 4 Cyl 2.0 L PLUG-IN HYBRID EV-GAS (PHEV)
- A8 Quattro | 2020-2021 | L Plug-In Hybrid | 6 Cyl 3.0 L PLUG-IN HYBRID EV-GAS (PHEV)
- Q3 | 2018-2024 | Premium, Premium Plus, Prestige, S-Line Premium, S-Line Premium Plus, S-Line Prestige | 4 Cyl 2.0 L GAS
- Q3 Quattro | 2018 | Premium, Premium Plus | 4 Cyl 2.0 L GAS
- Q4 e-tron | 2022-2024 | Premium, Premium Plus, Prestige | BATTERY EV (EV/BEV)
- Q4 e-tron Sportback | 2022-2024 | Premium, Premium Plus, Prestige | BATTERY EV (EV/BEV)
- Q5 | 2021-2023 | Premium, Premium Plus, Prestige | 4 Cyl 2.0 L MILD HYBRID EV-GAS (MHEV)
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Audi Radiator Cap

The Audi Radiator Cap ensures coolant is maintained at exact pressure to prolong the life of the engine and provide drivers with confidence on each journey. Audi has made its name on a combination of German engineering and day-to-day usability, from the early days in Zwickau to modern e-tron electric innovations. The brand made full-time Quattro all-wheel drive that grips wet roads and snowy passes popular, along with lightweight aluminum frames and sharp Virtual Cockpit displays that make every ride feel responsive and high-tech. Audi vehicles are also pursuing self-driving trials and introducing matrix headlights that make night driving a calmer experience, proving the company cares about progress that benefits real motorists. Just like these flagship systems, the Radiator Cap is the guardian of the heart of every powertrain. This small but important device is a reflection of Audi's commitment to durability. Mounted on the upper neck of the cooling system, the Radiator Cap seals at about 16 PSI, raising the boiling point of coolant so that heat generated by spirited acceleration cannot cause dangerous steam pockets. When the pressure gets too high, the spring valve will vent excess fluid into the reservoir, then draw it back down as the temperatures drop, keeping the circuit topped up without wasting a drop. Built with corrosion-resistant materials, each Audi Radiator Cap fits standard threads across the lineup to offer a light check and replace routine to support reliable daily commutes and weekend adventures alike.

Stick with genuine OEM Radiator Cap when you need quality that holds up. Audi crafts these parts to hit strict factory specs for every single unit. They also run each part through rigorous checks during production to maintain high quality. You can find exact Audi Radiator Cap you need in our huge stock at AudiPartsGiant.com. You'll love our low, economical prices too. Every OEM part carries a real manufacturer's warranty, so you can buy with confidence. Returns aren't a headache here because our policy is simple. Plus, our speedy delivery gets orders out fast. Shop today and buy with total peace of mind.