Coolant Expansion Tank

The VW/Audi coolant expansion tank, also known as an overflow bottle, is a vital part of your vehicle's cooling system. It manages the expansion of engine coolant as it heats up, providing a reservoir to capture and store the excess volume. This genuine replacement part, manufactured in Italy, directly corresponds to OE part numbers 1K0121407F and 1K0121407A. Failure of the coolant expansion tank can lead to various issues, including coolant leaks from seams or cracks, difficulty in accurately reading coolant levels due to plastic degradation, and potentially engine overheating if the cooling system pressure is compromised. Over time, heat cycles and chemical exposure can cause the plastic to become brittle and prone to cracking. Specific fitments include various Audi A3, TT, and Q3 models, as well as Volkswagen Beetle, CC, Eos, Mk5, Mk6, Mk6.5, Passat, and Tiguan models. It is compatible with a variety of engine types, including 2.0T, 2.5L, 3.2L VR6, 3.6L V6, and TDI engines, across different drive types such as FWD and Quattro/4Motion.