Contaminated fuel in a Mercedes GL 420 CDI? Petrol in your Diesel Mercedes?

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


Putting Petrol in a Diesel Mercedes is a well-known mistake. And its remedy depends upon several factors. In case you would like to find out what you have to do about this then stay with me.
These are the most crucial variables to take into consideration whenever deciding on whether or not to have a fuel drain:

  1. What amount of Petrol did you put in the Mercedes, taking into consideration that the fuel tank capacity of your Mercedes GL 420 CDI is usually about 100 litres?
    1. Hardly any Petrol, as little as 5 litres of Petrol in a Diesel GL 420 CDI will usually not necessarily be a huge problem. Experience has proven to us that an amount under 5 litres (which is about 5% of the total fuel tank) is very often capable of being sufficiently diluted by entirely filling the remainder of the tank with Diesel.
      It is relatively unusual to come across a car having difficulties due to under 5% incorrect fuel contamination. Do not forget that it is very infrequent - certainly not impossible to find. There are actually certain vehicles that don't stand any degree of fuel contamination at all.
    2. Somewhere between 5 and 10 litres of Petrol in the Mercedes (from 5 to 10%) is a 50/50 scenario. Our working experience demonstrates that as many drivers get away with it as those who break down. Any time you are deciding upon whether or not to risk it and just simply fill it up recognise that it is much like betting all of it on black - you have got a 50/50 chance of it working.
    3. Anything more than 10 litres of Petrol in your Diesel GL 420 CDI should as soon as possible be drained seeing that your probability of getting away with that quantity of contamination is undoubtedly lower than one in fifty - definitely big odds.
  2. Put some Petrol in a Diesel Mercedes and drove it: Have you noticed any performance problems ever since putting the wrong fuel in your GL 420 CDI? In that case, have it emptied regardless of the volume of Petrol or the contamination percentage. Still running an automobile that is already starting to suffer the effects of wrong fuel contamination will definitely bring about more and more damage being caused to the fuel system parts.
  3. Are you interested in peace of mind?
    Then simply just get it emptied. Regardless of contamination percentage, there is always some amount of threat linked with running a Diesel motor on Diesel contaminated with Petrol. Probable final outcomes of driving on the wrong fuel normally include the motor not starting, running unevenly, loss in power, wearing of the high-pressure pump, damaged or blocked injectors, and so on. These are some of the most typical Petrol in Diesel warning signs, and should you notice any of them stop and get it drained asap.

Keep away from getting any jack-of-all-trades to attend your car. We are Mercedes specialists and have got the certification and experience necessary to make sure that you get back on the road with little hassle or worry.

Put Petrol in a Diesel Mercedes

Inadvertently put Petrol in a Diesel Mercedes? Or perhaps even put contaminated fuel in your Mercedes GL 420 CDI?

Contact us for Assistance & Recommendations

Call us and receive honest advice and practical assistance for your precise circumstances

We come out and drain it

We are able to go to you to undertake the full fuel removal & clean there on scene

Once completed You Get Going 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 top rated wrong fuel drain professionals in the UK, offering countrywide coverage, for Mercedes motorists in particular. We typically attend to:

  • Unleaded petrol in your Diesel Car
  • Diesel in Unleaded Petrol Car
  • AdBlue contamination
  • Water fuel contamination

We are Mercedes specialists and have successfully drained thousands of Diesel Mercedes vehicles. Even if it's roadside, on a petrol station forecourt, or even at your home, we can get you going again.

The Procedure

The procedure of draining Petrol from a Diesel car is fundamentally identical for most motor vehicles. Naturally it can vary slightly as every brand has their particular distinct fuel system. Nevertheless it still fundamentally follows the below guidelines:

Petrol in Diesel Mercedes

Fuel Drain

Empty the Fuel Tank

View more
Wrong Fuel Drain Mercedes

System Flush

Clean out the fuel lines & pumps

View more
Petrol in Diesel Drain Mercedes

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

Petrol in Diesel Questions

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

I put Petrol in a Diesel 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 Diesel car on Petrol 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 Petrol can I get away with in a Diesel 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 Diesel 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

In case you have any queries or require assistance please Contact Us!
We can get you going once again.

24/7 Mercedes Helpline

0333 366 0103

Our Business Office

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

Weekdays: 9am to 5pm

Important Info

Fully Insured

VAT Registered

APEX Certified


Fully Mobile

Professionally Trained