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Are you insured for misfuelling?

What to do if you put the wrong fuel in your car

Man holding a petrol pump to his face looking very angry

Nooooo! Your heart sinks. You've just realised you've put petrol in your diesel car. What on earth do you do now?

What is misfuelling?

Misfuelling is simply putting the wrong type of fuel in your fuel tank. So if you drive a diesel car and you full it up with unleaded – that's misfuelling.

You might be thinking that it's just not possible to put the wrong fuel in your car these days. The nozzles are different shapes aren't they?

Well, it's certainly more difficult, but not impossible to put diesel in a petrol car. The nozzle on a diesel pump is bigger and therefore won't fit in the neck of a petrol tank smoothly. However, it's much easier to accidentally put petrol in a diesel car.

The petrol nozzle is smaller and fits into the diesel tank easily. It's only when you realise you're holding a green pump not a black one that the penny drops.

And it's not uncommon. The RAC estimate around 150,000 people a year put the wrong type of fuel in their car. Sometimes with very expensive consequences.

What can misfuelling do to your car?

Putting petrol in a diesel car causes all sorts of problems. Diesel acts as a lubricant, making the engine and its components run smoothly.

Petrol acts as a solvent, so it prevents the lubricating action of the diesel. This means that the fuel pump runs without lubrication, so its components rub together, grinding off small fragments of metal called 'swarf'.

These fragments can travel towards the fuel injectors and clog up the holes in the injectors. This stops the fuel reaching the engine and eventually the car judders to a halt.

On the way to the fuel injectors, the petrol can also corrode the seals on the fuel lines that carry the fuel from the tank to the engine and can contaminate the fuel filter.

If the petrol reaches the fuel injectors and they need replacing, together with the fuel pump, fuel lines and fuel filter, it can become a very expensive repair job.

Five golden rules if you misfuel

Don't drive off. If you realise your mistake at the petrol station, don't start the engine. This begins the sequence of events that cause maximum damage to your engine.

Do inform the garage attendant. Explain what's happened – it's quite likely they have dealt with this problem before.

Do get help to push your car to a safe place where it can be drained. Some breakdown organisations will drain your fuel tank on the petrol forecourt.

Do call your car insurance provider. They may provide cover that pays for the cost of draining your fuel tank or repairing your engine. Call them first as they may have a procedure they need you to follow to get the repairs sorted out.

Don't just keep going. If you've already left the petrol station before you realise your mistake, don't keep going until the car breaks down. Pull over somewhere safe and call your insurance provider or a breakdown organisation.

Are you covered by your insurance?

You can find out if you're covered by your car insurance by reading the policy details. Misfuelling will probably be mentioned under accidental damage.

If your insurance policy doesn't cover misfuelling, it should have an exclusion clause that specifically excludes making a claim for misfuelling.

LV= provide cover not only for draining and flushing your fuel tank, but also for damage to your car engine caused by the wrong fuel.

You can find out if you're covered by your car insurance by reading the policy details.

Ways to prevent misfuelling

Accidents happen but there are a few things you can do to make sure you don't put the wrong fuel in your car:

  • Put a sticker with the name of the fuel inside the fuel cap
  • Always read the label on the pump
  • Do a double check to make sure the labels on the fuel cap and the pump match
  • If you change between cars with different fuel types consider installing a device to prevent misfuelling
  • Try to eliminate distractions when you get to the pump

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