4G0121081ED Coolant Breather Hose for Audi A6 C7 A7 Quattro 3.0L V6 2016-2018

◆ This coolant breather hose is a direct replacement for the original Audi unit, designed to balance coolant volume and pressure within the expansion tank circuit as temperatures change .

◆ The OEM reference number is 4G0121081ED. An interchangeable or alternative reference commonly listed is 4G0121081DL .

◆ The hose is engineered to OEM standard dimensions for direct fitment into the cooling system without modification. It is constructed with a heat-resistant hard plastic pipe and EPDM rubber sealing rings at both ends .

◆ It is specifically designed for the Audi A6 (C7) and A7 (including Quattro variants) equipped with the 3.0L TFSI V6 supercharged engine, covering model years from approximately 2016 through 2018 .

◆ This product is a coolant overflow/breather hose manufactured to meet original quality standards for fit, pressure balance, and durability.

◆ Part Number: 4G0121081ED

◆ Alternative Reference: 4G0121081DL

◆ Component Type: Coolant Breather Hose / Expansion Tank Overflow Pipe

◆ Vehicle Make: Audi

◆ Engine Compatibility: 3.0L TFSI V6 (Supercharged)

◆ Material: Hard plastic pipe with EPDM rubber seals

◆ Color: Black

◆ Placement: Front engine cooling system / expansion tank circuit

◆ Note: Only fits 3.0L V6 gasoline models; not compatible with 2.0T, 4.0T V8, diesel, or RS variants

◆ OEM Standard Fit: Manufactured to exact original specifications for a direct, hassle-free replacement .

◆ Pressure Balance Function: Balances coolant volume and system pressure during temperature fluctuations, preventing coolant loss and overheating .

◆ Durable Construction: Heat-resistant plastic pipe with EPDM rubber seals provides resistance to coolant corrosion, cracking, and slow leaks .

◆ Leak-Tested: Each hose undergoes 100% air-tightness leak testing for reliable performance .

◆ Audi A6 (C7) 3.0L TFSI V6: 2016–2018

◆ Audi A6 Quattro 3.0L TFSI V6: 2016–2018

◆ Audi A7 3.0L TFSI V6: 2016–2018

◆ Audi A7 Quattro 3.0L TFSI V6: 2016–2018

◆ Note: Verify against your vehicle‘s original part number and engine code before ordering. This part is not compatible with 2.0T, 4.0T V8, diesel, or RS models .

Q1: Is this a genuine Audi part?

A: The 4G0121081ED reference is the original equipment part number. Both genuine Audi/VW and aftermarket equivalents are available that match the original fit and function .

Q2: How do I confirm if it fits my vehicle?

A: Check your vehicle‘s existing hose. If it is stamped with 4G0121081ED or the alternative reference 4G0121081DL, this replacement will fit. Also confirm your vehicle is an Audi A6 (C7) or A7 with the 3.0L TFSI V6 engine, produced between 2016 and 2018 .

Q3: What is the function of this hose?

A: This breather hose connects the expansion tank to the cooling system, balancing coolant volume and internal pressure as temperatures change. It helps prevent coolant overflow loss and contributes to maintaining proper engine operating temperature .