I put the wrong fuel in my car, am I covered?

Putting fuel into vehicle

October 14, 2021

Filling up your car with the wrong type of fuel is easily done, but isn’t so easily remedied.

According to the RAC, approximately 150,000 absent-minded Brits pump the wrong fuel into their cars every single year (that’s over 400 of us per day!), so you are not alone if you are experiencing this.

If you are, at this very moment, sitting in your car at a fuel station after putting the wrong type of fuel in your car, DO NOT put your key in the ignition and start the engine! Instead, take a breath and calmly read the advice below.

Here’s what you should do after putting the wrong fuel in your car, how much it can cost to remedy and whether or not you’re covered.

What happens if you put the wrong fuel in your car?

The good news: Whilst you can easily put the wrong petrol in car (i.e. a premium brand of petrol instead of the standard unleaded), putting diesel in a petrol car is usually physically challenging. This is because a diesel nozzle is usually too large to easily be inserted into the smaller opening of a petrol tank.

The bad news: Sadly, a petrol nozzle will easily glide into the opening of a wider diesel tank opening and, we’re not going to sugarcoat this, but putting petrol into a diesel car can be catastrophic for your engine and, indeed, your pocket.

So what actually happens when you put petrol into a diesel car and what should you do?

  • Diesel fuel pumps fully rely on the lubrication supplied by diesel to work efficiently and effectively and putting petrol into a diesel car will significantly reduce this required lubrication. Diesel is like WD-40 for your car engine.
  • Without this lubrication, metal-on-metal contact occurs in the fuel pump resulting in small metal fragments entering the fuel injection system and causing potentially catastrophic damage to your car’s fuel pump and engine.
  • What happens next will depend on how much petrol you’ve mixed with diesel and whether you start your car or worse still, drive it.
  • If you accidentally put a very small amount of petrol into a diesel tank (no more than 5%) then you can top up the remaining 95% of your fuel tank with diesel and this should sufficiently dilute the potentially devastating effects of the petrol. If you’re not sure how much petrol you’ve put in or what 5% capacity of your fuel tank is, you should err on the side of caution and arrange for your tank to be professionally emptied before you use your car.
  • If you’re lucky enough to realise your refueling error before starting your car, then you must not put the key in the ignition or start the engine.
  • If you put petrol in a diesel car by mistake and drive it, as soon as you realise your error, you should immediately turn the ignition off and put your car in neutral. Starting your car alone will kickstart the whole lack of lubrication process outlined above and potentially cause extensive damage. What’s more, actually driving your car could cost you hundreds of pounds or, in some cases, thousands of pounds in repairs - recovery of a vehicle, a fuel drain and fuel pipe clean doesn’t come cheap!
  • If your car is in the way at a fuel station or on a main road, do not start the car to move it. Instead, see if you can find a strong, good-spirited passerby to help you push your car to a safer location.
  • If your accidental damage insurance includes cover for misfuelling, then contact your insurer to arrange for roadside assistance. They will have a 24/7 helpline - if you haven’t got this to hand, Google it. If you’re not sure if you’re covered, contact them anyway to check as you could save yourself a lot of money.
  • If you want immediate roadside assistance, you can try calling the AA’s mobile fuel draining service, called ‘fuel assist’ on 0808 274 1946. In 2011, the AA was charging £209.34 for AA Members and £246.29 for non-members so check the fee when you call. You can also try calling the RAC’s Fuel Drain Patrol on: 0330 332 8456 to see if they can help. The RAC’s service costs £274.99 for non-members and RAC members get £50 off.
  • Alternatively, if you don’t mind waiting and it works out cheaper, you should contact a local vehicle recovery service and arrange for your vehicle to be taken to a local garage who should have the tools and capability of professionally draining the tank and refilling it and, if necessary, flushing your fuel pipes and fitting new filters.

Is wrong fuel covered by car insurance?

Most standard car insurance policies do not provide cover for wrong fuel recovery, drainage and/or repairs.

In fact, a Defaqto survey of 363 fully comp car insurance policies revealed that only 8% of insurers provide misfuelling cover as part of their comprehensive policies.

The same survey revealed that only 4% of insurers will provide misfuelling cover if you pay for accidental damage cover as an add-on to your insurance, although you will usually have to pay an accidental damage excess.

Accidental damage excess - what is it and do I have to pay it?

An accidental damage excess is the contribution you have to pay towards the cost of repairs if you make a claim on your insurance.

Accidental damage policies that include cover for misfuelling will typically only cover the cost of draining and cleaning your fuel tank if you haven’t driven your car at all. However, some policies don’t cover recovery costs but will instead cover the cost of repairing damage caused to your car and so you will have to arrange and fund getting your vehicle transported to an approved garage.

As there is little to no consistency between car insurance providers on whether or not you’re covered, we strongly recommend you thoroughly check your policy’s terms or contact your insurer to find out exactly what you are covered for.

Is misfuelling covered by breakdown cover?

Most mainstream breakdown recovery specialists only provide cover for taking your vehicle to the nearest repair centre. If you want roadside drainage of your fuel tank by the RAC or AA, you have to pay a fee, even if you’re a member.

How to get covered for misfuelling

  • Check if your insurer provides cover under your existing comprehensive policy (if you are fully comp) or if not, ask if you’re able to take out additional cover such as accidental cover and whether this covers you for recovery, drainage and repairs.
  • If your current insurer doesn’t provide misfuelling cover at all, you can take out a stand-alone specialist misfuelling policy instead.
  • Whilst none of the mainstream breakdown services provide cover for misfuelling, as standard, membership usually means they’ll take you, your passengers and your vehicle to the nearest garage for no additional fee. However, the RAC and the AA offer a roadside drainage service (depending on where you are and if they have a specialist van available) but you have to pay extra for this - usually around £250-£300 - even if you’re a member. There are reductions for existing members.

How much to fix putting wrong fuel in my car?

Usually the cheapest option for fixing misfuelling is to have cover in place before it happens.

Martin Lewis mentions a couple of the cheapest breakdown providers who offer a misfuelling service on his website as being AutoAid starting at £53.99 per year or Eversure Gold starting at £57.50 per year. However, both of these much cheaper breakdown providers do not have their own roadside assistance fleet like the RAC and AA and instead rely on local recovery services. So you could be kept waiting much longer than you would with a more elite service like the RAC or the AA.

If you don’t have cover for this issue, the costs of recovery, drainage and repair can be anywhere from £145 to £250. However, costs will depend on the severity of damage, what type of vehicle you have and whether you’ve driven it, and could cost as much as £5,000!

How to avoid putting the wrong type of fuel in your vehicle

  • Check the label: The way fuel pumps are labelled has (rather unhelpfully!) recently changed. Petrol pumps now display an ‘E5’ for standard unleaded petrol or ‘E10’ for the greener [lower emissions] type of petrol and diesel pumps are now labelled with a ‘B7’ inside a square.
  • Concentrate: Before filling your car with fuel, make a concerted effort to try and clear any brain fog so you don’t fill up in ‘autopilot mode’ and grab the wrong hose!
  • Make a note: Don’t be too embarrassed to tape a small neon sticky note to the inside your fuel cap with ‘DIESEL’ or ‘PETROL’ written on it. No one else is likely to notice your little note and even if they do, it’s not as embarrassing or traumatic as having to deal with the aftermath of misfuelling!
  • Check the nozzle size: If you’re struggling to get the nozzle in, this is usually a red flag that you’re trying to put diesel into a petrol car or conversely, if the nozzle seems too loose, you could be trying to put petrol into a diesel car.
  • Check the colour: More often than not, petrol hoses, nozzles and handles are green and diesel tends to be black, but they can be the same colour so don’t solely rely on this.

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