Do you know what it really means when the fuel light in your car goes on? Maybe you’ve heard that you get more mileage when you fill your tank in the morning? There was even a rumour that your car will go faster if you put jet fuel in it – sounds exciting, but is it true?

Colin Harding is a senior engineer with the Ford team that designs what a driver sees in the ‘instrument cluster’ where the speedo is. Harding and his team are experts in everything related to mileage, and so they spend a lot of time deliberately trying to make cars run out of fuel.

Here, Harding debunks five of the most common myths associated with fuelling your car:

1. Filling your tank in the morning gets you more mileage

Good try, but no.

The theory behind this myth is that petrol expands with heat – which is true – so if it’s cooler, you can fit more of it into your tank. But the fact is fuel is stored in tanks below ground where the rising temperature of the day plays no part in the density of the petrol, so fill up whenever you wish.

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2. Letting your fuel run low is bad for your engine

Nope.

“The common misconception here is that if you drive on ‘the fumes’ your engine will begin to ingest ‘rubbish’ or sediment-littered fuel from the bottom of the tank. But the fuel tank is designed so that the fuel pickup always sips from the bottom of the tank, meaning it is always able to draw fuel. Contrary to popular belief, when you’re running low the quality of the fuel being used by the engine is no different to when the tank is full.”

3. Premium fuel makes your non-premium car run better

False.

When we pull up to the pump, there are more options than ever; words like power and premium, and enough different oils and lubricants to drive anyone mad. And while it may be more expensive, it isn’t any cleaner or purer than regular fuel.

“While it is less combustible, which benefits powerful performance engines, it won’t benefit the vehicles of most daily drivers as all types of fuel have to meet the same standards.”

4. My range readings are wrong

Unlikely

While the fuel gauge tells drivers exactly how much fuel is in the tank, range readings are calculated based on longer term driving patterns. “If, for example, you drive on the highway for two hours using six litres of fuel per 100 kilometres, then leave the highway and begin city driving at 12 litres per 100 kilometres, the instrument cluster will take a little bit of time to adjust to the new driving conditions. For this reason, the readings will temporarily change at a faster rate than one kilometre for every kilometre driven.”

5. Jet fuel makes your car go faster

It most certainly does not.

Conventional petrol engines can’t combust kerosene (jet fuel). So, if you’re planning on winging it any time soon, stick with your car’s regular fuel or you’ll be in for a long delay.

It’s not always clear where myths come from, how they catch on, or why misconceptions can sometimes become the perceived rule.

Since most vehicles nowadays are precision engineered to offer the optimum driving experience and good fuel efficiency, if you have additional questions about your car’s fuel’s consumption, it’s recommended that you consult an authorised dealer or service centre.