Contaminated fuel in a BMW 850i? Diesel in a Petrol BMW?

We can help!
Call us: 0333 366 0103
BMW Fuel Drain


Putting Diesel in a Petrol BMW is a fairly typical problem. And what you want to do about it depends upon a few factors. If you would like to find out what you ought to do about it then read on.
Listed here are the main variables to take into consideration when choosing whether to have it drained:

  1. Exactly how much Diesel have you put in to the BMW, considering that the fuel capacity of your BMW 850i is most likely roughly 90 litres?
    1. Hardly any Diesel, something like 4.5 litres of Diesel in a Petrol 850i will more often than not not necessarily be a big problem. Experience has demonstrated to us that quantities less than 4.5 litres (which is 5% of the total fuel tank volume) is very often able to be sufficiently diluted by means of wholly topping up the remainder of the tank with the correct fuel.
      It is extremely rare to come across a car or truck experiencing problems with below 5% incorrect fuel contamination. Keep in mind it is infrequent - certainly not impossible to encounter. There are actually a few automobiles that won't stand any level of contamination at all.
    2. Somewhere between 4.5 and 9 litres of Diesel in the BMW (5 to 10%) is a 50/50 situation. Our experience has revealed that as many people get away with it as all those who don't. Any time you're deciding whether to chance it and basically top it up recognise that it is just like wagering everything on black - you have got a 50/50 chance of it being ok.
    3. Anything more than 9 litres of Diesel in a Petrol 850i should really immediately be removed because your probability of getting away with that level of contamination is in all likelihood below one in 50 - seriously huge odds.
  2. Put Diesel in a Petrol BMW and drove it: Have you noted any performance problems after putting the incorrect fuel in your 850i? In that case, have it drained regardless of the quantity of Diesel or even the contamination percentage. Proceeding to drive driving an automobile that is now beginning to suffer from the consequences of fuel contamination can likely cause even more harm affecting the fuel system components.
  3. Are you looking for peace of mind?
    Then simply just get it drained. Regardless of the contamination percentage, there is invariably some degree of threat connected with driving a Petrol motor on Petrol contaminated with the wrong fuel. Possible consequences of driving on the wrong fuel can include the motor not starting, running lumpy, lack of power, wearing of the high-pressure pump, damaged or blocked injectors, and so on. These are a few of the most frequently seen Diesel in Petrol warning signs, and in the event that you recognise any of them then cease driving and get it drained right now.

Do not simply have any untrained so-and-so to attend your car. We are BMW experts and possess the qualifications and expertise necessary to ensure that you get back on the road with minimal hassle or trouble.

Put Diesel in a Petrol BMW

Inadvertently put Diesel in a Petrol BMW? Or perhaps even put contaminated fuel in your BMW 850i?

Give us a call for Assistance & Guidance

Call us and receive honest advice and sensible help for your particular circumstance

We come out and drain it

We are able to come to you to undertake the fuel drain & clean there on scene

All done & You Get Moving Once again

When we are done you will be able to get back on the road and get on with your day

Wrong Fuel Drain Specialists

We are the leading wrong fuel drain experts in the UK, offering countrywide coverage, for BMW motorists especially. We predominantly deal with:

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

We are BMW specialists and have successfully drained thousands of Petrol BMW vehicles. Whether or not it's at the roadside, on a petrol station forecourt, or even at your home, we can get you going once again.

The Procedure

The method of draining Diesel from a Petrol vehicle is generally exactly the same for virtually all vehicles. Obviously it can differ slightly as each make has their own different fuel system. Nevertheless it still generally observes the below guidelines:

Petrol in Diesel BMW

Fuel Drain

Empty the Fuel Tank

View more
Wrong Fuel Drain BMW

System Flush

Clean out the fuel lines & pumps

View more
Petrol in Diesel Drain BMW

Vehicle Restart

Get the car up and running again

View more


Hours a Day


Days a Week





Our Partners

Just some of the few people we work with to bring you the best petrol in diesel service possible

Diesel in Petrol Questions

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.

Contact Us

In case you have any questions or want our assistance please Call us!
We are able to get you going once again.

24 hour BMW Helpline

0333 366 0103

Our Corporate Office

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

Important Info

Fully Insured

VAT Registered

APEX Certified


Fully Mobile

Professionally Trained