AdBlue crystallisation
AdBlue crystallisation is the white deposit left when the fluid dries — around the dosing injector, the filler and any leak. It blocks the injector and it corrodes what it sits on. Call 01293 248666.
Urea solution leaves solid urea behind as its water evaporates. At a leaking joint that means a visible white crust. At the dosing injector tip, which runs hot in the exhaust stream, it means a progressively restricted orifice and a dosing pressure fault. Crystallisation is usually a symptom of something else — a weeping seal, a partially blocked injector, poor-quality fluid or repeated short journeys where the system never gets through a full dosing cycle.
Call 01293 248666 From just £89 call-out fee
This is not a drain job, so it is not work we do. AdBlue in Fuel drains and flushes AdBlue contamination — AdBlue put into a fuel tank, or diesel, petrol, water, screenwash or oil put into the AdBlue tank. That is the whole service. AdBlue crystallisation is an SCR system fault, and it is fixed by a garage or a franchised dealer with the right diagnostic tooling, not by draining a tank at the roadside.
The page below is here because the question gets asked constantly and the answers online are poor. It is reference material, not a sales page. There is no call-out price quoted for it, because we would not be the ones attending. If you are not certain which of the two you are looking at, call 01293 248666 and describe it — if it is a drain we will quote it, and if it is not we will say so and you will not be charged for the conversation.
AdBlue crystallisation — the severity verdict
| Severity | Likely recoverable Usually resolved by a drain and flush, with a fluid-quality check afterwards. |
|---|---|
| What this is | AdBlue crystallisation — an SCR system fault, not a contaminated tank |
| Who fixes it | A garage or franchised dealer with SCR diagnostic tooling |
| Do we do it? | No. AdBlue in Fuel drains AdBlue contamination only |
| Typical cost | £150–£480 at a garage — a guide figure, not our quote |
| If you are unsure | 01293 248666 — we will tell you which of the two it is |
What to do right now
- Photograph where the white deposit actually is — filler, tank seam, line joint or exhaust.
- Rinse external crystals off paint and metal with water before they corrode it.
- Do not chip deposits off the injector.
- Call 01293 248666.
What a technician actually does
Source of the leak or deposit traced, injector removed and assessed where it is the cause, deposits cleared, the seal or component replaced, and dosing pressure verified afterwards. Injector replacement is quoted before it is done.
Why this is not the same job as the other direction
This is an SCR system fault rather than a wrong fill, so the first job is reading the codes rather than guessing at a part. The same dashboard message covers a bottle of fluid and a catalyst.
Common questions
Is white crust around the filler normal?
A little residue after a messy top-up is just dried spill — rinse it off. A crust that keeps returning where you have not spilled anything is a leak.
Does crystallisation damage anything?
Yes. Dried urea attacks aluminium, zinc, copper, brass and mild steel, and at the injector tip it restricts the spray pattern.
Why does it happen more on short journeys?
The system doses and heats on a cycle. Repeated short runs mean it rarely completes one, so residue is left to dry rather than being carried through.
What customers say
4.8 out of 5 from 2,190 Trustpilot reviews. What reviewers mention most is that the technician stayed calm and professional with a driver who was embarrassed and stressed, and that somebody arrived when they said they would.
The most common criticism is price. People do not expect a wrong-fluid job to cost what it costs, and that is a fair complaint to publish rather than bury. The answer is the From just £89 call-out fee, a quote given on the phone before a technician travels, and being told when a job cannot be done at the roadside rather than after somebody has arrived and charged for the visit.
Related AdBlue problems
Start from a symptom instead
Who you are dealing with
AdBlue in Fuel is a service by Forecourt Assist. Forecourt Assist is a trading name of Fuel Fixer Ltd, company no 08520551, registered at Fairway House, Portland Road, East Grinstead, RH19 4ET, a company of Fuel Fixer International. Fuel Fixer International is owned by Stockbridge Capital Holdings.
Reference: Diesel exhaust fluid (Wikipedia).
Across the Fuel Fixer network
AdBlue in Fuel is a service by Forecourt Assist, a brand of Fuel Fixer International, owned by Stockbridge Capital Holdings. The full group directory is at forecourtassist.co.uk/network.