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?

AdBlue is a solution made from a mixture of water and urea, designed for use in diesel engines to reduce nitrogen oxide (NOx) emissions, which contribute to air pollution and have harmful effects on human health and the environment.

AdBlue works by converting harmful NOx emissions into harmless nitrogen and water vapor. This occurs through a chemical reaction in the catalytic converter, a process known as Selective Catalytic Reduction (SCR).

The automotive industry recognized the need to mitigate the environmental impact of diesel engines, which are known for emitting high levels of NOx, a dangerous pollutant.

The solution was to introduce a small amount of urea into the diesel exhaust system, initiating a chemical reaction that converts NOx into nitrogen and water vapor. This synthetic urea, combined with deionized water, is what we now call “AdBlue.”

While AdBlue is not yet universally available, it is being used in newer diesel vehicles equipped with SCR technology to help meet stricter emission standards.

Problems That Arise When Using Adblue


AdBlue is a delicate liquid that can easily become contaminated if it comes into contact with other substances, such as diesel fuel or oil. This can make AdBlue less effective, leading to increased NOx emissions and potential damage to the engine.

Hence, you must use high-quality AdBlue that meets the ISO 22241 standard. This standard guarantees that AdBlue is pure and does not contain pollutants. Additionally, store AdBlue appropriately since exposure to high temperatures and sunlight can cause it to deteriorate and lose effectiveness.

Incorrect Dosing

AdBlue dosage is a critical factor in reducing NOx emissions. Incorrect dosing can lead to increased emissions and potential damage to the engine.

To ensure correct dosing, use an AdBlue system that is calibrated and maintained correctly. Regular checks should be performed to ensure the system is functioning correctly and the correct amount of AdBlue is being injected into the exhaust system.

You should also use the appropriate AdBlue tank size for the vehicle and ensure the tank is kept topped up to prevent the engine from running without AdBlue, which can cause damage. For instance, if the AdBlue tank runs dry, the engine may go into a reduced power mode, and in severe cases, it may not start at all. 

Freezing at Low Temperatures

AdBlue tends to freeze at low temperatures, which can cause issues with dosing. Hence, storing AdBlue in a location not exposed to freezing temperatures is recommended. If the AdBlue does freeze, it can be thawed in a warm location or using a thawing agent. 

It is also important to note that using AdBlue that has been frozen and thawed may affect its quality and effectiveness, so it is best to avoid using it if possible. 

Ran Out of Adblue

There are times when you may run out of AdBlue. In this case, refilling the AdBlue tank as soon as possible is important to ensure the proper functioning of the vehicle’s emissions system. Driving without AdBlue can cause the vehicle to go into limp mode, which limits the engine’s power and speed.

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.

Final Thoughts

AdBlue has become a necessary component for modern diesel engines, but it can also lead to various problems if not handled properly. From contamination to incorrect dispensing, the potential issues are numerous. However, these issues can be avoided by adhering to the manufacturers’ recommendations and guidelines and ensuring proper AdBlue storage, handling, and usage.

Need AdBlue for your fleet? Fuel Fixer has got you covered! Our top-quality AdBlue solution is perfect for reducing emissions and ensuring your vehicles meet environmental standards. With Fuel Fixer, you can be sure of getting the best AdBlue at competitive prices, delivered right to your doorstep. Contact us today to get started!

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

Leave a Comment

Your email address will not be published. Required fields are marked *