AdBlue™ in diesel tank

AdBlue™ in diesel tank: The problem and solution

In order to meet Emission Standards, diesel consuming vehicles need to reduce their emissions down to certain levels depending upon the engine size. In response to this, a pollution control technology known as the Selective Catalytic Reduction (SCR) system has been installed into vehicle exhaust systems, which uses AdBlue™ to reduce the Nitrous Oxides present in emissions. AdBlue™ is a registered trademark for Diesel Exhaust Fluid (DEF); a solution comprised of 32.5% urea mixed with de-ionised water.

AdBlue™ is commonly mistaken as a fuel additive, when in fact it should not be contaminated or mixed with diesel at all. Whereas diesel is for the running of the engine, AdBlue™ is designed for the SCR system in the exhaust and consequently is dispensed into a completely different tank to the diesel.

Whilst AdBlue™ has been used in some vehicles since 2005 when the Euro Emission Standards were first introduced, regulation updates have seen more and more vehicles needing to comply and it now covers all new trucks, buses, agricultural and plant equipment as well as some passenger cars.  For many, AdBlue™ is still a relatively new issue and filling up the vehicle with both diesel and AdBlue™ is not yet second nature. Even for those that are used to it mistakes still happen. Just look at how often people put petrol in their diesel car. So what happens if you accidently put AdBlue™ in your diesel tank?

What happens if I accidently put AdBlue™ in my fuel tank?

To help avoid confusion, a lot of vehicles have a blue fill cap for the AdBlue™ tank and black, red or green for diesel, and sometimes on larger vehicles such as HGVs the AdBlue™ and diesel fill points are positioned quite far away from each other. However this isn’t fool proof and a driver mistakenly putting AdBlue™ into the diesel tank can have disastrous consequences.

Image adapted from © Photo by Kickaffe (CC BY-SA 4.0) 

Generally speaking, accidentally filling diesel into your AdBlue™ tank is unlikely as the AdBlue™ filler cap is designed for a smaller spout nozzle (19mm), making it impossible for larger diameter diesel nozzles to fit. The other way round however has become a common problem amongst drivers of vehicles with new SCR systems and causes costly damage.

If the unfortunate situation arises that a driver has added AdBlue™ in the diesel tank, do not start the engine as this will circulate the fluid round the vehicle’s fuel system. AdBlue™ is not compatible with many metals and materials that make up the internals of the fuel system including cast iron, steel, brass, aluminium and zinc, so it can corrode the pipework and components. This can cost thousands of pound worth of damage, not to mention the loss of use of the vehicle until the tank is drained and all repairs have been carried out. You need to get a professional to drain the tank and flush out the system before starting the vehicle. So what can you do to prevent drivers from putting AdBlue™ in the fuel tank?

How do I make sure I don’t put AdBlue™ in my diesel tank by mistake?

Centre Tank Services offer a solution in the form of the nozzle used to dispense the AdBlue™. The Piusi SB325 AdBlue™ nozzle is available with a magnetic miss-filling spout. Thanks to the magnetic miss-filling spout, the AdBlue™ nozzle can only release fluid into a fill point that has a partnering magnetic adaptor inserted into it. With a magnetic collar fitted in the AdBlue™ fill point only, the AdBlue™ nozzle can physically not dispense into the diesel tank as there is no magnet to open the spout.

To meet ISO standards, many new AdBlue™ using vehicles and plant machinery have a magnetic collar inserted into the AdBlue™ fill point at manufacturing stage.  The issue is that often the dealers of the vehicle or machinery aren’t necessarily aware of this feature so don’t pass the information onto the owner that it exists. If the user isn’t aware and opts for a dispensing system with a standard nozzle rather than the available magnetic nozzles, miss-filling will not be prevented and the benefit of the magnetic collar is wasted.

You should be able to see whether your vehicle already has the magnetic adaptor by simply looking into the AdBlue™ fill point for something that looks like the below. If you aren’t sure whether you’re looking at the right thing then you could hold something like a screwdriver into the fill point and see whether you can feel the magnetic force.  If you do, simply replacing your existing nozzle with a magnetic spout model will prevent the risk of AdBlue™ being miss-filled into the diesel tank.  

If you don’t think your vehicle already has a magnetic collar fitted you can purchase a retrofit adaptor to insert yourself, and replace your nozzle with the magnetic spout model. You can purchase the SB325 magnetic miss-filling nozzle or read about it in more detail here.

What do I do if I have miss-filled AdBlue™ into my fuel tank?

These are the recommended steps to take should you put AdBlue™ in your fuel tank by accident:

  • Don’t turn on your vehicle engine

  • Drain the tank and dispose of the contaminated fluid safely

  • Get a trained technician to check the damage caused by the miss-filling and replace the filters that will have absorbed the AdBlue™.

  • Contact the vehicle manufacturer or dealer for official replacement parts that have been damaged or corroded.

  • Consider a magnetic AdBlue™ fill point adaptor (if you vehicle doesn’t already have one fitted) and magnetic spout nozzle so that AdBlue™ cannot be dispensed unless in contact with the fitted fill point adaptor. Available here.

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