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

We’ve all been there. You’re rushing around with shed loads to do and need to quickly stop off for petrol before you move on to the next thing on your to-do list. It’s the last thing on your mind and - before you’ve checked, brain on autopilot - you discover an annoyingly inconvenient error. You’ve put the wrong fuel in your car.

The panic hits you as you wonder what on earth to do next, and most importantly is putting the wrong fuel in your car covered by car insurance?

Here are a few tips to help solve the problem.

What happens when you put petrol in a diesel engine?

As well as powering the car, diesel acts as a lubrication that keeps the fuel pump and other components running. Petrol, on the other hand, acts as a solvent when mixed with diesel, and so has the opposite effect. Adding petrol to a diesel engine increases friction between parts, causing damage to the fuel lines and pump. If you drive away or even start the car with petrol in the mix, you could cause expensive damage to the engine.

Diesel pump nozzles tend to be larger than most petrol fuel necks, so misfuelling in a petrol car doesn’t happen as much.

What to do about the issue

If you’ve realised your mistake before starting the engine (which will make things easier), here’s what you need to do:

If you have breakdown cover, give them a call. They should be able to drain, flush and refuel your car. Draining the fuel should take between 20 and 60 minutes.

If you aren’t so lucky and you drive off with the wrong fuel, you’ll soon realise what’s happened when the car grinds to a halt. In this case, you’ll need to talk to your insurer, and it is generally treated as a regular breakdown.

Is putting the wrong fuel in a car covered by insurance?

This will vary depending on your insurer. However, generally, if you put the wrong fuel in your car and damage the engine, you are likely to be covered. But if you break down as a result, you would need breakdown cover in place to fix it for you. Some insurers do claim to not cover misfuelling at all, so make sure you’ve carefully read your policy.

How to avoid making the same mistake again

As well as being a little more vigilant at the petrol station, there are a couple of things you can do to avoid putting the wrong fuel in your car.

The most common solution is to fit a diesel fuel cap to your fuel neck. This cap stops petrol nozzles from fitting into fuel tanks they’re not meant for. The useful little caps are designed to fit into specific makes and models, so make sure you buy the right one for your car. They can be anywhere between £15 and £30 from places like Amazon.com .