AdBlue in the diesel tank is a rapidly growing misfuelling problem. As more diesel vehicles — particularly Euro 6 cars, vans, and HGVs — require regular AdBlue top-ups, the risk of accidentally putting AdBlue into the diesel filler is increasing every year. Unlike petrol in diesel, AdBlue contamination is highly corrosive and can cause catastrophic damage to the fuel system within minutes of the engine being started.
AdBlue is a diesel exhaust fluid (DEF) made from a mixture of urea and deionised water. It is injected into the exhaust system of Euro 6 diesel vehicles to reduce harmful NOx emissions. AdBlue is stored in a separate tank (usually with a blue filler cap) and must be topped up regularly — typically every 10,000–15,000 miles. It is not a fuel additive and must never enter the diesel fuel system.
AdBlue is highly corrosive to the metals and rubber components used in diesel fuel systems. When AdBlue enters the diesel tank, it begins to crystallise as it dries, forming solid deposits that can block fuel filters and injectors. More critically, AdBlue reacts with the steel and aluminium components of the high-pressure fuel pump and injectors, causing rapid corrosion. Even a small amount of AdBlue in the diesel tank can cause irreversible damage if the engine is started.
Petrol in diesel causes damage primarily through loss of lubrication — the damage is mechanical and progressive. AdBlue in diesel causes damage through chemical corrosion — the damage is rapid and can be catastrophic even with very small quantities. A few hundred millilitres of AdBlue in a 60-litre diesel tank is enough to cause serious damage if the engine is started.
If the engine was not started: a specialist AdBlue decontamination service costs £300–£600. The fuel tank must be drained, thoroughly flushed, and all fuel system components inspected for corrosion. If the engine was started: expect costs of £1,500–£5,000+ depending on the extent of corrosion. In severe cases, the entire fuel system may need replacing. Some vehicles are written off.
Step 1: Do not start the engine under any circumstances. Step 2: Do not put the key in the ignition — on some modern vehicles, turning the ignition to position 1 (without starting) can activate the fuel pump. Step 3: Call a wrong fuel recovery specialist immediately. Step 4: Tell the operator exactly what happened — AdBlue contamination requires specialist decontamination equipment that differs from a standard petrol-in-diesel fuel drain.
Diesel in the AdBlue tank will contaminate the AdBlue fluid and can damage the SCR catalyst and AdBlue injector. Repair costs are typically £500–£2,000. The AdBlue tank must be drained and flushed, and the SCR system inspected. In most cases, the diesel fuel system itself is not affected — but do not start the engine until a specialist has assessed the situation.
Black Eagle Recovery provides specialist AdBlue contamination recovery across London, Kent, Surrey, Sussex, and Essex — 24 hours a day, 7 days a week. Our operators carry specialist AdBlue decontamination equipment and are trained to handle AdBlue contamination safely. Call 0330 520 1620 for an immediate quote and ETA.
Put AdBlue in the diesel tank? Do not start the engine. Call Black Eagle Recovery immediately on 0330 520 1620 — AdBlue decontamination specialists, available 24/7 across London and the South East.
Call 0330 520 1620Leave your details and we'll call you back.
Petrol in a diesel engine is the UK's most common misfuelling mistake — over 150,000 incidents every year. This guide explains exactly what happens to your engine, how serious the damage is, and what you must do (and must NOT do) the moment you realise your mistake.
Wrong fuel recovery costs vary depending on vehicle type, fuel contamination level, and location. This guide breaks down the typical costs for petrol in diesel, diesel in petrol, and AdBlue contamination — and explains what affects the final price.
Putting petrol in a diesel car — or diesel in a petrol — is more common than you think. The good news is that if you act quickly and follow the right steps, you can often avoid serious engine damage.
Black Eagle Assistant
24/7 · Instant answers
AI assistant · For emergencies call 0330 520 1620