Good AdBlue® is boring to look at. It should be clear and colourless like clean water, with no particles and little or no smell. Most off-spec product looks much the same, which is exactly why problems slip through. Still, there are signs worth knowing, both in the container and in how your vehicles behave.
What to look for in the container
Pour a sample into a clean, clear glass or plastic jar and look at it against a white background in good light. Warning signs include:
- Cloudiness or haze. Good AdBlue is clear. Haze can point to contamination or poor raw materials.
- Colour. A yellow, brown or green tint suggests contamination, often from metals, reused containers or other liquids.
- Particles or sediment. Specks floating or settling at the bottom mean dirt, rust or debris has got in.
- An oily film or sheen. A sign of diesel, oil or hydraulic fluid contamination. Do not use it.
- A strong ammonia smell. AdBlue can have a faint smell, but a sharp ammonia odour suggests the urea has broken down, usually from being stored hot for too long.
- Crystals inside the container. White crystals in a sealed container that don't redissolve once it warms up suggest evaporation or a concentration problem. White crust around caps and nozzles is normal where drips have dried.
Red flags in the supply chain
Sometimes the warning signs aren't in the fluid but in how it reached you:
- No batch number, production date or producer details on the pack
- Broken, missing or re-applied tamper seals
- IBCs that show residue, discolouration or an odour, or that look like they have held another product
- Product that has been stored in full sun, in a hot shipping container or on a roof through summer
- The AdBlue name used by a supplier who can't tell you their VDA licence number
- A price well below what licensed producers charge, with no clear explanation
Our certification page explains what the VDA licence and ISO 22241 involve, and what to ask a supplier for.
What your vehicles might tell you
Vehicles measure AdBlue quality indirectly. Many SCR systems have a quality or concentration sensor in the tank, and all of them monitor NOx downstream of the catalyst. Signs to watch for include:
- AdBlue quality or SCR fault warnings shortly after a top-up
- A drop in engine power (derate or limp mode)
- Blocked SCR filters or injectors found at servicing
- Several vehicles developing similar faults after filling from the same tank or delivery
That last one is the most telling. One truck with an SCR fault could be a sensor. Three trucks from the same depot within a fortnight points to the supply.
What you can and can't test on site
A refractometer is a useful on-site check. It measures urea concentration, so it will pick up AdBlue that has been watered down or concentrated by evaporation. The target is 32.5%, with a spec range of 31.8% to 33.2%.
What a refractometer can't do is detect dissolved contamination. Calcium, magnesium, iron, copper, zinc and other metals are limited to fractions of a part per million under ISO 22241, and they won't show on a refractometer at all. Neither will biuret or aldehydes. A reading of 32.5% only tells you the concentration is right. For anything more, a lab test against ISO 22241-1 is needed.
One thing to do today: take a sample from your bulk tank or IBC outlet into a clean clear jar, label it with the date and batch number, and keep it somewhere cool and dark. If a problem arises later, you'll have a reference sample of what went into your vehicles, which makes it far easier to work out where things went wrong.
If you suspect a problem
- Stop dispensing from that tank or container.
- Keep a sealed sample and record the batch number and delivery date.
- Contact your supplier and ask for the Certificate of Analysis for that batch.
- Check your own equipment for incompatible fittings, dirty hoses or open lids.
- If vehicles are showing faults, tell your workshop what you've found.
How Liquidia can help
Liquidia's AdBlue is made under VDA licence No. 0005569, lab-tested every batch and backed by a 12-month product guarantee, with a Certificate of Analysis on request. Download documents from our resources page or see common questions on the FAQs.