Genuine 4G0 121 081AE Engine Coolant Overflow Hose

The Genuine 4G0121081AE is an OEM engine coolant overflow hose designed to feed coolant back to the overflow or recovery bottle in a closed-loop cooling system. This is an expansion tank upper hose positioned on the left side, serving as a critical component in maintaining proper engine temperature and cooling system pressure.

Key Features:

• Handles radiator overflow and keeps coolant in the system by flowing coolant back to the coolant expansion tank
• Constructed from high temperature-resistant rubber or silicone material that withstands extreme engine operating conditions and corrosion
• Features flexibility to adapt to engine vibration and movement during operation
• Engineered with pressure resistance to prevent leakage under cooling system pressure
• Genuine Volkswagen Audi OEM quality for precise fit and reliability

This coolant reservoir hose allows coolant to enter the engine cooling system from the tank and flow back, helping maintain a constant cooling system level as coolant expands or contracts due to temperature changes, preventing engine overheating. Also known by superseded part number 4G0-121-081-AE, and replaces part numbers 4G0121081EJ and 4G0121081CT.