How do you know when your car needs coolant?

Close up of car engine, hands pouring coolant into the system

Keeping your engine cool is a critical factor in ensuring your vehicle runs efficiently and does not face the risk of overheating and causing potential damage to vital components that can be extremely costly to repair.

As a result, knowing when to add additional coolant to your engine is a must for all motorists. There are some tell-tale signs that your vehicle may be running low on coolant, so take the time to read our handy top tips below.

What are the signs your car needs a top-up?

Most new cars will have automatic systems to detect excessive heat due to a lack of engine cooling, but for older models, drivers must keep a close eye on their engine and ensure regular maintenance to top up any engine fluids.

A dashboard warning light will illuminate to warn the driver that water/coolant levels are getting low, while a rise in the temperature gauge is also a first sign that there might be a problem. Billowing steam, a hot bonnet and a lack of control over the interior heating are also signs of temperature issues with the engine.

An automatic engine cut-off is installed in most new vehicles, which is designed to prevent damage to key engine parts when temperatures spike. However, if your car is not fitted with this type of system, the onus is on the driver to keep coolant levels effectively topped up.

When you fail to recognise the warning signs that your car has inadequate cooling, you risk damaging some of the most important parts of your vehicle’s engine.

Due to the high temperatures created when the car is running, poor cooling can result in severe damage to the water pump, head gasket, cylinder and piston timing, cylinder head, warped or bent connector rods, or even crank failure.

Failure to properly maintain your vehicle can even result in the car becoming a write-off, so vigilance is key when it comes to topping up coolant.

How to fill up your engine’s coolant

The process of topping up your engine’s coolant is actually relatively straightforward.

First, ensure the engine is cold, the handbrake is applied and the vehicle is in first gear, then raise the front of the vehicle on jacks and ensure the back wheels are chocked to prevent any movement.

Next, place a container below the engine’s radiator and undo the drain valve and remove the filler cap. Now, flush the system as many times as necessary to ensure it is completely empty.

Locate and remove the reserve coolant tank from the vehicle and drain any remaining fluid, then replace the tank securely and close the drain valve.

Refill the system to the base of the filler neck with the correct coolant for your vehicle (specifications can often be found in your vehicle handbook).

Finally, bleed the system of all air by briefly running the engine, turning it off and topping up once more. Repeat this process until the coolant level remains static when the engine has been turned over. Securely replace the radiator cap to complete the process.

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