Most common petrol myths, busted

Black car without number plates parked at petrol station


Posted June 15, 2023

There are plenty of tall stories, myths and theories out there when it comes to petrol. Read on as we separate fact from fiction to bust the most common petrol myths.

So we all know it’s cheaper to buy petrol on a Tuesday, right? Wrong.

The cheaper-on-a-Tuesday myth is just one of the common misconceptions many of us have about petrol – along with manual cars being more economical to drive and E10 fuel being bad. So, next time you want to save on fuel on a road trip or drive in the most fuel-efficient way, don't fall prey to these six common petrol myths.

Searching for the cheapest fuel near you? Try the free arevo journey planner app: its Fuel Finder feature provides regularly updated fuel pricing from retailers across Victoria. RACV Members can also save up to 13 cents per litre on fuel thanks to a new stackable discount.

Australia's top six fuel myths


E10 fuel is bad for your car

E10 fuel is regular unleaded petrol that's blended with 9-10 per cent ethanol. It's usually the cheapest option at petrol stations. But E10 fuel tends to get a bad rap, with some Australians believing that it can cause problems with your car.

That might have been true when E10 fuels were introduced about 20 years ago, when older cars' engines would get dirty and cause issues with ethanol fuel. Nowadays, though, technology advances have ensured that most vehicles can safely use E10 fuel. In fact, many cars on Australian roads are designed in Europe and Asia, where there is a large ethanol usage.

You can check if your car is compatible with E10 fuel on the inside of your fuel filler flap, which should list the lowest-grade fuel you can use in the car (anything higher-grade is also fine), or on the manufacturer's website.

Running on almost empty can ruin your engine 

This myth is another holdover from several decades ago, when older vehicles could have water or contaminants stuck at the bottom of their fuel tank. But in modern cars, petrol is pumped from the lowest point in the fuel tank, so whether your car's tank is full or empty makes no difference to the petol quality.

arevo fuel price comparison app

Don't buy into refuelling myths. Image: Getty

Country petrol prices are always higher than in the city  

It's true that country petrol prices are often higher than in the city, but not always.

Regional fuel retailers generally sell less fuel than metropolitan retailers, while transporting the fuel large distances into regional areas can be quite expensive. As a result, country petrol prices generally remain pretty steady.

That said, regional prices do drop below Melbourne prices on occasion. There are times when Melbourne’s price peaks are substantially higher than regional prices. Regional drivers coming to Melbourne should always check city prices to see if it’s cheaper to fill up at home.

Tuesday is the cheapest day to fill up, while fuel prices hike before long weekends

The days of predicting the cheapest petrol day are gone. In the past, the price cycle was exactly a week long and everyone discovered “cheap Tuesdays”. But since 2013, the price cycle has varied from nine days to up to two months. It's no longer possible to predict the peak-to-low petrol price cycle and which day fuel will be the cheapest.

"Drivers can use RACV’s fuel price monitor on the free arevo app to find the cheapest petrol prices near them," says RACV Head of Policy James Williams. "The interactive map – which you can sort by distance, lowest price or preferred brand – updates every 15 minutes for accurate pricing."

Retailers never sell below the wholesale price of petrol 

Petrol stations do sometimes sell below wholesale prices to match or beat their competition. Drivers who shop around put pressure on retailers who want to keep customers. This competition triggers the slow discounting cycle, where retailers reduce the price by one to two cents a day until they get to or below the wholesale price. Often the super-low price lasts only a short time and the price spikes upward again.

The retail price may also be lower than the wholesale price due to the fuel supply chain and the delay between leaving the terminal gate and selling that fuel at the pump.

Manual cars are more economical than automatics 

Manual cars used to be more economical than automatic vehicles, but not any more. When automatic transmissions were new (and quite basic), they typically increased fuel consumption and reduced performance compared to a manual driver who shifted gears efficiently. But modern automatic transmissions can match or better a manual’s economics, as technology like electronic shift control systems now outstrip the average driver's ability with a clutch and stick shift.

Access your exclusive RACV Member fuel discount.
Activate your fuel voucher →