Will old petrol in tank damage engine?

Conrad3000

Hi all.

Last time I filled up was back in December 2020. I've not driven much due to the pandemic and I've still got about half a tank left.

The question basically is, does petrol (like oil) go 'off' after a certain amount of time, and if it does, will it damage the engine?

Thanks.

cymruchris

I wouldn't worry about it - just get on with using the car - and making sure everything else is in order - like the brakes and battery - if the car has been standing for a while - check the oil levels - you know all those things you're supposed to do regularly. Then fill up when you normally would. If your car was exceptionally old (and I mean ancient) there's a very small chance of rusty sludge at the bottom of the tank - so I wouldn't let the fuel drop to empty before refilling. 

cattom

that fuel will be fine. the only time petrol goes off is when the car has been stood for years. it goes 'stale'. you would know if your petrol was stale, because the engine wouldn't fire.

MoneyMate

I’ve wondered the same as I have a 5 Litre sealed can with Petrol that is about 4 years old, thought this link explains well.
https://www.rac.co.uk/drive/advice/know-how/does-fuel-go-off-old-fuel-and-fuel-storage-questions-answered/

rollingmoon

Conrad3000 said:

Hi all.

Last time I filled up was back in December 2020. I've not driven much due to the pandemic and I've still got about half a tank left.

The question basically is, does petrol (like oil) go 'off' after a certain amount of time, and if it does, will it damage the engine?

Thanks.

My experience has been that unleaded can go off in as little as six months. If it has, it will have a foul, sweet smell; it won't do any damage but the car will either run badly or not at all.

If it runs, I would brim the tank with fresh stuff and carry on - it won't do any harm. If not, then you'll need to drain the tank.