How To Replace A BMW E39 Coolant Expansion Tank (Six-Cylinder) ↗
Six-cylinder E39 expansion tank swap: drain, unclip hoses and the level sensor, unbolt the tank, transfer the sensor and fit a new cap and bleeder. Only hand tools and jack stands needed.
Tools mentioned: Screwdrivers, drain pan, jack and stands
Level switch 61318360876 and cap 17111742231 are in the article's parts list.