Log in or register
My AA Account

Sign in to see your cover and request assistance online

Log in

Don’t have a My AA account?

You’ll need your policy or membership number

Create an account

Your Finances

Loans | Savings | Credit Cards

Your Driving Lessons

Book a lesson


Put the wrong fuel in?

Diesel in a petrol car, or petrol in a diesel car?


Don't turn on the ignition or start the car – call us straight away on 0800 072 7420
AA Fuel Assist is available to Members and non-Members
On average, someone puts diesel in a petrol car or petrol in a diesel car every three and a half minutes – so you’re far from alone. What matters is what you do next.


Don’t turn the key!

  • Call AA Fuel Assist straight away on 0800 072 7420
  • We’ll come out to you, remove the contaminated fuel and replace it with clean fuel
  • Calling us before you turn the key means that you can avoid possibly costly repairs to your fuel system

Too late?

  • If you only noticed your mistake when your car ground to a halt, we should still be able to help
  • Assuming the problem has been discovered fairly quickly, Fuel Assist can drain, flush and refill your tank at the side of the road
  • Call us on 0800 072 7420

Wrong fuel advice

Petrol in diesel car

This is the more common call out we get as petrol nozzles fit easily into most modern diesel filter necks. It’s also the more serious of the two mistakes.

Diesel acts as a lubricant, helping the fuel pump to do its job. If petrol’s mixed with diesel it has the opposite effect, acting like a solvent. The more it’s pumped through your fuel system, the more damage it will do. It can even result in you needing a new engine.

Common rail (or HDi) diesel engines are particularly susceptible to damage from misfuelling. You could be looking at new fuel pumps, injectors, pipes, filters and fuel tank.

Diesel in petrol car

This is far less common as the diesel nozzle is physically larger than the petrol filler neck on most cars.

Around a third of the calls to AA Fuel Assist are for diesel in petrol, which can cause serious damage – particularly to direct injection (GDI) petrol engines.

Prevent misfuelling

If you’re used to driving several different cars, or fill up at loads of different petrol stations, here are a few tips to help you avoid the cost and hassle of misfuelling.

  • Don’t rely on the colour of the hose or nozzle. Check the label on the pump trigger and the fuel grade indicator on the pump
  • While you’re getting used to a new car, or a hire car, leave yourself reminders that it’s different to your usual car
  • Keep your concentration at the fuel pump. It’s not a good time to get distracted
  • Try not to refuel when you’re in a hurry or stressed
  • If you drive a diesel car and are worried about misfuelling, you can buy a device that fits into your filler neck to prevent you inserting the narrower petrol nozzle

AA Fuel Assist

Our trained technicians can retrieve the fuel from your vehicle at the roadside, restart the engine and get you back on you way, in 99% of cases