4E0121403C 4E0121403G Coolant Radiator Expansion Tank for A8L D3 4E 2002-2010 for A8/S8 D3 2006-2010 Coolant radiator expansion tank designed to fit specified vehicle models within the given year ranges.This component is engineered for integration into the vehicle's cooling system, providing a reservoir for coolant to expand and contract with temperature changes.Constructed to meet specifications, it supports consistent thermal management during.The tank includes necessary fittings and connections for straightforward installation in compatible vehicles. Disclaimer of Affiliation: This is an aftermarket component.Brand and model mentions are for illustrative compatibility only.