What to do when you put petrol in your diesel vehicle

Driving comes with many risks, but the simple task of fuelling up isn’t risk-free either. If you’ve ever put petrol in your diesel vehicle, you’re not alone in making that mistake. According to the Royal Automobile Association of South Australia (RAA), 7500 misfuelling events, of people doing just that, occur every year nationally. This mistake could cost you your engine if you don’t deal with it properly, however, there are actions you can take to minimise the cost of repairs.

What happens?

By mixing petrol with diesel fuel that’s already in your tank, you’ll create a solvent-like mixture. If you start your engine, this will immediately cause damage to your fuel system and, if not dealt with quickly, will result in needing a new engine, fuel pumps, filters, injectors and fuel tank. Modern diesel vehicles equipped with common-rail systems in their engines are particularly susceptible to this kind of damage.


What should you do?

The good news is that this problem can be solved with less cost if you realise your mistake before getting back into your vehicle.


Don’t press the start button or turn the key and the damage will be minimised.

You will have to move your vehicle out of the way of others wanting to use the fuel bowser – shift your vehicle in neutral, release the hand brake and push it out of the way to a safe parking spot. Then, call your roadside assistance provider because you are going to need a professional to drain the contaminated fuel from your fuel tank.

However if you do drive away from the service station with the incorrect fuel in your tank, you will notice changes very quickly. The engine will begin to make some horrible sounds and if you do keep driving, your vehicle will grind to a halt. Stop as soon as you can and call the professionals.


 How to prevent this from happening

You are more likely to make a mistake like this with unfamiliar vehicles. Borrowing or hiring a vehicle overseas, especially when you don’t know the language, can add to the confusion. Make sure to ask what fuel the vehicle needs before taking off.

If you forget or are unsure, there is almost always a sign on the inside of the filler cap that says “Diesel only”, “Petrol only” or “Premium unleaded only”.

Don’t just rely on the colours of the pumps as this can be deceiving. The colours may be different from what you are used to, or the colours may have changed without you knowing. Make sure to read the labels on the bowser to see what each one is for. If you’re still unsure, don’t just guess – ask the service attendant for help.

Ultimately, you need to take all the necessary steps to avoid putting the wrong fuel in your car. This error, if handled incorrectly, can cost you a lot of money and may ruin your vehicle. Prevention is essential, but if you do make this mistake, follow one simple rule – don’t start the engine. If you do this, your vehicle should ideally be back to normal after resolving the issue.