The 5Q0 122 291CT is the OE upper radiator coolant hose adapter, positioned at the water pump housing on select Volkswagen and Audi MQB-platform vehicles. Designed for the VW Golf R (2015–2019) and Audi A3/S3/TT/TTS 2.0T models, this connector provides the sealed junction between the upper coolant hose and the water pump outlet. The part ships with an integrated C-clip and seal and is a single-use component — always install with new sealing hardware included in the kit. Supersedes 5Q0 122 291BF.
$37.80
3 in stock
The 5Q0 122 291CT Coolant Connector is the OE upper radiator hose adapter used at the water pump housing on select Volkswagen and Audi MQB-platform vehicles. Mounted at the water pump outlet, this fitting creates the primary sealed junction where the upper radiator hose connects to the engine’s cooling circuit, channeling coolant from the engine to the radiator under full system pressure and temperature. Because it sits directly at the water pump housing — the highest-flow point in the upper circuit — it faces continuous coolant pressure, elevated operating temperatures, and repeated thermal cycling throughout the life of the vehicle.
Over time, the original plastic connector weakens from heat exposure and pressure fatigue. Hairline cracks form at the sealing surface and hose barb, where stress concentrates most. Even a small crack allows coolant to seep past the C-clip seal, triggering low-coolant warnings and, if left unaddressed, progressing to significant coolant loss and potential overheating. Replacing the failing connector with a new 5Q0 122 291CT restores a factory-correct, pressure-tight seal at the water pump housing and returns the cooling system to full reliable operation.
Catching a failing upper coolant hose connector early prevents heat damage and protects against unexpected coolant loss. Watch for these warning signs:
Coolant seeping, staining, or drying around the upper hose connection at the water pump housing
Persistent low coolant warnings requiring repeated top-ups with no obvious external leak elsewhere
Sweet coolant odor from the engine bay after the engine reaches operating temperature
Visible cracking, crazing, or surface discoloration on the connector body
Upper radiator hose that feels loose or fails to click and lock securely at the connector
If any of these indicators appear, replace the 5Q0 122 291CT coolant connector promptly and pressure-test the cooling system before returning the vehicle to service.
OEM Reference: 5Q0 122 291CT (supersedes 5Q0 122 291BF)
OE upper radiator hose adapter positioned at the water pump housing
Includes C-clip and seal — complete, ready-to-install hardware
Single-use component — must be replaced, not reinstalled after removal
Precision-molded housing engineered to OE geometry for correct hose seating and pressure-tight retention
Compatible with factory-style G12++/G13 coolant chemistry
Direct-fit replacement — no modifications required
This is a single-use part — always install a new connector; never reuse the removed unit
First, use the included C-clip and seal supplied with the part — do not reuse hardware from the old connector
Next, inspect the upper radiator hose for softness, swelling, or surface cracking; replacing both at the same service interval is best practice
Also, verify the C-clip seats fully and the hose clicks securely into the connector before pressurizing the system
Finally, refill with the correct VW/Audi-approved coolant (G12++/G13 per your owner’s manual) and bleed the cooling system completely to eliminate air pockets before returning the vehicle to service
Always verify fitment by VIN before ordering. Multiple variants may exist within the same model year.
5Q0 122 291CT (VAG OEM — current)
5Q0 122 291BF (VAG OEM — superseded)
| Weight | 0.25 lbs |
|---|---|
| Dimensions | 6.0 × 4.0 × 3.0 in |
| Year | Make | Model | Engine | Notes |
|---|---|---|---|---|
| 2016-2018 | Audi | TTS | ||
| 2018-2019 | Volkswagen | Golf R |
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