What to do if you fill your car up with the wrong fuel

Fixing your car after misfuelling

Filling your car up with the wrong fuel is easier to do than you may first think, especially putting petrol into a diesel vehicle. Read on to find out what to do if this happens to you.

Simple Steps to Remember:

There are a few simple steps to remember if you misfuel your vehicle:

1. Don’t start the vehicle as this could cause permanent damage.

(If you have already turned on your vehicle before realising, turn off the engine as soon as possible, the less fuel that is pumped around the engine the better).

2. Put your car into neutral and push it to a safe place.

3. Call your breakdown company, they will need to drain your vehicle before taking it to a local service centre.

It’s important to remember that circumstances change dependent on what fuel you put into your car. Take a look below to discover what happens when you put the wrong fuel in your vehicle.

What happens if you put Petrol into a Diesel car?
This is the most common way people misfuel their vehicles as petrol nozzles fit easily into diesel cars. It’s also the most damaging for your vehicle. This is because diesel vehicles use fuel as a lubricant, preventing wear and tear and ensuring that the fuel pump and engine can do their job. Petrol has an opposite effect on the engine and its parts, it causes friction between the components. The more petrol that is pumped around the engine, the more damage that is caused.

If you put petrol into a diesel vehicle and do not realise your mistake before driving off, there are a few things you might notice:

  • Your vehicle does not start or might struggle to start
  • The engine warning light comes on your dashboard
  • Smoke starts coming out of your exhaust
  • Acceleration is slow
  • A knocking noise when accelerating

What happens if you put Diesel into a Petrol car?

This is not a very common mistake, as the nozzle for diesel is usually bigger than petrol filler necks. Luckily, it also causes considerably less damage.

It’s easy to tell whether you’ve put diesel into a petrol vehicle because your vehicle will fail to start or at least cut out very quickly. The diesel will cover the spark plugs that ignite the engine, so the car won’t be able to start.

Putting E10 into a non-compatible vehicle:
E10 was introduced across the UK in 2021 as part of an initiative to reduce carbon emissions. The majority of vehicles are compatible with E10, however, for some older vehicles, it can cause issues. If you accidentally misfuel your vehicle with E10, it can cause some damage to metals, plastics and seals, though the effect won’t be instant, this will only occur over a longer period.

To resolve this, you should fill up with compatible fuel as soon as you can as this will reduce the amount of E10 in your vehicle’s system.

Is it possible to misfuel an electric car?

No, it is not possible to ‘misfuel’ your electric vehicle. Whilst, there are two options when it comes to charging your vehicle; AC and DC, each option has a different adapter and therefore it is not possible to get the two confused.

AC stands for Alternating Current/Power - this is used for charging vehicles at various speeds.

DC stands for Direct Current/Power – this is used for fasting charging vehicles.

EVs convert AC power (available on the power grid) to DC power.