Put the wrong fuel in your car?
Follow these steps to ensure you get the right help available to get your vehicle back on the road.

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

While misfuelling may feel like something that could never happen to you, over 100,000 Brits report it to the AA each year.

As it is such a common occurrence and easily done, it’s worth knowing what damage it can do to your vehicle and whether you can claim for it on your insurance.

In This Guide:

What to do if you put petrol in a diesel car

When petrol runs through a diesel engine it causes significant damage to many components. This damage can cost thousands to repair and in severe cases can result in complete engine failure.

The most commonly affected components are:

  • The fuel lines - When petrol enters the fuel lines of a diesel car it will coat them and head towards the engine. The fuel lines will need flushing and in the worst cases replacing.
  • The filter - The filter prevents contamination to the engine. If it comes into contact with petrol it will need replacing.
  • The fuel pump - Running petrol through a diesel fuel pump results in high amounts of friction which can lead to metal fragments being dislodged into the fuel system.
  • Fuel injectors - If any metal fragments find their way into the fuel injectors, they can block the small holes which will ruin the whole system. This will result in the injectors needing to be replaced, which will cost thousands of pounds.

Petrol can ruin a diesel engine very quickly, so the speed at which you react to misfuelling can mean the difference between hundreds and thousands in terms of damage. If you notice any engine irregularity, you should pull over and contact your breakdown provider.

As it is not always immediately apparent that you have used the wrong fuel, it is advisable that you have misfuelling cover on your car insurance policy should the worst happen.

What to do if you put diesel in a petrol car

While not as severe as putting petrol into a diesel car, this type of misfuelling can still do damage to your engine. In most cases it will cause the engine to smoke or cut out completely if continued to be in use.

Once you notice the engine start to act irregularly, you should pull over and contact your breakdown provider for further assistance.

Is wrong fuel cover included in my car insurance?

Most insurance providers will not cover misfuelling or wrong fuel cover as part of a standard policy. Often, if the provider offers misfuelling cover it will come as an optional extra on your breakdown cover policy.

When you compare car insurance or breakdown cover, it’s worth noting the terms and conditions for misfuelling cover and what you will be protected against. Some providers will only cover the cost of cleaning and draining while others will cover you for the cost of all repairs, so it’s important to check that you have the best cover before committing.

How to avoid misfuelling

Even the most experienced drivers can accidently put the wrong fuel in their car due to lack of care and due diligence. It’s important to always double check at the pumping station and keep abreast of new fueling labels on pumps. Petrol cars should use E5 or ‘leaded/unleaded’, while diesel drivers should use B7 or ‘diesel’.

New labels are designed to tell you exactly what is going in your car and what renewable fuel source is being used. The shape of the label indicates the fuel type - a circle is for petrol and a square for diesel.

The letters indicate the renewable fuel source - E for ethanol and B for biodiesel. The numbers tell you what percentage is made up of renewable fuel.

Compare misfuelling cover

Misfuelling can be a grey area with car insurance, with some providers only covering cleaning and not damage, while some don’t cover it at all. Money Expert can help you find cheap caar insurance with misfuelling cover, and ensure you know what will be covered before committing.

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