Filled up with the wrong fuel

Put petrol in a diesel...?

Don't start your car, call AA Fuel Assist on

0800 072 7420
or 0121 535 7479

Wrong fuel?
Diesel and petrol cars

We cover petrol and diesel cases

...or diesel in a petrol car?

Approximately 150,000 motorists every year put the wrong fuel in their vehicle. This might be because someone is not used to the vehicle or is simply distracted while filling up.

Stop the engine as soon as it is safe to and call 0800 072 7420 or 0121 535 7479.

The AA's dedicated technicians will:

  • assist cars, vans and motorcycles
  • remove the fuel out of the system 

Our main aim is to get you back on the road within two hours.

What to do next

Do not try to start your car or turn on switch the ignition as this will cause the fuel to be pumped towards the engine.

We have a team of trained Fuel Assist technicians who can retrieve the incorrect fuel from your vehicle at the roadside, restart the engine and get you back on you way 99% of the time.

Lines are open 24 hours a day, seven days a week. The Fuel Assist service will be provided on an appointment basis between 6am and 11pm, seven days a week.
Fuel AssistSM is a registered Service Mark.
We will attend any vehicle providing the Fuel Assist van has enough capacity in its tank.

Caring for the environment
Petrol or diesel

Environmental note: we will recycle the contaminated petrol and diesel through an environment-friendly disposal process.

Petrol or diesel advice

Starting the engine will circulate the contaminated fuel and increase the risk of damage.

If you're on a petrol station forecourt, put your car into neutral and get help to push your vehicle to a safe place.

If you have driven a short distance after misfuelling, safely and legally park the vehicle, turn off the engine and call us.

If the misfuelling has gone unnoticed, the car will eventually stop.

For AA Fuel Assist – call 0800 072 7420 or 0121 535 7479.

The effect of petrol in a diesel vehicle can be very expensive – manufacturers often recommend change of parts (as high as £5,000+) and garages often charge £300+ for a fuel drain. 

Find out what happens if you add the wrong fuel to your car.

Petrol in a diesel

This is the most common wrong fuel occurrence. Approximately 70% of calls for assistance with misfuelling to the AA are diesel vehicles having been filled with petrol.

Petrol contamination of a diesel fuel system can cause the lubricating qualities of the diesel fuel to be ‘washed out’ and starve the moving parts of the injection system of lubricant. Depending on how long the diesel vehicle has been run on the petrol will determine any potential consequential damage. Best practice is not to start the engine as this will reduce the risk of the petrol washing the lubrication out.

On the forecourt

If you’ve just started putting petrol in a diesel and realised mid-way, stop. Take a note of how much you’ve put in. Talk to the staff at the filling station, pay for your fuel, then put your vehicle in neutral and push to a safe place until you get assistance.

Finished filling the tank

If you’ve filled up with petrol and paid but you’re still on the garage forecourt, don’t start the car. Go back into the filling station and explain what has happened. Put the gears in neutral and push the car to a safe place and wait for assistance.

If you've started the car, stop as soon as you can and when it's safe to do so.

Signs of petrol in a diesel

If you suspect you have put the wrong fuel in, tell-tale signs may be:

  • a smoky exhaust
  • engine noisy under load
  • difficulty starting the car especially when the engine is warm

The car might even eventually stop. Just call 0800 072 7420 or 0121 535 7479.

Diesel in a petrol car

This is much harder to do and is less common to the AA than petrol in a diesel vehicle.

Approximately 30% of calls to the AA for misfuelling are where the driver has put diesel in a petrol car. This is because the diesel trigger nozzle tends to be bigger and often won't fit a petrol car.

Diesel contamination of a petrol fuel system will cause the engine to smoke excessively, misfire and cause difficulty starting. The petrol fuel filter will become contaminated with the oil base of the diesel fuel. Spark plugs will also become oiled and contaminated causing the vehicle to run rough, cut out and not restart. On some petrol vehicles the emissions controls can also become contaminated especially if the vehicle has been started and driven.

On the forecourt

If you’ve just started putting diesel in a petrol car and realised mid-way, stop. Take a note of how much you’ve put in. Tell the staff at the filling station and pay for your fuel. Put the gears in neutral, move your vehicle to a safe place and wait for assistance.

Filled up with diesel

If you've filled up with diesel and paid but you're still on the garage forecourt, don't start the car. Instead, go back into the filling station and explain what has happened. Again, put the gears in neutral, move your vehicle to a safe place and wait for assistance.

If you’ve started the car, stop as soon as you can and when it's safe to do so.

Tell-tale signs of the wrong fuel may be:

  • an excessively smoking exhaust
  • lack of power
  • engine misfiring
  • engine cut out and won't restart

Call us on 0800 072 7420 or 0121 535 7479 and we can advise.

Fuel Assist terms and conditions

Please read the current terms and conditions for the AA Fuel Assist service.

To view PDFs you'll need Adobe® Reader®

Download it

AA Fuel Assist

Filling up with the wrong fuel

Putting the wrong fuel in your car?

What do I do if I have put the wrong fuel in my vehicle?

Just call 0800 072 7420 or 0121 535 7479. Do not try to start your car or turn on switch the ignition as this will cause the fuel to be pumped towards the engine. The AA has a team of trained Fuel Assist Technicians who can remove the incorrect fuel from your vehicle at the roadside and restart the engine. We get you back on the road in 99% of cases.

What happens if I have started my car or driven it?

If you have started the vehicle, stop before the car cuts out and contact our dedicated team who will be able to advise the next course of action. Just call 0800 072 7420 or 0121 535 7479.

What does AA Fuel Assist do?

On arrival our technicians will ensure your safety, secure the area because there is a fire risk to this activity and get to work retrieving the incorrect fuel from the fuel system in an approved and safe manner. We aim to get you back on the road within two hours.

What sets the AA apart from the rest?

The AA has been helping people by the roadside for well over a century. As with all our patrol force, our Technicians are well trained. They all hold a Safety Pass Alliance (SPA) Passport for dealing with fuel on Petrol forecourts, ADR class 3 for the transporting of flammable liquids. We operate to an approved and audited safe system of work. Your safety and the safety of others are our priority.

Back to top
AA member card

Up to 15% off for AA members

If you hold another AA product such as breakdown cover or insurance, you’ll have been issued with an AA card, which gives you between 5% and 15% off today*.

If you've been with the AA for a long time, you may qualify for the higher discount.

Have your AA card to hand when you call us and quote the 16-digit number when asked to claim your discount.

For AA Fuel Assist – call 0800 072 7420 or 0121 535 7479.

* Up to 15% discount for AA members who have held AA membership for one year or more. AA members in their first year and AA customers who qualify for AA Rewards receive a 5% discount. These discounts can be withdrawn or varied at any time.