I'm a driving expert

A DRIVING expert has revealed why you shouldn't touch a secret button hidden in your car.

The motors whizz, known as Chequanlaosi on YouTube, posted a video explaining how the little-known feature should only be used when people understand what it's for.

The savvy social media star highlighted that turning on the air circulation in your vehicle can help your health, but shouldn't be overused.

He said: "In the summer, the car will emit formaldehyde after being exposed to the sun.

"After we get in the car and turn on the air conditioner, we must turn on the outer circulation for 10 minutes, and then turn on the inner circulation after the formaldehyde is exhausted."

Formaldehyde is used in heavy industry and for embalming but is known to cause cancer through long-term exposure and is toxic to humans.

In small doses, it can cause coughing, headaches and eye irritation.

When it comes to cars, the colourless, odourless gas is a byproduct of engine combustion, so using air recirculation to disperse it can reduce drivers' exposure.

The recirculation button pushes the cool air already in your air conditioning system back through the cabin.

It usually has a dial to vary power and is marked out by a symbol of a car's outline with a curved arrow within.

It can take the strain off the AC by reducing the amount of warm air taken in to be cooled and helps reduce fuel consumption in the process.

Additionally, Chequanlaosi recommended switching the system back on when sitting in heavy traffic to disperse pollution fumes.

However, it should only be used in hot weather or when using the air conditioning.

When it's cold, keep your car's default fresh air mode on and don't touch the recirculation button, as using it can cause damp and humidity in the car and fog up the windows.

If you have a newer car and can't spot the button, you likely don't have one as more recent models tend to have sensors that regulate the process automatically.

It comes after an expert mechanic with decades of experience revealed the popular country that drivers should not buy cars from.