The engine coolant (known also as antifreeze fluid) is a fundamental fluid for the engine that avoids dangerous freezing or boiling of the liquids circulating in the cooling system.

If the fluids in the engine freeze, they can’t reach every part of the cooling system causing some components to work at higher temperatures than what they are made to sustain. Also, the components are poorly lubricated and might seize. Frozen liquids can also swell and damage plastic and rubber pipes.

Coolant or radiator liquid are preferred to “antifreeze” to highlight the fact that the solution protects the engine both in winter and in summer.

Engine coolant: what do the different colours mean?

When it’s time to change the radiator fluid, we start wondering which one is the right one. There are numerous colours on the market: pink, red, blue, green, purple and yellow. To find the right one for your vehicle it is best to check the car maintenance booklet. The usual advice is to choose a radiator fluid of the same colour of the one already present in the car.

The different colours indicate the chemical composition of the liquid and they vary from manufacturer to manufacturer. Said composition results also in characteristics change. The blue one, for example, doesn’t not deal with low temperature as well as the red ones.

How does it work ?

The antifreeze liquid uses ethylene glycol, a substance that lowers the freezing point of liquids to around -45 °C so that it can stay at the liquid state even in situations of extreme cold. 

The fluid has also other additives that help prevent boiling or formation of foam in the system. After years, the liquid loses its characteristics and it doesn’t perform the required tasks efficiently. 

When does it need replacing?

Checking the antifreeze fluid is an operation to be performed regularly to avoid major and costly damage to your car’s engine.

As with any other vital fluid for the car, all the information for replacing the antifreeze liquid is indicated in the car maintenance booklet. Normally, this happens every 2 or 4 years.

It is always a good idea to check the antifreeze liquid when you are about to leave for a long journey or the climatic conditions are challenging.

It is also better to refer to a mechanic as they are equipped with tools such as the hydrometer that analyses the liquid.

The coolant replacement operation has a really low cost and it is worth doing it regularly. Damage caused by an oversight or a do-it-yourself top-up could cost you dearly. 

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Can you mix water and antifreeze liquid?

This operation is often recommended by the manufacturers. In fact, we also find it in the indications on the product packaging. Usually, the topping up percentages indicated correspond to 50% liquid and 50% water. Try to always keep this ratio as the mixture can get over diluted which would cause loss of its anti-rust, anti-freezing, anti-boiling and anti-foam characteristics.