Motor Insurance

Wrong fuel in your car? How to fix it and what it will cost

It’s a simple mistake—you grab the diesel fuel nozzle instead of the petrol one and start fuelling your car (or vice versa)... but just as you’re about to place the nozzle back into its gauge, you notice you’ve put the wrong fuel into your car. Panic sets in... what do you do now?!

Misfuelling is very common—in fact, in the UK someone puts the wrong fuel in their car every three and a half minutes. If you’re one of those unlucky individuals, here’s what you need to do to fix the situation, and how much it will cost.

If you’ve put in the wrong fuel, it’s vital you don't start the engine

Whether you’ve put diesel into petrol or petrol into a diesel, the one thing you must remember is don't start the engine. It’s going to cost you money to have the wrong fuel pumped out already but drive the car and you may do damage to several of the car’s parts and therefore be looking at larger repair costs! So, if you’ve misfuelled, here are the basic steps you should take:

  • 1) Go back inside the petrol station and tell the attendant what’s happened.
  • 2) Ask someone to help you push your car to a parking spot nearby, so you’re not blocking a fuelling spot.
  • 3) Put your car in neutral before you try to push it so the wheels can turn.
  • 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. If you're not covered by insurance then ring a local repair shop or one of the big breakdown chains for a non-member quote.

Once your engine has been cleaned, and you have the right fuel in your tank, you can be on your way. Next, we look at what it will cost to remove the wrong fuel from your car.

Cost to Fix Putting the Wrong Fuel in Your Car

Nimblefins spoke to the two major roadside recovery providers to get a price including VAT for having the wrong car fuel removed and the engine flushed out for a Ford Fiesta. These prices are nationwide and should apply whether you live in Leicester, Bournemouth, Liverpool or anywhere in between.

Wrong Fuel in Car Cost: Major roadside providers
AA Fuel Assist£249.99 for non-members across the UK
RAC Road Fuel Patrol£274.99 for non-members across the UK

For this price, both companies said they would remove the contaminated fuel and dispose of it safely, offer a fuel treatment to flush out the engine. AA mentioned they would include £10 of fresh correct fuel with clean additives within their price. AA also mentioned that this method has proven 99% successful in getting the car back on the road.

We also spoke to some independent garages in various locations to get an average cost of getting the fuel removed from a vehicle plus changing the fuel filter. Most garages said that a recovery service will need to tow the car to their garage for them to work on it, which would be an added cost:

Average Cost to Fix Putting Wrong Fuel in Your Car: Independent garages, by location
London£210.45
Manchester£175.51
Glasgow£160.43

How long does it take to flush the fuel from a car?

AA and RAC said that it would take approximate 60-90 minutes for their technician to arrive on site anywhere in the UK. From there, expect another hour or two to get you back on the road if all goes well.

I think I put the wrong fuel in my car, but I'm not sure

If you just finished filling up your car and as you slid into the driver's seat, suddenly had a thought that you may have put the wrong fuel in, what should you do? Check your petrol receipt. The receipt should list the cost per litre that you paid for fuel. Use that number (e.g., £1.24 per litre) and compare it to the listed prices on the pump. You'll be able to tell which fuel you used by matching up the prices. Also, the receipt might list the type of fuel you used.

Symptoms of putting the wrong fuel in a car

If you're driving down the road and your car starts to smoke, accelerates erratically (e.g., jerking) or makes a knocking sound, you may have put the wrong fuel in it. Pull over as soon as you can safely and call your emergency breakdown cover.

I’ve put petrol in my diesel car—what should I do?

We must stress, it’s vital that you remember not to start the engine. This type of misfuelling is a lot more common—putting petrol in a diesel car happens more often because the petrol fuel nozzles easily fits into modern diesel cars.

However, it's also the most damaging type of misfuelling because diesel engines use the diesel as lubricant, and driving a diesel with petrol means your engine will experience more friction and resulting wear and tear.

A mobile recovery service must be called immediately to remove all the petrol from your diesel car. Then you can start the car once it has been drained. If the car was driven or the engine was started then a more thorough flush of the car must be completed.

I’ve put diesel in my petrol car—what should I do?

As mentioned above, it is best not to start the vehicle. If you own a modern automatic car that doesn’t have the old-style key, and the car must be started in order to take it out of parking mode and unlock the steering, then a few moments with the engine running is less likely to cause any problems—just don't put it in gear and try to drive it.

If, however, the vehicle has been driven then it's highly recommended that a fuel cleaning additive is added once the contaminated fuel has been drained and the vehicle restarted, and for extra precaution, the fuel filter should be changed in the next couple of days. However, once the car has been drained, you should be back on the road again, but do expect to see a fair bit of smoke as the car rids itself of any residue diesel.

Additional costs to consider if you put in the wrong fuel in your car?

Most recovery providers will start by draining the fuel tank completely to remove the contaminated fuel, but more repairs may be required, and it’s always wise to change the fuel filter for extra peace of mind.

If your fuel filter needs changing

If the vehicle has been started, it is best to change the fuel filter as soon as you can after the wrong fuel has been used. When a vehicle has been started after having the wrong fuel put in the tank, a skilled technician will flush the correct fuel through the fuel delivery system before restarting.

Does insurance cover putting wrong fuel in car?

Many insurance providers will offer misfuelling cover as an added extra which you have to pay a premium for, and some will include it for free—for example LV=. It’s worth noting that, usually, the cost of replacement fuel will not be covered by your motor insurer.

However, if you decided to claim for misfuelling on your car insurance, you might find that you will be paying more, or just be breaking even, as you must consider your excess charge. With the average cost of misfuelling repairs, it might be wise to pay for the misfuelling drainage and repair yourself.

Have you put the wrong fuel in a rental car?

Putting the wrong fuel in a rental car is easy to do. If you're used to putting one type of fuel in your own car then it's natural to pick up the same type of fuel when filling up a rental—which is fine unless one is a petrol and the other a diesel, or vice versa!

If you put the wrong fuel in a rental car, the first thing to do is call the hire company's emergency breakdown phone number. And be sure not to drive the car until it's been fixed!

NimbleFins Editorial Team

Our team of writers has expertise in personal finance, travel, cars and pets.

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