How to Check and Top Up Your Coolant


To avoid a potential car break down, we advise motorists to check their car’s coolant level weekly.

Before you get started there are two important things to remember:

  • All modern cooling systems are sealed and as a result they shouldn’t ever really need topping up between car services provided everything in your vehicle’s engine is functioning correctly.
  • It’s a pressurised system and as such should only be checked or topped up when the car’s engine is cold.

Identifying your vehicle’s cooling system

Your car’s cooling system will usually have a coloured cap, however the best practice if you don’t know where it sits within your vehicle’s engine is to check the car manufacturer’s manual.


Checking your vehicle’s coolant level

In most cars, the coolant tank will have a maximum and a minimum mark on the exterior. More importantly your vehicle’s coolant tank is made of a transparent material so that you don’t have to remove the cap to check it. The coolant should be between the maximum and minimum marks.

How often should I check my car’s coolant level?

To avoid a potential break down, we advise motorists to check their car’s coolant level weekly. This weekly check, which should form part of your regular vehicle maintenance activities, will allow you to spot a coolant leak and pre-empt a break down. An undetected coolant leak will cause your car to overheat when you drive it.

For more information on what to do if your car breaks down click here.

Topping up your vehicle’s coolant tank

If you notice that your vehicle’s coolant level has dropped it’s important to take it to a good car mechanic. We recommend an AA or SIMI appointed garage for this. To find an AA appointed garage in your area click here.

In the meantime, to prevent your car breaking down you will need to top up the coolant level. To do this, first and foremost you need to make sure that you’re using the correct coolant.  Secondly you should make sure that the car’s engine is cold.

Most antifreeze will need to be added to water before they are added to your car’s coolant system. The general rule of thumb tends to be 50:50 but you should check your vehicle’s instruction manual to make sure you’ve got the right mix.

When you’re sure your car’s engine is cold you then need to open the coolant tank’s cap. There might be some residual pressure in there so you might hear a little hiss. You’d then take the container with the suitable anti-freeze mix in it, using a funnel if needed and top your vehicle’s coolant level up until it reaches the maximum mark making sure not to overfill it. Going past this mark means you’ve taken away some of the room the coolant needs to expand as it’s an expansion tank.

In the case of a car break down, AA Members can report it through our AA App or call us on 01 617 9560. With AA Membership we fix 8/10 cars on the roadside, making sure you get back on the road as soon as possible.

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