Coolant

Coolant is a mixture of water and anti-freeze with special additives that helps dispel heat while preventing the water in the radiator from boiling or freezing. Since the amount of heat generated by burning gasoline, the coolant is greatly relied upon to ensure the car is functioning properly. As the coolant travels through the engine by the water pump, it absorbs any excess heat while cooling the water and protects various parts of the engine with its anti-corrosive properties.

What can go wrong?

Water is not sufficient enough to keep the system cool as it will eventually boil or freeze due to extreme temperatures. Without coolant, the engine would overheat extremely fast and the internal combustion would destroy it, deeming the system useless.

What can you do?

When the coolant level is lower than the line indicates on the reservoir, add a 50/50 mix of water and coolant until it reaches. Although coolant doesn't necessarily expire, the additives within it do, which will expose the engine and radiator to corrosion. Always get a coolant flush to renew the fluid to guarantee its proper protection when recommended by a service advisor.