How to check your car’s antifreeze

Antifreeze is a chemical solution which is added to the water that flows around your car’s engine and through its radiator. It performs an important function all year round: in the winter, it lowers the freezing point of the water in the cooling system to prevent it icing up as the temperature drops.

In the summer, it is generally referred to as coolant – even though the mixture is precisely the same – because it raises the boiling point of the solution, helping it to stay as a liquid for longer, so it can flow around the engine and be cooled as it is pumped through the core of the car’s radiator.

How to check your car’s coolant

It’s not hard to check your car’s antifreeze, although doing so requires a specialist tester so it might be worth speaking to your local garage to do this for you.

Armed with a coolant tester, which cost around £10-15, you’ll be able to test your car’s antifreeze throughout the year, reducing the likelihood of a costly breakdown.

Firstly, take a look in your owners’ manual to help locate the antifreeze reservoir (also known as the coolant tank). First check that the fluid is between the ‘min’ and ‘max’ marker. If not, it’ll need topping up. If the level is too low, there won’t be enough coolant in the system to be effective; if it’s too high the expansion of the fluid could cause damage to coolant pipes or hoses.

Secondly, you’ll need to check the effectiveness of the antifreeze, so that it protects against both low and high temperatures. A reusable coolant tester or single-use coolant tester strips are cheap and easy to use.

You need to ensure you use the correct antifreeze for your car, so speak to your local dealership. If you need your antifreeze replaced, speak to your local garage – the job isn’t particularly complicated, but it can be messy and you’ll need to dispose of the old fluids properly as they can’t be flushed down the drain.

What Car?’s guide to driving in winter

How to check a car battery
How to check a car tyre: pressures and tread depth explained
How to change a car headlight bulb – a step-by-step guide
How to replace windscreen wipers – and check screenwash
What to carry in your car during winter
How to drive in winter
What to do if you get stranded
Should I fit winter tyres?

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