If you’re struggling to get your motor going just after you’ve filled the car, it could be that you have put the wrong fuel in the engine. Here’s what to do if this happens so that you can be on your way as quickly and safely as possible.
In cases where you have not already started the engine, which is obviously the better scenario, take the following steps:
1. Get a professional (e.g. a mechanic) to safely drain the wrong fuel
When they’ve checked and cleared the fuel lines and (ideally) the filter, you’re all set to put the right fuel in the tank.
2. Add the right fuel
Fill up properly, not just with a litre or two. For a small car, aim for a minimum of between 10 and 15 litres, for a larger model or van, you’ll need at least 20 litres, preferably more.
3. Turn the ignition on a few times without actually starting the car
Most modern petrol and diesel motors come with an electric fuel pump, in which case you will need to:
- Turn the ignition key or button to ON so that you illuminate the dashboard lights, without cranking the engine and leave it there for between five and 10 seconds before turning off again – do this three or four times. This allows the pump to prime the fuel system with the right fuel, while pushing any lingering fuel back to the tank or return line.
4. Next try to start up the engine
Press the start button or turn your key as you would normally. Don’t crank for more than a maximum of 10 seconds at a time. If your engine still isn’t starting up, give it 30 seconds before trying again.
Once it’s ticking over, let the engine run on idle for between two and five minutes. Don’t rev it up aggressively or drive off straight away, and keep an eye out for things like rough idling, warning lights, odd sounds or a strong smell of fuel.
5. Take a gentle test drive
For the first five or 10 minutes, drive slowly and gently without going at full throttle, high revs or at motorway speed.
If anything doesn’t feel right, stop and seek assistance straight away. That includes, for example, flashing warning lights, the engine cutting out, heavy misfiring or a persistent fuel odour. Pull over when you can do so safely and call a mechanic or roadside recovery service.
If you have driven on the wrong fuel
This situation is more complicated, and potentially particularly hazardous if you’ve put petrol in a diesel vehicle.
No professional should let you start your car again until they have:
- Drained the tank
- Flushed the fuel lines
- Checked or replaced the fuel filter
- Put in the right fuel
A stage-by-stage guide to next steps
- Check there’s enough of the right fuel in the tank aiming, as above, for up to 15 litres in a small car, more than 20 in larger models.
- Prime the system – in modern diesel models with an electric pump, turn the ignition on without starting the engine for 10 seconds, switch off then repeat between four and six times. This helps to push fuel and takes away air from things like the injectors.
- Try to start the engine – crank it for a maximum of 10 seconds. If it’s not working, wait 30 to 60 seconds before trying again. Diesel models may take a few more goes after a full draining, due to the air in the system.
- Once fired, keep the engine idling – don’t rev it up but let it idle for three to five minutes. It may sound a little rough for a few seconds.
- Check for warning lights and leaks – no fuel-system warning or engine lights should still be on, and you shouldn’t be able to smell raw fuel anywhere around the car, or see any drips under it.
- Go for a short, gentle drive – ideally near your home or the garage which has assisted; you should be fine if you can motor as normal for 10 or 15 minutes.
- Follow up (mostly for diesels) – change the fuel filter after 200 miles and discuss the fuel error when you next have a service so the system can be double-checked.
Things to avoid after putting the wrong fuel in your car
- Don’t continually crank for 20–30 seconds at once – you may drain the battery or overheat the starter.
- Don’t attempt to “clear it out by revving” a cold engine hard.
- Don’t loosen fuel pipes yourself to “let air out” – these systems run high pressure so doing this can be hazardous.
- Do nothing until you’re confident all the wrong fuel has been removed and replaced with the right stuff.
Keep Wrong Fuel Recovery’s number in your phone
At Wrong Fuel Recovery, we’re the specialists to call if you’ve put an incorrect fuel in your vehicle. We’ve got all the relevant certifications and are Which? Trusted Traders, so you can contact us with confidence.
Call 0800 193 1103 or 07538 889 922, and store our numbers in your phone. We’re here 24/7 UK-wide and one of our expert team can usually come out to you within the hour. We won’t leave you stranded, plus we offer a solution which is often more cost-effective than using a regular garage.
We’re here whenever you need us, always ready to resolve a potentially stressful situation.