Car maintenance: How long does petrol last?

22 July 2020

The lifespan of a tank of petrol depends on a few factors, including how and where it’s stored. You may be tempted to load up on fuel when prices are low . But remember, petrol goes bad. Running your car on old fuel reduces performance—it could even damage your engine!

In your tank

How long will it last?

Petrol typically performs at its best for up to a month in the tank. Though, you can extend its life a little by restoring evaporated components—just add 1/3 of fresh fuel.

It’s hard to come up with specific timeframes for how long fuel is good for, as lots of external factors — including how long it’s been sitting in the petrol station fuel dispenser — are involved. To be safe, aim to use your fuel within a few months. Stale petrol can corrode your engine and fuel system. And owners of older cars beware: your carburettor can become coated in gum. If your car is sitting unused, invest in a fuel stabiliser. It prevents unused fuel from going stale for up to 12 months.

While you’re building that car maintenance toolkit, consider Suncorp’s Comprehensive Car Insurance. We’ll cover you for accidental loss or damage, to both your car and other people’s property. If you add Roadside Assist as an optional extra, we’ll be there to help if you’re ever stuck in Woop Woop — and yes, that includes emergency fuel delivery. Sign up online today and get $50 off!

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How to know if petrol is stale

Look out for these indicators:

  • You have trouble starting your car
  • Your car stalls during acceleration.

While these issues may not confirm that you have a tank of stale petrol on your hands, they could heavily point to that.

If you have a tank of stale petrol on your hands, you’ll need to get it drained and cleaned before you start fresh. Leave this to the service station pros if you’re not handy with cars. It also doesn’t hurt to get your entire car checked, especially if you have a carburettor.

Outside your tank

How long will it last?

If properly stored, petrol can last six months to a year outside your car. Always use containers that meet Australian fuel storage regulations and store them in a cool, well-ventilated place. Useful tip: metal cans last much longer than plastic. And always be aware of the risks involved with storing flammable substances.

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General Insurance

Insurance is issued by AAI Limited ABN 48 005 297 807 trading as Suncorp Insurance. Consider the Product Disclosure Statement before making a decision about this insurance. This advice has been prepared without taking into account your particular objectives, financial situations or needs, so you should consider whether it is appropriate for you before acting on it.