Coolant Hose / Engine Cooling System Water Pipe – 4K0121071J

Original cooling system pipe (coolant circulation hose / engine compartment water main), designed for Audi A7 Sportback (4K / 4K8 generation) and Audi A6 C8 (4K2 / 4K5 / 4KA type) with a turbocharged 3.0 V6 TFSI (55 TFSI designation / EA839 family / DLZA, DKMB and related codes) engine based on the modular MLBevo longitudinal platform.

Original VAG cooling system component. Made of specialized engineering plastic with enhanced thermo-mechanical resistance, combined with reinforced elastomer fittings resistant to continuous operating pressure, the aggressive environment of coolant glycol (G12evo / G13 fluid), and high temperatures in the engine compartment. It is responsible for the precise circulation of coolant between the engine accessories and the main cooling circuit, stabilizing the thermal balance of the 3.0 V6 unit and protecting it from localized overheating.

Technical specifications:

• Catalog part number (OE): 4K0121071J / 4K0 121 071 J (interchangeable with revisions in the 4K0121071, 4K0121071A, 4K0121071E series)

• System / Category: Engine cooling system (Engine Cooling System / Coolant Water Line)

• Function: Coolant circulation hose / water pipe (Coolant Hose / Pipe)

• Dedicated engine: 3.0 V6 TFSI (55 TFSI / EA839) and related V6 gasoline engines on the MLBevo platform

• Construction: Thermally molded structural plastic with factory quick-release snap fittings (Quick-Connector) and O-ring seals

• Installation side: Engine compartment – 3.0 V6 power unit cooling accessory area

• Steering side: Left (LHD – European version) and Right (RHD) – universal component

• Condition: Original used part (100% functional, leak-tight, unobstructed, plastic in good condition, no microcracks, no signs of heat-induced material degradation, quick-connector sockets intact, locking tabs functional)

• Manufacturer: Audi AG / VAG (Original OEM)

Main application:

• Audi:

  • A7 Sportback (type 4K8) – model years 2018 to 2026 (3.0 TFSI / 55 TFSI engines)

  • S7 Sportback (type 4K8) – model years 2019 to 2026 (2.9 TFSI engines)

  • A6 / A6 Avant / Allroad (type 4K2 / 4K5 / 4KA - C8) – model years 2018 to 2026 (3.0 TFSI / 55 TFSI engines)

  • S6 Avant / Sedan (type 4K - C8) – model years 2019 to 2026 (2.9 TFSI engines)

  • A8 / S8 (type 4N2 / 4N8 - D5) – selected versions with 3.0 V6 TFSI engine

  • Q7 / Q8 (type 4M / 4MN) – selected versions with 3.0 TFSI engine

Fitment guarantee and VIN verification

Every hose undergoes a pressure leak test and a detailed inspection of the quick-connect fittings before shipping.

Fitment / installation note: The 4K0 designation indicates universal A6/A7 chassis geometry (fitting both LHD and RHD versions). Using the original OEM pipe ensures it snaps securely onto the factory fittings without creating dangerous material stress or risking glycol leaks. Before purchasing, we recommend comparing the full OE number with the index (J) on the label of the old hose or verifying fitment using the vehicle's VIN.