What To Do If You Put The Wrong Fuel In Your Car?

Putting the wrong fuel in your car is a mistake that we all think will never happen to us until it happens. This is often know as misfuelling and usually happens when the driver is in a rush or get distracted in the middle of re-fuelling.

The worst is if you’re borrowing a car that you’re unfamiliar with or a courtesy car. Because filling up your car is a repetitive action that you’ve done hundreds of times its easy for your mind to wander so you’re not fully concentrating.

Luckily, its almost impossible to accidentally put diesel into a petrol engine car because the diesel nozzle is too wide to fit into the petrol entrance. However, this means that the broader diesel pump provides sufficient access for the petrol nozzle, and petrol in a diesel car can do a large amount of harm to your vehicle.

If you do accidentally misfuel then it’s important you actually realise before you drive off.

Why Is This So Harmful?

The main function of diesel is to power the vehicle, but it also acts as lubrication to keep the fuel pump and its internal components functioning efficiently. Petrol does the opposite and turns into a solvent when its combined with diesel.

So when they’re combined it will cause the friction between the parts to increase which will lead to damage. Because of the fall in lubrication, small fragments of metal are formed from the components rubbing together and these fragments enter the fuel system. Most fuel tanks have a filter which will catch most of the fragments but if they make it into the injector this can result in expensive damage.

The Result

The later you realise you’re mistake the more costly it will tend to be. If you fill your diesel car with petrol and start the engine then you’ll need to have the engine flushed and the petrol completely pumped out of the fuel tank. Depending on the extent of the damage you may need to have replacement parts fitted for the fuel pump, pipework, injectors etc.

What To Do?

The most important thing to do is make sure that you don’t start the engine. Even starting the ignition will cause activate the fuel pump and damage will begin so it’s best to not even put the key in the be safe.

The advancement in technology actually can cause more problems, because pre-ignition systems start fuel pumps in new diesel models as soon as you unlock the doors. This is so the engine can have more time to warm up but also means that it can cause harm to your engine quicker if you’ve used the wrong fuel.

You should then get assistance from the gas station to push your car into a safe place out of the way so other vehicles can continue to fill up. You then need to call your breakdown cover provider who will then be able to help, where they will usually drain, flush and refuel your car allowing you to get back on the road.

If you have unfortunately driven off with the wrong fuel, then you’ll quickly realise your mistake as your car will come to a stop. You will still call your breakdown cover and treat it the same as a normal breakdown and they will come and follow the same steps of draining, flushing and refuelling your engine.

Although you can tell that you’ve used the wrong fuel by simply looking at your receipt, the other signs include

  • Difficulty in starting the engine
  • Your exhaust smoke is smokier than usual when driving
  • The engine may not stop once you’ve started it
  • Instant loss of power
  • Losing complete power
  • Extremely loud noise from the engine
  • Is misfuelling covered under insurance and breakdown cover?

Most standard breakdown cover policies will cover taking you to the nearest garage or to your home address but the process of draining and flushing the tank may incur added costs or be an add-on to the standard cover. You can alternatively find a local garage that provide this service.

It varies from insurer to insurer whether misfuelling is covered as standard so you may be covered for the accidental damage but the damage caused to the engine may not be covered so will have to be paid out of your own pocket.

The best thing you can do is check you current breakdown cover policy small print to see how covered you will be against this.

If you don’t have breakdown cover then there are many providers that specialize in breakdowns specifically for misfuelling. This will be significantly more costly than if you have breakdown cover especially depending on the area that you’re in and if there are companies within range of you. You’ll often have to spend more if you’re in a remote location as they’ll be paid on an hourly rate which includes the travel time to get to your location.

How To Prevent Mis-fuelling

The best way to prevent this from happening is to pay attention whilst refuelling focusing on the pump that you’re selecting. In only takes a minute or two to re-fuel so put your phone away and give it your undivided attention.

Alternatively you can fit a diesel fuel cap to the fuel neck which stops petrol nozzles from fitting into the wrong fuel tanks that they’re not designed for.

A cheaper way is to purchase blank stickers and write diesel on them that you then place on the fuel cap and the fuel filler flap which will reduce the chances of filing up with the wrong fuel.

Driving an electric car will also prevent this from happening as there will be no way to accidentally introduce the wrong fuel into the engine.

If you’re using a different car or you’ve just bought a new one with a different fuel type then you should leave prompts and reminders in the car to lower the risk of you selecting the wrong fuel pump.

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