Wrong fuel in a BMW 840i? Diesel in a Petrol BMW?

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BMW Fuel Drain


Filling Diesel in a Petrol BMW is a regularly occurring problem. And its remedy will depend on a number of factors. Assuming you would like to know what you must do about this then keep on reading.
Listed here the main factors to think about when making a decision whether to have a fuel drain:

  1. What amount of Diesel did you put in to the BMW, taking into consideration that the fuel tank capacity of the BMW 840i is probably around 90 litres?
    1. A modest amount of Diesel, as little as 4.5 litres of Diesel in a Petrol 840i will quite often not necessarily be a major problem. Experience has shown us that an amount less than 4.5 litres (which is about 5% of the overall fuel tank volume) is often capable of being completely diluted by entirely filling up the remainder of the tank with the right fuel.
      It is pretty rare to encounter a car going through problems due to under 5% incorrect fuel contamination. Remember that it is uncommon - certainly not impossible to encounter. There are actually certain cars that will not endure any level of contamination at all.
    2. Anywhere between 4.5 and 9 litres of Diesel in the BMW (from 5 to 10%) is a 50/50 situation. Our experience demonstrates that as many motorists get away with this as all those who don't. Any time you are deciding whether or not to risk it and basically fill it up consider that it is exactly like betting all of it on black - you've got a 50/50 possibility of it being ok.
    3. Anything over 9 litres of Diesel in your Petrol 840i ought to as soon as possible be removed since your probability of driving with this level of contamination is in all likelihood below one in 50 - truly big odds.
  2. Put some Diesel in a Petrol BMW and drove it: Have you seen any kind of performance concerns after putting the bad fuel in your 840i? In that case, get it removed regardless of the quantity of Diesel or the contamination ratio. Proceeding to drive driving an automobile that is already beginning to suffer the consequences of fuel contamination will only be responsible for more damage affecting your fuel system parts.
  3. Are you looking for assurance?
    In that case get it emptied. No matter the contamination ratio, there is always some amount of danger connected with operating a Petrol motor on Petrol contaminated with the wrong fuel. Probable final outcomes of driving on the wrong fuel normally include the motor refusing to start, running unevenly, reduced power, wearing of the high-pressure pump, damaged or bunged injectors, and so on. These are a few of the commonest Diesel in Petrol signs or symptoms, and in the event that you detect any of them stop driving and have it drained right away.

Keep away from getting any unqualified mechanic to try to drain your vehicle. We are BMW specialists and possess the certification and working experience necessary to ensure that you get back on the road with minimum hassle or worry.

Put Diesel in a Petrol BMW

Unintentionally put Diesel in a Petrol BMW? Or even put contaminated fuel in your BMW 840i?

Call us for Help & Guidance

Call us and get honest advice and sensible assistance for your specific circumstance

We show up and do the fuel drain

We can reach you to perform the full contaminated fuel drain & flush there on scene

Once performed You Get Moving Once again

As soon as we are done you are able to get back on the road and get on with your day

Wrong Fuel Drain Specialists

We are the primary wrong fuel drain professionals in the UK, having national coverage, for BMW motorists particularly. We mostly attend to:

  • Unleaded petrol in a Diesel Car
  • Diesel in an Unleaded Petrol Car
  • AdBlue fuel contamination
  • Water fuel contamination

We are BMW specialists and have successfully drained thousands of Petrol BMW vehicles. Regardless of whether it's at the roadside, on a filling station forecourt, or even at your home, we can get you going again.

The Process

The technique of extracting Diesel from a Petrol car is basically similar for a large number of vehicles. Naturally it can differ a little as every brand has their unique different fuel system. Nevertheless it still fundamentally observes the below guidelines:

Petrol in Diesel BMW

Fuel Drain

Empty the Fuel Tank

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Wrong Fuel Drain BMW

System Flush

Clean out the fuel lines & pumps

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Petrol in Diesel Drain BMW

Vehicle Restart

Get the car up and running again

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Diesel in Petrol FAQs

When someone has put Diesel in a Petrol car they have a few very common questions. So we have compiled a list of the most Frequently Asked Questions for you

I put Diesel in a Petrol car and drove it. What do I do?


Turn off the car as soon as possible and call us. Continuing to run a vehicle on the wrong fuel can potentially damage it. We will be able to give you advice and assistance based on your circumstances

Will driving a Petrol car on Diesel cause damage to it?


It can. However, if the problem is caught and remedied quickly the risks will be minimal. Of the 1,500 vehicles we attend every month, less than 0.5% have suffered and substantial damage requiring parts replacement.

How much Diesel can I get away with in a Petrol car?


The safe answer is none. However you might be able to get away with a very low contamination ratio. That being said, we always highly recommend draining anything over a 5% contamination ratio asap.

I know about petrol in diesel, but what about Super Unleaded?


Putting Super Unleaded, or Shell V-Power, BP Ultimate Unleaded, etc, will have the exact same effect as putting regular unleaded petrol in your diesel car and will need to be drained out and flushed.

Will getting you to do a fuel drain void my warranty?


No! The EU Block Exemption Regulations clearly state that "the work can be carried out by as long as that garage uses manufacturer approved parts and correctly follows the manufacturer's service schedule."

Can I top it up with Petrol and add some 2-stroke oil?


This might work on some vehicles in some cases, but in the majority on instances it won't and you risk damaging the Lambda sensors as well as fuel pump and injectors, just as a regular misfuel.

Call us

Should you have any enquiries or require some assistance please Contact Us!
We are able to get you going again.

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0333 366 0103

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Fuel Fixer Ltd, Linx House, 147 London Road, East Grinstead, RH19 1ET


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