United States
Product overview
Genuine OEM Audi Coolant Reservoir Cap, part number 4B3121321. This cap is designed to seal the coolant expansion tank, maintaining the correct pressure within the cooling system and preventing coolant loss. It is a blue, round cap with a coolant symbol. Using a genuine OEM cap ensures proper pressure regulation and a leak-free seal, critical for efficient engine cooling and preventing overheating.
Technical details
- Category
- Engine Cooling
- Country of origin
- Germany
- Customs (HS) code
- 87089997
- Manufacturer
- Audi
- Product Type
- Genuine new auto parts
- Shipping size (L × W × H)
- 8 × 8 × 3.9 cm
- Shipping weight
- 0.07 kg
Why buy from WW Spares?
- ✓ Genuine OEM inventory sourced directly from factory networks
- ✓ Fitment support from workshop-seasoned parts specialists
- ✓ Global logistics with customs-ready documentation
Need help confirming compatibility? Talk to a specialist
Parts diagram & fitment
6 vehiclesEnd Cap — locate 4B3121321 Audi Coolant Reservoir Cap | Genuine OEM in the official exploded view and explore the surrounding assembly.
Parts in this assembly20
- 1Radiator 8K0121251AB
- 1Radiator 8K0121251AM
- 2Part WHT001506A
- 3Rubber Bush 8K0121275C
- 4Rubber Bush 8K0121276A
- 5Support 8K0805201
- 6Bolt N90967502
- 7Rubber Bush 8K0121268C
- 8Screw N10442003
- 10Container 8T0121405
- 11Adapter 8K0133426A
- 12Bolt N91073301
- 13Retainer 8T0121409
- 14Part N90488005
- 16Part N90570802
- 20Coolant GA13A8JM8
- 20Coolant GA13A8JM9
- 20Coolant GA13040M2
- 20Coolant GA13774M2
- 20Coolant GA13A8JM1
Compatible / alternative parts(2)
Vehicle fitment table6
Europe (6)
| Vehicle | Years | Pos. | Qty | Remark | PR |
|---|---|---|---|---|---|
| Audi RS4 Av. qu. 4.2 | 2012-2015 | 15 | 1 | TN8 | |
| Audi R8 qu. 5.2 | 2012-2015 | 23 | 1 | PR:K8W | |
| Audi RS5 Cabrio | 2012-2015 | 15 | 1 | TN8 | |
| Audi RS5 Coupe | 2010-2015 | 15 | 1 | TN8 | |
| Audi R8 08> | 2007- | 23 | 1 | PR:K8U,K8W | K8U |
| Audi RS6 Avant qu.5.0 | 2007-2010 | 19 | 1 | TT7 |
Diagrams & fitment data powered by oemdiagrams.com
4B3121321 Audi Coolant Reservoir Cap | Genuine OEM is fitted on: Audi RS4 Av. qu. 4.2 2012-2015; Audi R8 qu. 5.2 2012-2015; Audi RS5 Cabrio 2012-2015; Audi RS5 Coupe 2010-2015; Audi R8 08> 2007-; Audi RS6 Avant qu.5.0 2007-2010.
