AdBlue mix-up? Leave it off.
Many modern diesels have two fillers side by side: one for diesel and one for AdBlue. Mixing them up is easy to do, and both need sorting before the engine runs.
What we actually do.
Switch "Engine started?" to Yes to see why stopping straight away matters.
How we fix itPick what happened, then press and hold the button.
1 · Drain the wrong fuel
Ignition off
Keep it off until the fuel's drained.
A simplified view of a real job. Every vehicle is different, so call us about yours.
Then we clean the lines.
If the engine ran, the wrong fuel isn't just in the tank. It's in the fuel lines, the filter and the injector rail too.
Cleaning the fuel linesIf the engine ran, the wrong fuel is in the lines, the filter and the injector rail, not just the tank. Hold the button to flush it through.
Contaminated fuel in the lines
Clean fuel is pushed through from the tank end and the contaminated fuel comes out into a sealed jar.
What happens
AdBlue in the fuel tank: AdBlue is a water-based solution of urea used to clean exhaust gases. It isn't a fuel. In the fuel system it can cause corrosion and crystals that damage the pump and injectors, so it must not be pumped through.
Fuel in the AdBlue tank: diesel or petrol in the AdBlue tank can damage the exhaust cleaning system (often called SCR). The vehicle may show warning lights and can go into reduced power.
Signs if it's been driven
If you didn't notice at the pump, these are the usual signs. Pull over safely, switch off and call us.
- Engine runs briefly then cuts out
- AdBlue or emissions warning light
- Engine warning light on
- Loss of power or limp mode
- Won't start
- Unusual smell or smoke
How we fix it
We drain the contaminated tank and flush what we can safely reach at the roadside, then refill with the right fluid. Some AdBlue system contamination needs dealer equipment to fully clean; if we think yours does, we'll tell you straight away, before you pay for anything.
- 1
Drain
We pump the wrong fuel out through the filler neck, fuel lines or sender unit.
- 2
Flush
We flush the fuel lines so contaminated fuel isn't left in the system.
- 3
Refill
The right fuel goes in. Fill to at least three-quarters to dilute anything left.
- 4
Drive
Receipt sent to your phone. Book a new fuel filter at a garage soon.
Afterwards
- Fill to at least three-quarters with the right fuel to dilute any small trace left.
- Have the fuel filter replaced at a garage as soon as you can.
- If a warning light stays on, or it runs roughly, stop and get it checked, and let us know.
- Keep your receipt for any insurance claim.
Questions
I put AdBlue in the diesel tank but didn't start it. Is that OK?
That's the best case. Leave it off and call us. Draining it before the engine runs keeps it out of the pump and injectors.
Can you fix fuel in the AdBlue tank?
Often, yes: we drain the AdBlue tank and refill. If the contamination has gone further into the system, it may need a dealer or specialist, and we'll be upfront about that.
Why is AdBlue so bad in the fuel tank?
It's mostly water with urea. It doesn't burn, it doesn't lubricate, and it can corrode and crystallise inside a diesel fuel system.
We fix all of these.
Just done it?
The four things to do in the next five minutes.
What to do now →
Petrol in diesel
The most common mix-up, and the one to deal with fastest.
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Diesel in petrol
Harder to do, but it still stops a petrol engine.
Read more →AdBlue mix-ups
AdBlue in the fuel tank, or fuel in the AdBlue tank.
Read more →Questions?
Cost, insurance, what happens next, and more.
All answers →