Cars are complex beasts which have evolved mightily in the past several decades. These two factors mean this area is ripe for misinformation and rumour. What once was accurate is now, thanks to the timeless march of technology, not so. Also, there are some beliefs that have never been true but have been kept on life support by that master promulgator of myths and falsehoods – the internet.  

So, here we lay to rest 5 common car myths.

Premium fuel is always best

Premium unleaded fuel has been optimised for high performance engines; they have added protectants and cleaners that certain engines need to function well. Your Mazda 3, while a wonderfully engineered vehicle that can very ably move you from point A to point B, does not have a high performance engine and does not need 98 octane fuel.

To be safe, take a look in your car’s manual or inside the fuel cap door, where it will stipulate what petrol your car requires. Higher octane fuel won’t damage cars that don’t need it, but it won’t provide any benefit either. On the flipside, you should never use a lower octane fuel than what is recommended, as this can and will cause damage to your engine.

When you replace one tyre, you should replace all tyres

Tyres aren’t cheap, so replacing them when they still have plenty of tread and are capable of doing their job is something we’d like to avoid. Fortunately, you can replace individual tyres as needed so long as the new addition is the same brand, model and size as the rest. This is not an uncommon practice as tyres can wear at different rates dependent on driving habits and whether the car is front or rear wheel drive.

Often, worn rear tyres are removed, the front tyres are moved to the rear and a new pair of tyres are put on the front axle. 

Air conditioners waste fuel – wind down the window instead

This is true to a point, after which it becomes a lie. Here’s why. Air conditioners do burn through fuel, that’s no mistake. According to studies, turning the air conditioner off and winding down the windows is better for fuel economy… up until 80km/h.

Faster than 80km/h, the drag becomes so strong and the aerodynamics of the vehicle are so compromised that fuel economy drops below what it would be if the windows were up and the air conditioner on. Plus, who wants the racket of the wind in your ears at freeway speeds?

Larger cars are safer in a crash

It seems logical that you’d want to be in the heavier car when involved in a collision. After all, when an 80kg footballer crashes into a 110kg opponent, we know who is coming off second best. But, this doesn’t tell the whole story.

If a large car and a small car collide, and both have the same ANCAP safety rating, it’s likely the larger car fares better. However, if the same two cars separately hit a large, immovable object (like a retaining wall), the larger car would be worse off due to its greater weight and energy.

When it comes to safe cars, forget size and think about what sort of driving you’re going to be doing and what suits you best. For instance, if you’ll be doing mainly city driving, go for a smaller model. Once you’ve made this decision, then select the safest car as per ANCAP recommendations that you can afford.

I need to have my car serviced at the dealership or my warranty is void

Wrong, and the ACCC is very clear and strong on this point. Any qualified mechanic can service your car and fill out the log book as long as quality parts are used – without voiding your warranty. Shady car dealers have always been sneaky on this point, implying you need to have your car serviced with them – and pay the exorbitant fees. But it’s simply not true.

In 2016, a survey by Choice found that 50% of car owners thought they had to get their cars serviced at the dealer. It’s time this lie was put to bed. It’s your choice where you take your car, so pick a mechanic you can trust (ahem… like us).