Does car insurance cover putting the wrong fuel in your car?
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Misfuelling and insurance
Misfuelling damage
Adblue damage
Avoid misfuelling

Misfuelling can lead to a pretty hefty repair bill but you may be able to get cover through your car insurance.

It’s an easy mistake to make. Around 150,000 UK drivers put the wrong type of fuel in their cars each year.

Here’s everything you need to know.

Misfuelling cover varies between insurers

Some insurers offer cover for misfuelling but it varies a lot between companies.

It can cost around £200 to drain and clean your fuel tank, £2,000 to repair an engine and as much as £9,000 to replace it altogether.

Some insurers cover the cost of everything, but others may only pay out for you to get your tank cleaned and drained.

More companies are excluding misfuelling from standard policies and instead offer misfuelling cover as an add-on, which can make insurance more expensive.

If your insurer does cover misfuelling, you should contact them as soon as possible to make a claim.

You may have to pay an excess, which is a chunk of money that you pay towards the claim.

In some cases, your insurer may decide to write off your car as “category S” if they don’t think it’s worth paying out to fix it.

Instead, your car will be valued and you’ll get a lump sum payment. Written-off cars aren't "roadworthy" anymore, so you’ll have to pay for repairs yourself before it’s legally allowed on the road again.

If your insurer doesn’t cover misfuelling (our policies don't), you may be able to claim for draining and cleaning through accidental damage or breakdown cover if you have it.

Why misfuelling can severely damage your car

Diesel and petrol engines work differently and need their specific fuel types to function.

So, putting the wrong fuel in the tank could lead to a lot of damage.

Putting petrol in a diesel car

It’s more common for drivers to put petrol in diesel cars because petrol nozzles are smaller and can easily fit into a diesel tank.

It can cause a lot of damage to the engine if you don't notice. In extreme cases it could lead to a car being written off.

This is because diesel fuel pumps need lubrication to work properly but adding petrol has the opposite effect and causes friction between the metal parts.

Signs that you’ve put petrol in a diesel car include:

  • Lots of smoke coming from the exhaust
  • A loud knocking sound when you accelerate
  • The engine warning light turning on
  • The engine stopping completely

Putting diesel in a petrol car

Putting diesel in petrol cars is less common because diesel nozzles tend to be wider and don’t fit into petrol tanks very easily.

Petrol fuel needs to be ignited by a spark from the spark plugs to get your car going. But adding diesel clogs up the plugs causing the fuel system to fail and your car probably won’t start.

While it can be annoying, it’s a lot less damaging than putting petrol in a diesel engine and shouldn’t cause any permanent damage once the fuel is drained out.

Signs that you’ve put petrol in a diesel car include:

  • Lots of smoke from the exhaust
  • The engine misfiring
  • The engine cutting out and not restarting

If you spot that you misfuelled your car before you start the engine, let someone at the petrol statiion know and call your insurer or breakdown company straight away.

You’ll need to get your fuel tank drained to stop the engine getting damaged.

If you drive off before you notice, you’ll still need to get in touch with your insurer or breakdown company to get your engine repaired or replaced.

If your car needs more work, like repairing or replacing the engine, it may not be covered though and you’ll have to pay out of pocket.

Check your policy document to see if you’re covered for misfuelling and if anything’s unclear, give them a ring to double check.

Important
Misfuelling can damage your car. Sometimes, the damage will be so big that your insurer could write your car off.

Adblue can severely damage your engine too

Drivers often mistake Adblue for a "fuel additive" but it can cause a lot of damage if it ends up in your engine.

Adblue is an exhaust fluid that turns nitrogen oxide into nitrogen and steam so that cars meet an emissions standard called Euro 6.

If you accidentally put Adblue in your fuel tank, don’t start your car.

You’ll need to contact an emergency car service to drain your tank as soon as possible.

You may be able to make a claim for the cost of draining through insurance, depending on your policy.

How to avoid misfuelling

It's good to stop yourself from getting distracted when you fill up your car. Avoid things like using your phone.

Pay close attention to the pump labels as well and always double-check the pump triggers which show the fuel type too.

If you’ve got a diesel car, you can buy a stopper that keeps petrol nozzles from fitting the filler neck.

They tend to cost £15 - £30, and the designs vary depending on the make and model of your car.

Updated on 28th May 2020

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