AdBlue in Diesel Tank? Here’s How to Fix It

Did you accidentally pour AdBlue in your diesel tank? Don’t worry, you’re not the first one. With the surging number of vehicles using AdBlue, the number of drivers putting AdBlue in diesel tanks has also increased.

But don’t worry, I’ve got just the solution for you. Here is everything you need to know about AdBlue, and what you should do if you mistakenly pour Adblue in your diesel tank.

What is AdBlue?

The automobile industry concluded that they need to save the environment and find a fix for the messy diesel cars. The problem is that diesel cars are notorious for spitting out nasty gasses like nitrous oxide, which is highly dangerous.

So what was the solution? It was to insert a tiny quantity of urea inside the diesel exhaust generating a chemical reaction which supposedly converts nitrous oxide into nitrogen and water vapour. 

This synthetic urea was combined with deionized water and ultimately named “AdBlue.”

Even though it is not widely available yet, this process is present in newer diesel cars with SCR (selective catalytic reduction)

Which Cars Require AdBlue?

If you have a car that is registered after 2015, chances are you own a vehicle which uses AdBlue to minimize emissions. Typically if you possess a Euro 6-Diesel compliant BMW, Audi, Land Rover, Jaguar, Citroen, Peugeot or Mercedes-Benz, it likely runs on AdBlue technology. The car’s model often contains a clue in its names like ‘SRC’ or ‘Blue” written alongside.

What Would Happen if You Put AdBlue in A Diesel Tank?

To avoid confusion, vehicles typically sport a blue fill cap for Adblue tanks and green, red, or black for diesel tanks. Larger vehicles also generally position the diesel and Adblue fill caps far apart from each other. These precautions, sadly, are not enough, and if you happen to pour AdBlue into your diesel tank accidentally, there can be severe consequences.

Since the AdBlue fill cap sports a much smaller nozzle, you could accidentally pour diesel into it as the diesel’s nozzle is generally much broader. However, the other way around is quite common.

As it’s mostly composed of ionized water, it is similar to pouring water inside your vehicle’s diesel tank. Water and diesel simply do not mix so what happens when you try to start a diesel car on water? It’s not going to start!

Additionally, the urea is known to be very corrosive for the fuel system’s seals and pipes. It is also prone to crystallization, which can clog fuel filters and injectors.

This can cost you thousands of dollars worth of damage, and additionally, you won’t be able to use your vehicle unless it is completely drained out and repaired.

What to do if You Added AdBlue in Your Diesel Tank?

Adblue in diesel tank

Don’t Start Your Engine!

In an unfortunate situation where you inadvertently poured AdBlue in a diesel tank, absolutely refrain from starting the engine as this will spread the fluid around your vehicle’s fuel system. AdBlue is not compatible with many materials and metals such as steel, brass, zinc, aluminium and cast iron and will end up eroding the components and pipework. 

Remove AdBlue!

It is highly recommended that you contact a fuel technician to safely remove AdBlue from your vehicle’s diesel tank without causing further damage. You’ll need to have the fuel tank drained out to flush out the fuel filter and lines so that the compatible fuel can return to the vehicle’s fuel tank and your car can run like before.

In some instances, after the whole process is over, you may have to replace the fuel filter. All this will simply be too difficult for the average Joe, so it’d do you good to call a reputed technician. It might cost you, but it is far better than damaging your car and having to buy a brand new one.

AdBlue mix up happens every now and then, and you don’t have to panic, it can be resolved.

If you need more info check this article from wikipedia.


AdBlue is a relatively new innovation and is increasingly becoming popular due to its advantages. Mixing diesel and AdBlue is nothing new. Taking adequate precaution while adding AdBlue is definitely the safest approach, but even if you accidentally make a mistake, it is entirely reversible.

3 thoughts on “AdBlue in Diesel Tank? Here’s How to Fix It”

  1. Hi
    I just wanted to say thank you for a brilliant speedy job removing adlube from my diesel tank.
    Mr S P Varney
    I think the gentleman I spoke to at the call centre was called Alex and the technician who called at my home was called Shaba.
    Please pass on my thanks.

    1. Thank you so much for the review Michael,

      I have passed on the message to Darko who deserves all of the recognition that he deserves.

      Thank you for using Fuel Fixer, I am glad you had a great experience with us.

      – The Fuel Man

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