Can I use old petrol or diesel in my car?

With high petrol and diesel prices leaving people struggling to pay fuel bills, many drivers are turning attention to alternative sources, such as diesel and petrol sitting in the garage for the likes of garden machinery and generators - but is it safe to use fuel that's been stored for long periods of time?

Here we take a look at the feasibility of filling up with fuel from jerrycans that you have in the garage or garden shed.

*Disclaimer: It is the user's responsibility to ensure the diesel or petrol to be used is free from additives, contamination or other factors that could damage the vehicle's engine.

I have diesel stored in my garage or shed - can I use it in my car?

If the diesel you are intending to use in your car is less than six months old - and has not been stored in extreme hot or cold conditions - then it is likely that it will be safe to safely transfer the diesel fuel to power the diesel engine in your car or light van. However, if the fuel has been stored for more than six months - read on.

What if the diesel fuel in my can is more than six months old?

If the diesel fuel you have in your can is six to 12 months old, you could be risking serious and expensive damage to your vehicle's engine and fuel system.

As diesel ages, the fuel becomes thicker and a lot more sticky, this can combine to make it less efficient, with the resulting unburnt fuel clogging up diesel vehicle filters and injectors. This can lead to very expensive repair bills.

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How can I tell if the diesel fuel is too old to use?

There is no set way to tell, but if the fuel in the can appears thick or sticky compared with normal fuel, then you should not add it to your fuel tank.

If the fuel has been exposed to air, water, heat and light the safe storage limit will decrease rapidly - so only consider adding the diesel if it has been stored at around 20-degrees in a tightly sealed, purpose-made fuel container.

I have petrol stored for garden machinery - can I use it in my car?

Many of us have petrol stored in our garage or garden shed to power garden machinery such as lawn mowers, strimmers and hedge cutters - and because we're only just coming out of summer, it's more likely that any fuel you have stored will be relatively fresh.

Typically, petrol has a useful shelf-life of around six months - providing you have kept it stored away from daylight, at a constant-ish temperature (around 20-degrees is considered ideal) and in a purpose-made container that allows the fuel to breath but not be exposed to excessive amounts of air.

Provided the fuel is clear without sludge, and meets the above criteria, it's is likely to be okay to use in your vehicle - but you'll need to make the final decision yourself.

What if the petrol in my fuel can is more than six months old?

If the petrol is more than six months old or has been stored in a improper container - which is extremely dangerous and should be disposed of through safe official channels - then it could well be unsafe to put in your car.

Using old petrol can lead to making it difficult to start your car, and poor performance will also follow.

If the old petrol has suffered from oxidisation, you could risk clogging up sensitive internal working or your car's engine and landing yourself with a hefty repair bill.

How much fuel can I store at home?

In case you can grab fuel from a petrol station, don't think you can grab multiple cans and tanks to ensure you have a large stockpile. There are legal limits to what you can store. The limits are as follows:

  • Plastic container - storing up to 10-litres
  • Metal container - storing up to 20-litres
  • Demountable fuel tank - storing up to 30-litres

Call authorities if you have more fuel, or know of anyone who is, for advice.

*For general information only, contact your dealer or mechanic if in doubt.

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Author: Pete Barden:

Twitter: @pete_barden

Pete Barden is a qualified journalist who has written and produced for publications including The Sun (, New Statesman Media Group, Whatcar? ( Stuff Magazine (, Fastcar Magazine (, Maxim Magazine and UK broadcast stations within the Heart network (Formerly GCAP). Pete specialises in motoring and travel content, along with news and production roles. You can find out more about Pete Barden on LinkedIn.

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