Depending on where you live, you might choose a different name for it. In northern climes, you likely call it antifreeze, while your cousins in the warm south probably call it coolant. In reality, you are both talking about the same stuff. Coolant is a really neat liquid. Not only does it prevent your engine from freezing, but it also helps the engine run cooler in the heat.
Modern engines are made up of many different types of metal, that do not like to get wet together. These dissimilar metals create all sorts of acids and corrosion when they are joined and then exposed to heat, vibration and moisture. This is not good, as it essentially means that your engine, cooling and heating systems are being eaten from the inside out.
Coolant is made from a glycol base, that has all sorts of different chemicals added to it. Those additives work together to prevent the corrosion from happening. They also act as a lubricant for moving parts like the water pump.
The problem is that these additive packs don’t last forever. They actually begin to break down after a couple of years, so they aren’t doing their jobs anymore. This can lead to overheating, premature water pump failure and even freezing problems in cold climates. For this reason, the coolant in most cars should be changed every 2 years.
Some manufacturers have chosen to use coolant with different additive packs that can last up to 5 years. Just like any new technology, long life coolants have their detractors. There are some who believe that the longer life coolants actually cause more problems than they fix, so the jury is still out on that one.
How often should you change your coolant? Well, the obvious answer is to change it as recommended by the vehicle manufacturer. Some manufacturers though, don’t actually list coolant in their recommended maintenance! Does that mean you don’t have to change it? No way. It means they were trying to keep the maintenance costs down for marketing purposes! When in doubt, change your coolant every 2 years. If your car calls for long life coolant, it might not be a bad idea to change it more frequently than required as well, just to be safe.