Genuine 4M0 121 081 DD Coolant Expansion Tank Breather Hose Upper

The Genuine 4M0 121 081 DD is an OEM upper coolant expansion tank breather hose (also referred to as a vent hose or coolant pipe) sourced directly from the Volkswagen Audi Group. This hose connects on the upper side of the coolant expansion tank, near the reservoir cap, and serves as the critical venting link between the expansion tank and the rest of the cooling circuit.

The coolant expansion tank breather hose allows air and pressure to move safely within the cooling system as coolant heats up and expands during engine operation. A cracked, hardened, or leaking vent hose can result in coolant loss, improper pressurization, and potential overheating. Replacing this hose with a genuine OEM part ensures a precise fit and restores proper cooling system function.

Key Features:

• Genuine OEM part — manufactured to original Volkswagen Audi Group specifications
• Upper expansion tank connection point, positioned near the reservoir cap
• Maintains proper coolant system pressure and venting
• Exact replacement for a direct, hassle-free installation
• Part of the Volkswagen Group parts network, also cross-referenced for Porsche, Bentley, and Lamborghini platforms

Replace a cracked or deteriorated coolant breather hose promptly to protect your engine's cooling system. Using a genuine OEM hose guarantees the correct dimensions, material durability, and fit for a factory-quality repair.

OEM Part Number: 4M0 121 081 DD | 4M0121081DD