Audi / Porsche Coolant Reservoir / Tank / Bottle Cap 4M0121321Q

OEM Part #: 4M0-121-321-Q (4M0121321Q)

Porsche Part #: PAB121321B

This page covers one exact OEM part number. Every unit we stocked has sold.

The OEM Coolant Reservoir Tank Cap (Part Number: 4M0121321Q) is crucial for maintaining optimal pressure within the coolant system of select Audi and Porsche models. Located atop the coolant reservoir, this cap ensures that the coolant remains contained and at proper levels, which is essential for effective engine cooling. It interfaces directly with the expansion tank, allowing for thermal expansion of the coolant during engine operation. Common issues requiring replacement include cracks or leaks in the cap, which can lead to coolant loss and engine overheating. This cap is compatible with various Audi models, including the Q5, Q7, and RS5, across model years 2016 to 2024, as well as the Porsche Cayenne from 2018 to 2024. Alternative terms include reservoir cap and radiator cap.

Specifications

Specifications for Coolant Reservoir / Tank / Bottle Cap 4M0121321Q
Fits Vehicle ModelA4, A5, A6, A8, Cayenne, Q5, Q5 PHEV, Q7, Q8, RS Q8, RS5, S4, S5, S6, S8, SQ5
Fits Vehicle MakeAudi, Porsche
OEM Part No4M0-121-321-Q (4M0121321Q)
Porsche Part NoPAB121321B
Compatible OEM Part No PAB12132100, 4M0-121-321-J, 4M0-121-321-K, 4M0-121-321-E, 4M0-121-321-H
CategoryRadiator / Coolant

Compatible Vehicles

Fits 183 vehicle configurations across 2 makes, 2017-2024.

Check your specific vehicle before ordering. This list shows year, make, and model. Some years have multiple trims or engines that use different parts, and individual listings may have additional fitment notes (e.g. “with sunroof only”). Review the full variant list below, or message us with your VIN and we’ll confirm the match.

Audi

  • A4 2017-2024 · 12 variants 6 with notes
  • A5 2017-2024 · 23 variants 15 with notes
  • A6 2020-2024 · 10 variants 10 with notes
  • A8 2020-2024 · 7 variants 7 with notes
  • Q5 2020-2024 · 5 variants 5 with notes
  • Q5 PHEV 2020-2024 · 5 variants 5 with notes
  • Q7 2017-2024 · 14 variants 12 with notes
  • Q8 2019-2024 · 6 variants 5 with notes
  • RS Q8 2020-2024 · 5 variants 5 with notes
  • RS5 2021-2024 · 8 variants 8 with notes
  • S4 2020-2024 · 5 variants 5 with notes
  • S5 2020-2024 · 15 variants 15 with notes
  • S6 2020-2024 · 5 variants 5 with notes
  • S8 2020-2024 · 5 variants 5 with notes
  • SQ5 2020-2024 · 5 variants 5 with notes

Porsche

View all 183 vehicle configurations 113 with fitment notes
Full vehicle fitment list for Coolant Reservoir / Tank / Bottle Cap 4M0121321Q
Year Make Model Trim Engine Note
2017 Audi A4 Sedan 2.0L l4 Turbo
2017 Audi A4 Quattro Sedan 2.0L l4 Turbo
2017 Audi A5 Quattro Convertible 2.0L l4 Turbo
2017 Audi A5 Quattro Coupe 2.0L l4 Turbo
2017 Audi Q7 SUV 2.0L l4 Turbo
2018 Audi A4 Sedan 2.0L l4 Turbo
2018 Audi A4 Quattro Sedan 2.0L l4 Turbo
2018 Audi A5 Quattro Convertible 2.0L l4 Turbo
2018 Audi A5 Quattro Coupe 2.0L l4 Turbo
2018 Audi A5 Hatchback 2.0L l4 Turbo
2018 Audi Q7 SUV 2.0L l4 Turbo
2019 Audi A4 Sedan 2.0L l4 Turbo
2019 Audi A4 Quattro Sedan 2.0L l4 Turbo
2019 Audi A5 Quattro Convertible 2.0L l4 Turbo
2019 Audi A5 Quattro Coupe 2.0L l4 Turbo
2019 Audi A5 Hatchback 2.0L l4 Turbo
2019 Audi Q7 SUV 2.0L l4 Turbo For Vehicles with Production Date After 11/04/19
2019 Audi Q7 SUV 3.0L V6 Supercharged For Vehicles with Production Date After 11/04/19
2020 Audi A4 Sedan 2.0L l4 Turbo For Vehicles with Production Date After 06/15/20
2020 Audi A4 Quattro Sedan 2.0L l4 Turbo For Vehicles with Production Date After 06/15/20
2020 Audi A5 Quattro Convertible 2.0L l4 Turbo For Vehicles with Production Date After 06/15/20
2020 Audi A5 Quattro Coupe 2.0L l4 Turbo For Vehicles with Production Date After 06/15/20
2020 Audi A5 Hatchback 2.0L l4 Turbo For Vehicles with Production Date After 06/15/20
2020 Audi A6 Quattro Sedan 2.0L l4 Turbo For Vehicles with Production Date After 07/06/20
2020 Audi Q5 SUV 2.0L l4 Turbo For Vehicles with Production Date Between 06/22/20 and 08/17/20
2020 Audi Q7 SUV 2.0L l4 Turbo For Vehicles with Production Date After 08/24/20
2020 Audi S4 Sedan 3.0L V6 Turbo For Vehicles with Production Date After 06/15/20
2020 Audi S5 Convertible 3.0L V6 Turbo For Vehicles with Production Date After 05/25/20
2020 Audi S5 Coupe 3.0L V6 Turbo For Vehicles with Production Date After 06/15/20
2020 Audi S5 Hatchback 3.0L V6 Turbo For Vehicles with Production Date After 06/15/20
2020 Audi SQ5 SUV 3.0L V6 Turbo For Vehicles with Production Date After 06/22/20
2021 Audi Q7 SUV 2.0L l4 Turbo For Vehicles with Production Date After 08/24/20
2021 Audi RS5 Coupe 2.9L V6 Turbo For Vehicles with Production Date After 06/15/20
2021 Audi RS5 Hatchback 2.9L V6 Turbo For Vehicles with Production Date After 06/15/20
2021 Audi S4 Sedan 3.0L V6 Turbo For Vehicles with Production Date After 06/15/20
2021 Audi S5 Convertible 3.0L V6 Turbo For Vehicles with Production Date After 05/25/20
2021 Audi S5 Coupe 3.0L V6 Turbo For Vehicles with Production Date After 06/15/20
2021 Audi S5 Hatchback 3.0L V6 Turbo For Vehicles with Production Date After 06/15/20
2021 Audi SQ5 SUV 3.0L V6 Turbo For Vehicles with Production Date After 06/22/20
2022 Audi Q7 SUV 2.0L l4 Turbo For Vehicles with Production Date After 08/24/20
2022 Audi RS5 Coupe 2.9L V6 Turbo For Vehicles with Production Date After 06/15/20
2022 Audi RS5 Hatchback 2.9L V6 Turbo For Vehicles with Production Date After 06/15/20
2022 Audi S4 Sedan 3.0L V6 Turbo For Vehicles with Production Date After 06/15/20
2022 Audi S5 Convertible 3.0L V6 Turbo For Vehicles with Production Date After 05/25/20
2022 Audi S5 Coupe 3.0L V6 Turbo For Vehicles with Production Date After 06/15/20
2022 Audi S5 Hatchback 3.0L V6 Turbo For Vehicles with Production Date After 06/15/20
2022 Audi SQ5 SUV 3.0L V6 Turbo For Vehicles with Production Date After 06/22/20
2019 Porsche Cayenne SUV 3.0L V6 Turbo
2019 Porsche Cayenne S SUV 2.9L V6 Turbo
2019 Porsche Cayenne Turbo SUV 4.0L V8 Turbo
2020 Porsche Cayenne SUV 3.0L V6 Turbo
2020 Porsche Cayenne Coupe SUV 3.0L V6 Turbo
2020 Porsche Cayenne S Coupe SUV 2.9L V6 Turbo
2020 Porsche Cayenne S SUV 2.9L V6 Turbo
2020 Porsche Cayenne Turbo Coupe SUV 4.0L V8 Turbo
2020 Porsche Cayenne Turbo SUV 4.0L V8 Turbo
2021 Porsche Cayenne SUV 3.0L V6 Turbo
2021 Porsche Cayenne Coupe SUV 3.0L V6 Turbo
2021 Porsche Cayenne GTS Coupe SUV 4.0L V8 Turbo
2021 Porsche Cayenne GTS SUV 4.0L V8 Turbo
2021 Porsche Cayenne S Coupe SUV 2.9L V6 Turbo
2021 Porsche Cayenne S SUV 2.9L V6 Turbo
2021 Porsche Cayenne Turbo Coupe SUV 4.0L V8 Turbo
2021 Porsche Cayenne Turbo SUV 4.0L V8 Turbo
2022 Porsche Cayenne SUV 3.0L V6 Turbo
2022 Porsche Cayenne Coupe SUV 3.0L V6 Turbo
2022 Porsche Cayenne GTS SUV 4.0L V8 Turbo
2022 Porsche Cayenne S Coupe SUV 2.9L V6 Turbo
2022 Porsche Cayenne S SUV 2.9L V6 Turbo
2022 Porsche Cayenne Turbo Coupe SUV 4.0L V8 Turbo
2022 Porsche Cayenne Turbo GT Coupe SUV 4.0L V8 Turbo
2022 Porsche Cayenne Turbo SUV 4.0L V8 Turbo
2019 Audi Q8 SUV 3.0L V6 Turbo
2020 Audi A6 Quattro Sedan 3.0L V6 Turbo For Vehicles with Production Date After 09/07/20
2020 Audi A8 Quattro L Sedan 3.0L V6 Turbo For Vehicles with Production Date After 06/08/20
2020 Audi A8 Quattro L Sedan 4.0L V8 Turbo For Vehicles with Production Date After 06/08/20
2020 Audi Q5 PHEV SUV 2.0L l4 Turbo For Vehicles with Production Date Between 06/22/20 and 08/17/20
2020 Audi Q7 SUV 3.0L V6 Turbo For Vehicles with Production Date After 08/24/20
2020 Audi Q8 SUV 3.0L V6 Turbo For Vehicles with Production Date After 08/24/20
2020 Audi RS Q8 SUV 4.0L V8 Turbo For Vehicles with Production Date After 08/24/20
2020 Audi S6 Sedan 2.9L V6 Turbo For Vehicles with Production Date After 09/07/20
2020 Audi S8 Sedan 4.0L V8 Turbo For Vehicles with Production Date After 06/08/20
2021 Audi A4 Quattro Sedan 2.0L l4 Turbo For Vehicles with Production Date After 06/15/20
2021 Audi A5 Quattro Convertible 2.0L l4 Turbo For Vehicles with Production Date After 06/15/20
2021 Audi A5 Quattro Coupe 2.0L l4 Turbo For Vehicles with Production Date After 06/15/20
2021 Audi A5 Hatchback 2.0L l4 Turbo For Vehicles with Production Date After 06/15/20
2021 Audi A6 Quattro Sedan 2.0L l4 Turbo For Vehicles with Production Date After 07/06/20
2021 Audi A6 Quattro Sedan 3.0L V6 Turbo For Vehicles with Production Date After 09/07/20
2021 Audi A8 Quattro L Sedan 3.0L V6 Turbo For Vehicles with Production Date After 06/08/20
2021 Audi A8 Quattro L Sedan 4.0L V8 Turbo For Vehicles with Production Date After 06/08/20
2021 Audi Q5 SUV 2.0L l4 Turbo For Vehicles with Production Date Between 06/22/20 and 08/17/20
2021 Audi Q5 PHEV SUV 2.0L l4 Turbo For Vehicles with Production Date Between 06/22/20 and 08/17/20
2021 Audi Q7 SUV 3.0L V6 Turbo For Vehicles with Production Date After 08/24/20
2021 Audi Q8 SUV 3.0L V6 Turbo For Vehicles with Production Date After 08/24/20
2021 Audi RS Q8 SUV 4.0L V8 Turbo For Vehicles with Production Date After 08/24/20
2021 Audi S6 Sedan 2.9L V6 Turbo For Vehicles with Production Date After 09/07/20
2021 Audi S8 Sedan 4.0L V8 Turbo For Vehicles with Production Date After 06/08/20
2022 Audi A4 Quattro Sedan 2.0L l4 Turbo For Vehicles with Production Date After 06/15/20
2022 Audi A5 Quattro Convertible 2.0L l4 Turbo For Vehicles with Production Date After 06/15/20
2022 Audi A5 Quattro Coupe 2.0L l4 Turbo For Vehicles with Production Date After 06/15/20
2022 Audi A5 Hatchback 2.0L l4 Turbo For Vehicles with Production Date After 06/15/20
2022 Audi A6 Quattro Sedan 2.0L l4 Turbo For Vehicles with Production Date After 07/06/20
2022 Audi A6 Quattro Sedan 3.0L V6 Turbo For Vehicles with Production Date After 09/07/20
2022 Audi A8 Quattro L Sedan 3.0L V6 Turbo For Vehicles with Production Date After 06/08/20
2022 Audi Q5 SUV 2.0L l4 Turbo For Vehicles with Production Date After 06/22/20
2022 Audi Q5 PHEV SUV 2.0L l4 Turbo For Vehicles with Production Date After 06/22/20
2022 Audi Q7 SUV 3.0L V6 Turbo For Vehicles with Production Date After 08/24/20
2022 Audi Q8 SUV 3.0L V6 Turbo For Vehicles with Production Date After 08/24/20
2022 Audi RS Q8 SUV 4.0L V8 Turbo For Vehicles with Production Date After 08/24/20
2022 Audi S6 Sedan 2.9L V6 Turbo For Vehicles with Production Date After 09/07/20
2022 Audi S8 Sedan 4.0L V8 Turbo For Vehicles with Production Date After 06/08/20
2023 Audi A4 Quattro Sedan 2.0L l4 Turbo For Vehicles with Production Date After 06/15/20
2023 Audi A5 Quattro Convertible 2.0L l4 Turbo For Vehicles with Production Date After 06/15/20
2023 Audi A5 Quattro Coupe 2.0L l4 Turbo For Vehicles with Production Date After 06/15/20
2023 Audi A5 Hatchback 2.0L l4 Turbo For Vehicles with Production Date After 06/15/20
2023 Audi A6 Quattro Sedan 2.0L l4 Turbo For Vehicles with Production Date After 07/06/20
2023 Audi A6 Quattro Sedan 3.0L V6 Turbo For Vehicles with Production Date After 09/07/20
2023 Audi A8 Quattro L Sedan 3.0L V6 Turbo For Vehicles with Production Date After 06/08/20
2023 Audi Q5 SUV 2.0L l4 Turbo For Vehicles with Production Date After 06/22/20
2023 Audi Q5 PHEV SUV 2.0L l4 Turbo For Vehicles with Production Date After 06/22/20
2023 Audi Q7 SUV 2.0L l4 Turbo For Vehicles with Production Date After 08/24/20
2023 Audi Q7 SUV 3.0L V6 Turbo For Vehicles with Production Date After 08/24/20
2023 Audi Q8 SUV 3.0L V6 Turbo For Vehicles with Production Date After 08/24/20
2023 Audi RS5 Coupe 2.9L V6 Turbo For Vehicles with Production Date After 06/15/20
2023 Audi RS5 Hatchback 2.9L V6 Turbo For Vehicles with Production Date After 06/15/20
2023 Audi RS Q8 SUV 4.0L V8 Turbo For Vehicles with Production Date After 08/24/20
2023 Audi S4 Sedan 3.0L V6 Turbo For Vehicles with Production Date After 06/15/20
2023 Audi S5 Convertible 3.0L V6 Turbo For Vehicles with Production Date After 05/25/20
2023 Audi S5 Coupe 3.0L V6 Turbo For Vehicles with Production Date After 06/15/20
2023 Audi S5 Hatchback 3.0L V6 Turbo For Vehicles with Production Date After 06/15/20
2023 Audi S6 Sedan 2.9L V6 Turbo For Vehicles with Production Date After 09/07/20
2023 Audi S8 Sedan 4.0L V8 Turbo For Vehicles with Production Date After 06/08/20
2023 Audi SQ5 SUV 3.0L V6 Turbo For Vehicles with Production Date After 06/22/20
2018 Porsche Cayenne S SUV 3.0L V6 Supercharged
2020 Porsche Cayenne Turbo S Coupe SUV 4.0L V8 Turbo
2020 Porsche Cayenne Turbo S SUV 4.0L V8 Turbo
2021 Porsche Cayenne Turbo S Coupe SUV 4.0L V8 Turbo
2021 Porsche Cayenne Turbo S SUV 4.0L V8 Turbo
2022 Porsche Cayenne GTS Coupe SUV 4.0L V8 Turbo
2022 Porsche Cayenne Turbo S Coupe SUV 4.0L V8 Turbo
2022 Porsche Cayenne Turbo S SUV 4.0L V8 Turbo
2023 Porsche Cayenne SUV 3.0L V6 Turbo
2023 Porsche Cayenne Coupe SUV 3.0L V6 Turbo
2023 Porsche Cayenne GTS Coupe SUV 4.0L V8 Turbo
2023 Porsche Cayenne GTS SUV 4.0L V8 Turbo
2023 Porsche Cayenne S Coupe SUV 2.9L V6 Turbo
2023 Porsche Cayenne S SUV 2.9L V6 Turbo
2023 Porsche Cayenne Turbo Coupe SUV 4.0L V8 Turbo
2023 Porsche Cayenne Turbo GT Coupe SUV 4.0L V8 Turbo
2023 Porsche Cayenne Turbo S Coupe SUV 4.0L V8 Turbo
2023 Porsche Cayenne Turbo S SUV 4.0L V8 Turbo
2023 Porsche Cayenne Turbo SUV 4.0L V8 Turbo
2024 Audi A4 Quattro Sedan 2.0L l4 Turbo For Vehicles with Production Date After 06/15/20
2024 Audi A5 Quattro Convertible 2.0L l4 Turbo For Vehicles with Production Date After 06/15/20
2024 Audi A5 Quattro Coupe 2.0L l4 Turbo For Vehicles with Production Date After 06/15/20
2024 Audi A5 Hatchback 2.0L l4 Turbo For Vehicles with Production Date After 06/15/20
2024 Audi A6 Quattro Sedan 2.0L l4 Turbo For Vehicles with Production Date After 07/06/20
2024 Audi A6 Quattro Sedan 3.0L V6 Turbo For Vehicles with Production Date After 09/07/20
2024 Audi A8 Quattro L Sedan 3.0L V6 Turbo For Vehicles with Production Date After 06/08/20
2024 Audi Q5 SUV 2.0L l4 Turbo For Vehicles with Production Date After 06/22/20
2024 Audi Q5 PHEV SUV 2.0L l4 Turbo For Vehicles with Production Date After 06/22/20
2024 Audi Q7 SUV 2.0L l4 Turbo For Vehicles with Production Date After 08/24/20
2024 Audi Q7 SUV 3.0L V6 Turbo For Vehicles with Production Date After 08/24/20
2024 Audi Q8 SUV 3.0L V6 Turbo For Vehicles with Production Date After 08/24/20
2024 Audi RS5 Coupe 2.9L V6 Turbo For Vehicles with Production Date After 06/15/20
2024 Audi RS5 Hatchback 2.9L V6 Turbo For Vehicles with Production Date After 06/15/20
2024 Audi RS Q8 SUV 4.0L V8 Turbo For Vehicles with Production Date After 08/24/20
2024 Audi S4 Sedan 3.0L V6 Turbo For Vehicles with Production Date After 06/15/20
2024 Audi S5 Convertible 3.0L V6 Turbo For Vehicles with Production Date After 05/25/20
2024 Audi S5 Coupe 3.0L V6 Turbo For Vehicles with Production Date After 06/15/20
2024 Audi S5 Hatchback 3.0L V6 Turbo For Vehicles with Production Date After 06/15/20
2024 Audi S6 Sedan 2.9L V6 Turbo For Vehicles with Production Date After 09/07/20
2024 Audi S8 Sedan 4.0L V8 Turbo For Vehicles with Production Date After 06/08/20
2024 Audi SQ5 SUV 3.0L V6 Turbo For Vehicles with Production Date After 06/22/20
2024 Porsche Cayenne SUV 3.0L V6 Turbo
2024 Porsche Cayenne Coupe SUV 3.0L V6 Turbo
2024 Porsche Cayenne S Coupe SUV 4.0L V8 Turbo
2024 Porsche Cayenne S Coupe SUV 3.0L V6 Turbo
2024 Porsche Cayenne S SUV 3.0L V6 Turbo
2024 Porsche Cayenne S SUV 4.0L V8 Turbo
2024 Porsche Cayenne Turbo Coupe SUV 4.0L V8 Turbo
2024 Porsche Cayenne Turbo SUV 4.0L V8 Turbo
2024 Porsche Cayenne Turbo GT Coupe SUV 4.0L V8 Turbo

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