Choosing the right type of engine coolant for your car | AutoGuru
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Engine coolants - not just coloured water


Updated 9 Oct 2019


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Back in the day, for those of you old enough to remember, youngsters would often top up their cars’ radiators or overflow bottles with tap water.

They could get away with this behaviour for a while but eventually, a few months down the track, that water ended up looking like a mud puddle and their cars were, shall we say, not running at peak performance.

Today’s vehicles are so technically developed that we must look after all their systems, including engine cooling, a bit better than that!

What is engine coolant?

Coolant is, generally, a blend of water and additives that is pumped through, and draws heat from, the engine, flowing through the car’s cooling systems and helping to keep the engine working at an ideal temperature.

The coolant flows in a continuous loop around the engine, including through the radiator where it is itself cooled.

The additives in the coolant, along with the system pressure, give it its higher operating temperature (ensuring it does its job in the furnace of the engine), and they also inhibit rust and corrosion.

The different types and mix of these additives is what determines the type of coolant you should use.

There are three major types of coolant technologies: IAT (Inorganic Acid Technology) coolant is the traditional coolant mix which is often green and is generally suited to older model vehicles; OAT (Organic Acid Technology), has a different chemical composition, is often red and offers a much longer service life.

HOAT (Hybrid Organic Acid Technology) is, as the name suggests, a mix of IAT and OAT components.

A waterless coolant is also available.

It’s more expensive than the regular stuff and is most often used in motorsports, for high-performance vehicles, and in older classNameic cars.

The colour of the coolant is quite important. You may have noticed they come in a variety of disturbing hues, from green to red to purple and even pink.

While the colour can be an indication of what type of coolant you currently use, it’s not a guarantee and it is best to check the info on the bottle and know what your vehicle’s manufacturer has recommended.

A general rule to follow, however, is to never mix different colour coolants.

When it comes to your engine cooling system and coolant levels, you can expect your mechanic to check them at service time. Keep in mind that radiators and hoses can begin to leak unexpectedly even after visual inspection by your mechanic, although most workshops have a pump-like gadget that can pressurise your system to ‘load it up’ and test to find any leaks.

Your mechanic can test your coolant’s quality to ensure it is protecting your vehicle, but its good practice to renew it occasionally as just topping up at service time can deplete its effectiveness.

Your mechanic wants to do the right thing and will use a product that has been tested and proven to meet industry standards as it is essential to the long-term protection of an engine cooling system.

Not too sure where to start with coolant? Not a worry!

AutoGuru can help find you a great local mechanic to make sure your car has enough of the correct type of coolant to keep it running happily. 

If you think you might need to get your car inspected, you're just a couple of clicks away from getting quotes.  


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