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What should you do if you put the wrong fuel in your car?

We can all be absentminded, but when it comes to putting the wrong fuel in your car, a simple mistake can feel like a real disaster.

With that in mind, we’ve created this step-by-step guide to help put your mind at ease if you accidentally misfuel your car.

First and foremost, it’s important you don’t put the key in the ignition or switch on the engine. Here’s what you need to do next:

Your step-by-step guide

When you realise what you’ve done, don’t panic. Instead, follow the steps below, which will help you get back on the road safely:

  1. Put your car in neutral.
  2. Go back inside the petrol station and tell the attendant what’s happened.
  3. Ask someone to help you push your car to a parking spot nearby, so you’re not blocking a fuelling spot.
  4. If your car insurance or breakdown cover policy covers you for misfuelling, ring your provider and they’ll send someone to drain, flush and refuel your engine. It’s worth noting that, generally, the cost of replacement fuel will not be covered by your insurer.
  5. Once your engine’s been cleaned, and you have the right fuel in your tank, you can be on your way.

If you’ve not realised what you’ve done and have driven off, odds are your car will soon let you know by breaking down. If you have wrong fuel cover or breakdown cover, you should then ring your provider, and they’ll arrange for your car to be drained, flushed and refuelled as above. Bear in mind that fuel costs are usually not covered.

Will I have to pay to put it right?

Most car insurance and breakdown policies don’t include draining your engine. If that’s the case for you, you will have to pay to have this done, unless you’ve already added it to your policy as an extra.

If you’ve started your car and attempted to drive off, and you’re not covered for misfuelling, fixing the damage to your engine isn’t going to be cheap. 

Rias is one of the few insurers that include misfuelling cover as standard, which means we’ll pay to drain and flush your fuel tank as well as cover any damage to your engine if you accidentally put the wrong fuel into your car.[1] 

What does using the wrong fuel do?

If you add petrol to a diesel engine, it acts as a solvent. It mixes with the diesel present – even if it’s only a tiny amount – and increases friction, which can damage your pump and fuel lines. The more petrol that gets pumped through your engine, the more expensive it can be to put right, so don’t start your engine. In worst case scenarios, the damage can be so severe a completely new engine is needed.

The consequences of putting diesel in a petrol engine aren’t as bad because diesel won’t ignite without being compressed. This means that, aside from your car not starting and your spark plugs getting clogged up, no real damage should be done to your car’s engine. It’s actually quite unusual to make the mistake of putting diesel in a petrol engine, as the nozzles of diesel pumps are larger, so don’t fit as well. 

How can I prevent it from happening again?

Most misfuelling happens because people are rushing or distracted, so try to make sure you’re focused on the job at hand every time you go fill up on fuel.

You could leave reminder notes inside your car, or stuck to the fuel cap. If you have a diesel car, you might want to consider buying a cap that goes on your filler neck to stop petrol nozzles from fitting into it – but there’s no equivalent for petrol cars. 

If misfuelling does happen to you, you may find that having wrong fuel cover on your car insurance gives you the peace of mind you need to get back on the road quickly and safely.

Looking for car insurance that includes wrong fuel cover? Get a quote from Rias today.

[1] Replacement fuel costs are not covered.