443121321 : Expansion tank cap for Audi 100 and 200

This expansion tank cap is intended for Audi 100 and Audi 200 produced between 1979 and 1991. It ensures a tight seal of the expansion tank in the cooling circuit, a part subject to wear and thermal stress over the years. Its colour, blue or black depending on supplier deliveries, may vary but does not affect the function or fitting in any way. Replacing this cap is part of a thorough restoration or maintenance approach for an Audi classic vehicle.