Buy OEM Audi Part # 8W1121405N (8W1-121-405-N, 8W1121405K). Engine Coolant Reservoir. 2.9 LITER, MAIN. 3.0 LITER. 3.0 LITER, MAIN. CONVERTIBLE, 3.0 LITER, MAIN. Coupe, 3.0 LITER, MAIN. MAIN. RS5. S4

Engine Coolant Reservoir. Expansion tank.
A container that holds Engine Coolant.

Engine Coolant Reservoir

Fits RS5, RS5 Sportback, S4, S5, S5 Sportback, S7 Sportback

2.9 LITER, MAIN. 3.0 LITER. 3.0 LITER, MAIN. CONVERTIBLE, 3.0 LITER, MAIN. Coupe, 3.0 LITER, MAIN. MAIN. RS5. S4. S5.
Engine Coolant Expansion Tank - Repair or Replace
A failed expansion tank can cause the cooling system in your Audi to leak antifreeze, or it can cause your engine to overheat. If you're losing coolant, contact our service department to avoid engine damage.