Does fuel go off? Diesel and petrol expiry explained

Last updated March 03, 2023

After visiting your local petrol station, there’s a good chance you’ll use up your freshly-added fuel in the space of a few weeks.

However, there are certain circumstances in which fuel may sit in your car’s tank for a longer period. You might have stored your car in a garage whilst travelling abroad. If you’re a car collector, you may have several cars in storage that you don’t drive regularly. Perhaps you are planning to sell your car, but the vehicle has not been driven for a while.

If your car has been sitting idly for a while, you may be wondering, does fuel go off? In this guide, we will explain when you can expect fuel to deteriorate and spoil - and the differing shelf lives of petrol and diesel. We’ll also clarify whether expired fuel can damage a vehicle – and how you can prolong the lifespan of your fuel.

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Does fuel go off?

From the moment you put fuel into a container, you will only have a few months before its quality starts to deteriorate. If the fuel becomes contaminated in any way, its useful life will be even shorter. Petrol generally has a shelf-life of six months, if stored in a sealed container at 20 °C. When stored at 30 °C, this shelf-life is cut in half.

Can expired fuel damage a vehicle?

If your diesel or petrol has degraded in quality, but not yet expired, you may have difficultly starting your vehicle – and notice a decline in performance and efficiency when compared with new fuel. However, even if the fuel expiry date has passed, it shouldn’t cause permanent damage to your vehicle, especially if it is topped up with fresh petrol or diesel.

What is the shelf life of fuel?

Fuel generally has a shelf life of 3-6 months. Diesel can last up to a year before you come close to its expiry date. However, organic-based ethanol can lose combustibility in just 1-3 months.

How do you know when fuel has expired?

You will be able to tell from the colour and smell of the fuel. Bad fuel will usually be darker and muddier, with a sourer smell than fresh fuel.

How do I know how old fuel is?

There is no specific way to check the age of fuel, so simply take a good look at it to check for signs of spoiling if you are concerned it has expired.

Can you fill up a fuel container at the petrol station?

Yes, you should be able to take a plastic container or a metal jerry can to your local petrol station to fill up. Some stations might have specific rules around the styles and sizes of container that are permitted, so ask ahead if you’re not sure. When filling your container, place it on the ground to avoid potential spillages - and make sure it is properly secured in your vehicle.

Read our guide to finding the cheapest petrol and diesel prices to help you seek out the best fuel prices in your area.

What container should you use to store fuel?

If you want to keep fuel at home, use either a plastic portable container or a metal jerry can with a tight-fitting cap. Make sure your chosen container is sold specifically for use with petrol or diesel.

Is it legal to store fuel at home?

Yes, it is legal to store fuel at home, but you can only keep a certain amount at any given time.

How much petrol can I store at home?

When it comes to petrol, if you are using a plastic container, you can store up to 10 litres at any given time. If you use a metal container, you may store up to 20 litres - and in a demountable fuel tank, you may store up to 30 litres.

If you intend to keep any more than 30 litres of petrol, you’ll need to write to the Petroleum Enforcement Authority (PEA), providing your name and address as the occupier of the storage place (or the address where the petrol is stored). The maximum quantity of petrol you can store at your home, after advising the PEA is 275 litres.

How much diesel can I store at home?

When it comes to storing diesel, there aren’t any specific requirements or limitations.

Is it safe to store fuel at home?

Yes, it is safe to store fuel at home, providing you do so under the right conditions.

Where should I store fuel?

When storing petrol, it’s best to keep it in a secure outbuilding (such as a garage or shed) that is well ventilated and away from any sources of ignition. The space should be as cool as possible - and well out of the reach of children.

Using fuel stabiliser

Fuel stabilisers are intended to extend the fuel expiry date, for both petrol and diesel. When using a stabiliser, make sure it’s suitable for the fuel you’re using. Follow any instructions on the label.