Put AdBlue In My Diesel Car

What Happens When You Put AdBlue in Diesel?AdBlue is a high-purity urea solution used in modern diesel engines equipped with Selective Catalytic Reduction (SCR) technology to reduce nitrogen oxide (NOx) emissions. Its introduction has been a significant step towards meeting stringent emission regulations (external). However, accidental misfuelling—putting AdBlue in a diesel tank—can cause severe engine damage and operational issues. Understanding the consequences of this mistake and the steps to rectify it is crucial for vehicle owners.

The Role of AdBlue in Diesel EnginesBefore delving into the ramifications of misfuelling, it’s essential to understand the role of AdBlue in diesel engines. AdBlue is injected into the exhaust stream of diesel vehicles. In the SCR system, it reacts with the NOx gases produced during combustion, converting them into harmless nitrogen and water vapor. This process significantly reduces the amount of harmful emissions released into the atmosphere.

Misfuelling
AdBlue in the Diesel TankDespite different fillers and labels, accidents do happen. Misfuelling can occur due to various reasons—confusion at the pump, lack of attention, or unfamiliarity with the vehicle’s requirements. Unlike putting petrol in a diesel tank or vice versa, the consequences of putting AdBlue in a diesel tank are severe due to the chemical nature and purpose of AdBlue.

Immediate Consequences:

Chemical Reaction and Corrosion:
AdBlue is composed of deionised water and urea. When it mixes with diesel, it can form crystals and cause corrosion. Urea can break down into ammonia, which corrodes metal parts in the fuel system.

Fuel System Contamination:
The mixture of AdBlue and diesel creates a sludgy substance that clogs filters, fuel lines, and injectors. This contamination can lead to stalling, misfiring, or complete engine failure.

Engine Damage:
Running a contaminated engine can lead to severe damage to injectors, combustion chambers, and other critical components.
If you’ve made this mistake, visit our AdBlue Misfuelling Help page for immediate assistance from our national mobile fuel drain experts.

Long-Term Consequences

• Expensive Repairs: Cleaning or replacing the fuel system is often costly and time-consuming.
• Voiding Warranties: Most manufacturers consider misfuelling a user error, voiding the warranty.
• Operational Downtime: For commercial vehicles, this downtime can be highly disruptive and costly.

For fleet vehicles, our commercial fuel drain services help get you back on the road fast.
Immediate Steps to TakeIf you realise AdBlue has entered the diesel tank:

1. Do Not Start the Engine – This prevents contaminated fuel from circulating.
2. Call a Professional – Contact Fuel Doctor UK 24/7 for nationwide emergency fuel drain support.
3. Drain and Flush the System – A full drain and system flush is essential to remove AdBlue and restore engine integrity.

Prevention Tips

• Education: Ensure drivers understand the difference between diesel and AdBlue.
• Use Safeguards: Most vehicles have filler necks that prevent cross-contamination—always use the right pump.
• Regular Maintenance: Helps identify potential damage early before it becomes catastrophic. Book a vehicle diagnostic to stay ahead of issues.

​Putting AdBlue in a diesel tank is a costly mistake, but quick action and professional help can limit the damage. Whether you're a private car owner or manage a fleet, knowing the risks and proper response can save you thousands in repairs. Trust Fuel Doctor UK to help you fix misfuelling mistakes quickly and efficiently.