AdBlue in the Wrong Place? Here’s What to Do
AdBlue mistakes are more common than people realise — especially in diesel cars and vans. The good news is: it’s usually fixable, and acting quickly can prevent expensive damage.
This guide explains what happens if:
AdBlue is added to the fuel tank, or
diesel/petrol is added to the AdBlue tank,
and what to do next.
First things first
do NOT start the engine
What happens if AdBlue is put in the fuel tank?
AdBlue is a water-based solution. If it enters the fuel system, it can cause serious problems because it doesn’t mix correctly with diesel and can lead to:
Contamination in fuel lines
Filter blockage
Damage to pumps and injectors
Corrosion or crystallisation over time
If the engine has not been started, a professional drain and flush can often prevent long-term damage.
What happens if fuel is put in the AdBlue tank?
The AdBlue system is separate from the fuel tank, but it’s sensitive. Adding fuel to the AdBlue tank can cause:
AdBlue system warnings and faults
Sensor and pump issues
Reduced emissions system performance
Potential system contamination
This situation still needs attention, but it’s usually manageable when dealt with quickly.
Not sure where it went?
Here are quick clues:
AdBlue nozzle usually doesn’t fit the fuel filler, but mistakes can still happen
Some vehicles have AdBlue fillers in the boot, under the fuel flap, or by the spare wheel
If you used a jerry can or bottle, errors are more likely
If you’re unsure: Don’t guess — it’s safer to get advice before doing anything else.
Avoid these common mistakes
Do NOT:
Try to “dilute” it with diesel
Start the engine “just to test”
Drive to a garage
Attempt a DIY drain unless you’re properly equipped
These actions often turn a simple fix into an expensive repair.
Is AdBlue misfilling repairable?
Yes — in many cases.
Typical solutions include:
Safe tank drain
System flush (if required)
Refilling with the correct fluid
Clearing warning codes where applicable
The sooner it’s handled, the better.
When to call a wrong fuel specialist?
You should call for professional help if:
You’ve put Adblue in the wrong place
You’re unsure whether the engine was started
The car won’t start after refuelling
A dashboard warning light appears
A specialist can advise you immediately and attend your location if needed.
FAQs
AdBlue in the wrong place – common questions
Can I drive if AdBlue went in the fuel tank?
It’s safest not to. Driving increases contamination through the fuel system.
What if I only added a small amount?
Even small amounts can cause issues. Advice is recommended.
Is this common in vans and work vehicles?
Yes — especially where vehicles are shared or drivers swap between vehicles.
Put the wrong fuel in your car? Don’t start it.
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