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What Does Coolant Do?

In the world of keeping your car running smoothly, coolant is right up there in importance beside engine oil but is hardly ever mentioned. It’s an under-appreciated fluid that really makes a difference and has some really interesting qualities.

First though, what is the job of coolant?

Coolant is the forbidden cordial that runs through your engine to keep everything from overheating. It uses the principles of heat transfer to take heat away from the motor and gearbox, transfer it to the radiator and dissipate it into the world. While that might seem like a mouthful, the basic thing you need to know is that it takes heat from the engine and makes it someone else's problem.

The next question (for someone with a scientific mind) might be, "well, doesn't water do that job too?"

The interesting thing here is that coolant is actually not the best liquid for heat transfer and can easily be replaced by water in most cases. However, there are a few more sides to coolants personality that really make it a first date champion.

The first is corrosion. While you may be able to easily replace the coolant in your motor with water, water can cause serious amounts of corrosion over time eroding the insides of the engine and clogging passages where coolant should flow. The long-term effects of this are actually quite bad and can seriously weaken a motor and even cause overheating through the blocked flow.

Coolant, on the other hand, provides rust prevention.

Another interesting facet of coolant is actually derived from its other common name, "antifreeze". While this name doesn't really make sense to most Australians, coolant provides an extremely important service in cold climates.

As you might remember from school, water is one of the few things in the universe that expands when frozen. This expansion can happen when a car is left overnight in sub 0˚

temperatures and can cause the engine to split from the pressure inside.

This is where coolant/antifreeze comes in. Much like how alcohol doesn’t freeze in the freezer, some of the chemicals in coolant also prevent freezing. This means your motor is safe throughout the winter.

So, should you replace your coolant?

Well, yes. It is a good habit to replace the coolant in your car fairly regularly OR to make sure that you are topping up your coolant to the correct dilution. This isn’t necessarily because the coolant stops doing its job as well but actually as a way to clean out any gunk or corrosion that forms in the motor over time.

Remember, if you have any questions about the coolant in your car, you can always ask one of our Kashy mechanics.


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