Expansion Tanks
Critical part of a complex and comprehensive automotive cooling system that’s designed to keep the engine operating at exactly the right temperature.
In the sealed cooling system that’s present on most cars, it is
partially filled with air which provides a ‘cushioning’ effect that allows the heated coolant to
expand without causing the cooling system to fail. The expansion tank affords an
easy visual way to keep an eye on the cooling system of the vehicle, because if the level in the expansion tank drops, there may be a leak somewhere, either in the pipework or in an engine gasket.