Coolant Hose Connector (Lower Radiator Hose) – 5N0 122 291C (VIKA)

Description

The 5N0 122 291C Coolant Hose Adapter by VIKA is an OE-style lower radiator coupling piece. Specifically, it is designed for the Volkswagen Tiguan Mk1 (5N-chassis) equipped with the 2.0L four-cylinder engine. Positioned at the front lower hose-to-radiator junction, this fitting connects the lower coolant hose to the radiator outlet port, completing the return path of the primary cooling circuit. Furthermore, the 5N0 122 291C is the lower-position counterpart to the upper adapter (5N0 122 291), and both fittings serve distinct positions within the same cooling circuit. Because the 5N-chassis Tiguan uses a unique PQ46-based cooling layout, this adapter is specific to the Mk1 Tiguan (2009–2018). As a result, it does not interchange with Mk2 MQB-platform Tiguan variants.

Over time, the plastic body of the 5N0 122 291C coolant hose adapter weakens from continuous heat cycling and sustained coolant pressure. In particular, the lower coupling port — where returning coolant flows from the radiator back toward the engine — experiences frequent temperature swings between cold start and operating temperature. Consequently, the plastic body can develop hairline cracks at the port walls or coupling groove. Additionally, the sealing surface can warp or degrade, breaking the tight junction between the hose and the adapter. Even a small failure at this position allows coolant to bypass the coupling, leading to gradual coolant loss and recurring low-coolant warnings. Therefore, replacing the failing 5N0 122 291C promptly prevents the risk of progressive engine overheating.

Why Choose VIKA for the 5N0 122 291C Coolant Hose Adapter

VIKA is a European OE-style aftermarket supplier that engineers cooling components to factory connector geometry and port dimensions. As a result, the 5N0 122 291C fits the lower radiator hose junction without modification. Moreover, VIKA’s precision-molded plastic/composite construction matches the wall thickness and coupling engagement tolerances of the Genuine VW part. Consequently, the sealing performance meets OE-style standards while offering a cost-effective price alternative to the dealer component. In addition, the direct-fit design means installation requires no special tools or hose rerouting.

Signs Your Lower Coolant Hose Adapter Needs Replacing

Catching a failing 5N0 122 291C early prevents escalating cooling system damage. Therefore, watch for these warning signs:

• Coolant seeping or leaving dried residue near the lower radiator hose coupling at the front of the radiator

• Recurring low coolant level warnings despite topping off the reservoir, with no other visible leak source

• A sweet coolant odor from the lower engine bay after reaching normal operating temperature

• Visible cracking, crazing, or discoloration on the plastic coupling body or at the hose barb

• The lower radiator hose feeling loose at the coupling connection or showing signs of seeping at the joint

If any of these symptoms appear, replace the 5N0 122 291C promptly. Additionally, inspect the upper adapter (5N0 122 291) at the same time, since both fittings share the same heat and pressure exposure on the Tiguan Mk1.

5N0 122 291C Coolant Hose Adapter — Key Features

• OEM Reference: 5N0 122 291C (VIKA OE-style aftermarket)

• Lower radiator coolant hose adapter — front position

• Precision-molded plastic/composite construction to match OE connector geometry

• Engineered specifically for the lower radiator hose junction on the VW Tiguan Mk1 (5N-chassis)

• Compatible with the 2.0L EA113/EA888 engine (1984cc)

• Compatible with factory-style hose clamps and O-rings (where applicable)

• Cost-effective OE-style alternative to the Genuine VW dealer component

• Direct-fit replacement — no modifications required

Service Notes for the 5N0 122 291C Coolant Hose Adapter

• First, confirm fitment by VIN — this lower adapter fits the Tiguan Mk1 (5N) only and does not fit Mk2 MQB variants

• Next, replace any associated O-rings and hose clamps during installation; never reuse worn sealing hardware on a new coupling

• Also, inspect the upper adapter (5N0 122 291) at the same service interval; replacing both fittings together prevents a repeat cooling system visit

• Then, inspect the lower radiator hose for softness, swelling, or cracking at the coupling end before reinstalling

• Finally, refill with VW-approved G12++/G13 coolant and bleed the cooling system completely to eliminate air pockets before returning the vehicle to service

5N0 122 291C Coolant Hose Adapter — Compatibility & Applications

Always verify fitment by VIN before ordering. Multiple variants may exist within the same model year.

Cross Reference Numbers

• 5N0 122 291C (VAG OEM reference — VIKA OE-style replacement)

• 5N0-122-291-C (alternate formatting)

Additional information