Antifreeze does not expire, but the incorporated additives used to prevent engine corrosion have an expiring period. In this regard, it is essential to replace the antifreeze in line with the manufacturer’s expiry guidelines. Ethylene glycol is poisonous to animals and humans, which necessitates strict adherence to the producer’s safety and disposal advice. An additive that is not mixed with water tends to last longer than pre-mixed coolants. Additives begin to degrade when poured into a car and following its reaction with other liquids. When one fails to drain degenerated antifreeze from the vehicle, corrosive deposits may begin to form in the engine. One may purchase an antifreeze tester to determine the quality of a coolant before use. In brief, a sealed bottle of the additive has an indefinite shelf life and once opened, it can be kept for many years if stored in the original container.