Filling car coolant

How to Add and Change Car Coolant

Coolant is the magic bright liquid that stops you from having an expensive bill at just the wrong moment, but did you know that there are a wide range of these elixirs out there, and you need to make sure that you’re using the right one. But what do you do when it starts to run out? Let us talk you through the process of keeping your coolant levels in the right place.

Filling car coolant

What Coolant Does My Car Need?

For most cars on the road you will be looking for a silicate-free, organic acid technology (OAT) antifreeze. Antifreezes made to this specification protect your engine parts from corrosion much better than those with silicate, meaning your engine parts last longer. However, if you are driving a car that was manufactured before 1998, there is a strong chance you will be looking for an antifreeze that isn’t OAT and does contain silicate.

To be certain you are getting the right coolant, be sure to check your owner’s manual.

How to Know Coolant Needs Topping Up?

For most modern cars you will get a warning on your dashboard to let you know there are problems with your levels. If it does come on then you should bring the car to your nearest garage as soon as possible as most modern cars have sealed cooling systems, making it even harder for you to maintain yourself. 

However, if you want to Checking your coolant levels only requires you to open the bonnet, and, no, you don’t need to remove your radiator cap. Once you’ve popped the bonnet, make sure you’re looking at the right tank, as adding antifreeze to your screen wash, brake fluid or power steering tank will likely mean your next trip is to the garage.  If you’re not sure which tank to look for, consult your vehicle handbook. You will be able to see the level through the side of the tank, and it should be between the min and max markers on the side – if it is close to the min line or even below, then you should top the liquid up.

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Where Does Coolant Go in a Car?

Your coolant will sit in its own designated reservoir, which is usually a large, opaque case within the engine bay, and you can usually tell it is the right container as it will have a warning on the cap telling you not to open it if the engine is hot.

How to Top Up Coolant in a Car

Topping up your coolant isn’t too difficult, but does require a bit of caution, as if you get things slightly wrong, you could be in for a painful time, both in terms of causing extra damage and actual, physical pain.

  1. Make sure your car is parked on a flat surface and given time for the engine to cool down. If you try to open the coolant reservoir while it is still hot, the pressure will cause the coolant to burst out like a geyser, potentially scalding you in the process.
  2. Remove the cap of the coolant reservoir and, using the coolant outlined in your owner’s manual, top the liquid up.

How to Change Coolant in a Car

Changing coolant is much like topping up your coolant, but has a few additional steps to be aware of first.

  1. Once again, make sure your car is parked on a flat surface and the engine has cooled down.
  2. Raise your car up using a jack, and secure it with jack stands – never get under a car that is only held by a jack.
  3. Remove any shielding under the car.
  4. Grab a container, and place it underneath the radiator.
  5. Undo the drain valve and begin flushing through all the liquid.
  6. Find the reserve tank, remove it from its holder and drain any coolant remaining into your container.
  7. Replace the drain valve and refill with the correct coolant up to the base of the filler neck.
  8. For some cars, you may need to briefly run the engine, then top up coolant, replacing the radiator cap and then run again until the cooling fan turns on, checking levels and topping up accordingly. Check your owner’s manual for the correct procedure for your car.

How Long Does Coolant Last in a Car?

The gap between coolant changes will depend on how often you drive your car, and how far you drive it when you do. The temperature also makes a difference and if you are doing a lot of driving during the summer months it’s worth keeping a closer eye on your levels. The general rule of thumb, however, is that you should change your coolant every three to five years.

A group of travellers wonders what to do after their car overheats.

How Much Coolant Does My Car Take?

The majority of cooling systems will take around five litres of water, but, as always, this can vary from car to car. Most coolants are sold in a range of sizes, so you can tailor your purchase to the specific amount that you need.

Can I Drive a Car Without Coolant?

Your car can physically drive without coolant, but it’s not going to go very far. The coolant helps regulate the heat in your engine, and without it, there is nothing to keep the engine temperature down, meaning your car will quickly overheat and you’ll be paying for a new engine much sooner than you’d have hoped for.

If you’re driving a modern car, then your car’s Engine Control Unit will likely turn your car off to prevent any lasting damage, giving you a chance to get your car towed to the nearest garage. If you’re in an older car, however, an overheating engine could lead to your engine seizing or blowing a gasket.

The most common component failures in wrong temperatures are water pumps, head gaskets, cylinder heads, connector rods and crank failure – all of which will see your bank account significantly emptier after they’re repaired.

Can You Put Too Much Coolant in a Car?

If when filling your coolant reservoir you find yourself going above the maximum line, then this could result in the coolant rising to the top of the reservoir as it expands in the heat, and emitting out of the cap – creating steam and in extreme cases can cause electric damage if any of the liquid comes into contact with the engine wiring.

Can I Put Water Instead of Coolant in My Car?

Coolant is produced to both raise and lower the boiling and freezing points respectively, something that is not afforded to you if you just have a reservoir full of water being pumped around your engine. Water also won’t absorb the heat as well as coolant, and just using water alone could result in your engine overheating. In an emergency, and for short distances, you could use water, but we wouldn’t recommend it.

For more tips on keeping your car on the road, visit our Car Care hub, offering guides on everything from how to change your oil to preparing for an MOT.

If you’ve had an engine issue as a result of poor, or even no, coolant, then you may find that it’s much quicker, easier, and economically sensible to sell the car for scrap. Our team of dedicated and friendly experts are on hand to get you the very best deal possible for your car, and through our nationwide network of buyers, can guarantee you won’t find a better price.

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