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

So, you want to know what to do if you put the wrong fuel in your car. Well, don’t do what the editor of FirstCar did. He misfuelled his boss’s car, had the tank drained and cleaned without telling anyone at work, then left the receipt in the car for his manager to find…

Our editor may be a bit daft, but he’s not the only one. Someone misfuels their car roughly once every three and half minutes in the UK.

So don’t beat yourself up about it, and don’t panic.

So, what do I do if I have put the wrong fuel in the car?

  • Don’t start the engine!
  • Tell the petrol station what has happened, and find someone who can help you push the car to a safe place.
  • Got breakdown cover? Good. Call them to arrange for the tank to be drained, flushed and refuelled.
  • If you don’t have breakdown cover, find a local garage who can recover your car and drain and flush the tank. Check with your insurance company if you can claim back the cost.

What if I have already started the engine?

  • If you’ve put petrol in a diesel, then we have bad news. The petrol can damage the engine’s fuel pump and injectors, so costly repairs could be needed. If you have started the engine, turn it off as soon as you can. Have the tank drained and the system cleaned. Hopefully you stopped soon enough to prevent any damage.
  • Pumping diesel into a petrol is less serious, but still something you don’t want to make a habit of. It’s not as common as putting petrol in a diesel, as most diesel pumps won’t fit a petrol filler neck. Diesel is a heavier fuel, and the engine may simply fail to start. It will still need flushing out, though.

How much will it cost?

  • Check if you are insured against misfuelling. A fully comprehensive policy may treat this as accidental damage.
  • Breakdown insurance providers like the AA and RAC don’t usually include the cost of draining and cleaning a fuel tank in their standard cover. However, they will offer this as an extra service, with a lower price if you already have a breakdown policy. Expect to pay around £250-£300.
  • If you don’t have breakdown cover, a garage will be able to do the same job. They may charge you a bit more than a breakdown cover provider, though.
  • Drive any distance having misfuelled, and the bill could be up to £5000. So as soon as you realise your mistake, find a safe place to pull over and turn off the engine.

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