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Misfuelling a Rental Car – What to do?

Renting a car is commonplace amongst the majority of us, particularly those that travel a lot, either for leisure or business, so driving another vehicle isn’t that uncommon to many of us. Unfortunately misfuelling a car is also rather popular with an estimated 150,000 motorists putting the wrong fuel in their car in 2016 in the UK alone. With an estimated 45 million licence holders in the UK, that’s a remarkable 1 in 300 of us put the wrong fuel in our cars in just one year!

misfuelling a rental car

Misfuelling you’re your own car is not only very inconvenient, but it can be very costs and the same applies to a rental car. It’s likely to lead to a hefty bill from the rental agent for repair costs (the extent of which will be determined by your actions, more on that later), plus the breakdown call out and of course the inconvenience to your holiday / travel plans.

Putting Diesel in a Petrol Rental Car?

Fortunately, as the majority of rental cars are petrol, it’s relatively rare as a diesel fuel nozzle at the pumps is larger in diameter than a petrol pump meaning it physically won’t fit in the filler neck of the car, your first warning sign that you have the wrong fuel. You’d have to be pretty determined to misfuel a petrol car with diesel at a regular petrol station! The same doesn’t apply however for a diesel car, its filler neck will easily accept the smaller nozzle of a petrol pump and this is where the danger lies. If you drive a petrol car at home and have rented a diesel, take extra care when refuelling as it could be a costly mistake.

Petrol and diesel engines are very different in the way in which they use the fuel in their systems and the chemical characteristics of either fuels is equally very different and both can cause major issues to the engine internals if run. It’s vital that you don’t try to drive the car once you’ve realised your mistake.

What to do if you Misfuel a Rental Car?

Much like misfuelling any car, we recommend the following steps;
  1. Do NOT start the engine
  2. Do NOT switch the ignition on
  3. Alert the fuel station staff who will be able to assist – move the car off the forecourt (remember, do not attempt to start the car), put the car in neutral and push the car to a safe place.
  4. Call the rental agent breakdown line
  5. Record how much of the wrong fuel you have dispensed from the fuel pump
  6. Estimate how much fuel was in the tank BEFORE you misfuelled
It’s vital that you do not start the engine as this will start the incorrect fuel entering the system. It’s also vital that you don NOT turn the ignition on either as many cars will start the fuel pump and prime the system for ignition which will again start the process of the fuel entering the system. Although in most circumstances the fuel can be pumped out of the system, it flushed through and the car refuelled, this process is likely to be an expensive mistake and it’s likely to be excluded from any car rental insurance policy.

Tips to Help Prevent Misfuelling a Rental Car

  1. Take care and time at the petrol pump, if in a different country familiar yourself with the fuel station before dispensing fuel. You're on holiday, what's the rush?
  2. Plan ahead using our ‘Car Hire: Nearest Petrol Station’ guide to avoid rushing when returning the car which could lead to misfuelling.
  3. Rent a petrol car – a diesel nozzle will not fit a petrol car, but don’t try to force it!
  4. Check the fuel filler cap, all rental cars will clearly state if petrol or diesel fuel is used.
  5. If renting abroad, familiarise yourself with the translation of ‘diesel’ and ‘unleaded’ and local names, ie in mainland Europe E-10 is unleaded, in France it’s ‘Sans-plomb’ There are often lots more options / grades of fuel at petrol stations in Europe than you might expect in the UK.
We all make mistakes in life, however hopefully the above information and tips will help you avoid making a car rental mistake that could prove very costly.

Kellie Hodge
Posted: November 16, 2017 by Kellie Hodge
About the Author -

Travel writer, customer service guru, Kellie knows the ins and outs of car rental and always happy to share her knowledge on our blog. Favourite country to visit: Spain.

Last updated: Thursday, November 16, 2017
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