The 5Q0 122 291BL is the genuine OE upper radiator coolant hose adapter engineered specifically for 2.0T EA888 Evo4 high-performance MQB-platform vehicles from Volkswagen and Audi — including the Golf R, Arteon, Golf VIII R, S3, and TTS Quattro. Mounted in the upper cooling circuit, this 4-port connector serves as the sealed junction between the upper coolant hose and the radiator assembly under full system pressure. This part is engine-code specific to Evo4 variants (CYFB, DJJA, DLRA, CJXB/CJXF) and does not interchange with standard 2.0T applications. Always confirm fitment by VIN before ordering.
$35.10
The 5Q0 122 291BL Coolant Connector is a Genuine OE 4-port upper radiator hose adapter. It mounts at the upper hose-to-radiator junction in the EA888 Evo4 MQB cooling circuit. Specifically, it manages coolant distribution between the upper hose, radiator, and secondary circuit branches simultaneously. As a result, coolant routes correctly across all four ports under the elevated thermal and pressure conditions of Evo4 power outputs. Furthermore, VAG engineers developed this fitting exclusively for Evo4 variants. Those variants carry engine codes CYFB, DJJA, DLRA, and CJXB/CJXF. Therefore, the 5Q0 122 291BL is not interchangeable with standard EA888 2.0T upper hose connectors used elsewhere in the MQB lineup. Consequently, confirming the engine code by VIN before ordering is essential.
The 5Q0 122 291BL operates under sustained thermal and mechanical stress. Specifically, elevated system pressure, repeated heat cycling, and engine vibration all act on the plastic body continuously. As a result, the material becomes brittle over time. Hairline cracks then initiate most often at the upper hose coupling port and the radiator inlet connection point. Those locations bear the greatest concentration of thermal stress. Even a minor crack at either point allows coolant to bypass the sealing surface. Consequently, gradual coolant loss begins. Moreover, persistent low-coolant warnings follow. In performance driving conditions, furthermore, the overheating risk escalates faster than in standard applications. Therefore, replacing the 5Q0 122 291BL promptly restores factory-correct port geometry, coupling retention, and sealing surface integrity.
OEM Reference: 5Q0 122 291BL
Genuine OE 4-port upper radiator coolant hose adapter for EA888 Evo4 applications
Engine-code specific: CYFB, DJJA, DLRA, CJXB/CJXF — high-performance Evo4 variants only
Upper hose-to-radiator position; precision-engineered port geometry for correct hose seating across all four connections
OE construction rated for continuous elevated coolant temperatures and Evo4 system pressure
Compatible with VW/Audi factory G12++/G13 coolant chemistry
Direct-fit replacement — no modifications required
Catching a failing 5Q0 122 291BL early is especially critical in high-performance applications. Therefore, watch for these warning signs:
Coolant seeping, staining, or leaving dried residue at any of the four connector ports or along the upper hose junction
Recurring low coolant warnings despite topping off the reservoir, with no other visible external leak source
Sweet coolant odor from the engine bay after the engine reaches normal operating temperature
Visible surface cracking, crazing, or discoloration on the plastic connector body — especially at the upper hose coupling port
Any coolant hose at the connector that does not seat firmly or feels loose after engaging the quick-release coupling
If any of these symptoms appear, replace the connector promptly. Additionally, pressure-test the cooling system before returning the vehicle to service.
Always verify fitment by VIN before ordering. Multiple variants may exist within the same model year.
5Q0 122 291BL (VAG OEM — upper radiator coolant hose adapter, 4-port, EA888 Evo4)
| Weight | 0.25 lbs |
|---|---|
| Dimensions | 6.0 × 4.0 × 3.0 in |
| Year | Make | Model | Engine | Notes |
|---|---|---|---|---|
| 2015-2020 | Audi | S3 | 2.0L | |
| 2016-2018 | Audi | TTS | 2.0L | |
| 2018-2019 | Volkswagen | Golf R | 2.0L |
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