Adblue, what is it?
Adblue is a liquid that consists of 32.5 percent urea solution and 67.5 percent demineralised water. Adblue is produced by the chemical reaction of ammonia and carbon dioxide. Around one kilo of natural gas is needed to produce one litre of Adblue.
Adblue is used for exhaust gas aftertreatment. The use of Adblue can reduce nitrogen oxide (NOx) emissions from a diesel engine by up to 90 per cent. This makes the aqueous urea solution an effective means of combating high nitrogen oxide emissions in road traffic.
How does Adblue reduce nitrogen oxide emissions?
Adblue is always used in conjunction with an SCR catalytic converter. In this SCR catalytic converter, nitrogen oxides are converted into harmless nitrogen and water vapour. And this chemical conversion works with the help of the urea solution Adblue. While the engine is running, the Adblue is injected into the exhaust gas flow. This produces ammonia, which in turn reacts with the nitrogen oxides from the exhaust gases. This produces nitrogen and water vapour.
Adblue: How high is the consumption?
The amount of Adblue injected varies depending on the load status of the engine. If the engine is running at full speed (for example, because you are driving particularly fast or crossing an Alpine pass at high revs), the SCR catalytic converter requires more Adblue. On average, Adblue consumption amounts to around three to five per cent of fuel consumption.
According to Fiat, Adblue consumption is around 5 litres per 1,000 km, but varies according to driving style. The tank capacity is approx. 19 litres. We recommend that you keep an eye on the mileage or make a note of it. You should also carry a 5 litre Adblue canister as a reserve for safety reasons.
When the Adblue tank is full, the messages should appear depending on the driving style:
- 14 litres approx. 1,000 km driven
- 9 litres approx. 2,000 km driven
- 4 litres approx. 3,000 km driven - top up
If the AdBlue indicator lights up permanently, this is a problem with the base vehicle. Only the base vehicle manufacturer can help you with this.
Is Adblue relevant for campers?
If you tow a caravan with a diesel car, you may already be familiar with the use of Adblue. Adblue has hardly been an issue for motorhome owners until now. With a market share of just under 50 per cent, the Fiat Ducato is the most popular base vehicle among motorhomes. The Fiat Ducato has only been equipped with Adblue injection since the 2020 model year. Without the exhaust gas purification system, the current Ducato would no longer have received Euro 6 d-Temp approval. Newer motorhomes based on Citroen, Peugeot, Mercedes, Renault and VW/MAN also have an Adblue tank.
Do I have to use Adblue at all?
Yes, because once the Adblue tank is empty, the engine can no longer be started. This is not so much a technical issue as a legal requirement in the context of environmental protection. This is why the engine manufacturers have installed a corresponding switch-off device. If the Adblue level is low, an indicator light warns you in good time. The first warning often appears when the remaining range is 2,000 kilometres. In some vehicles, a message also appears in text form on the on-board computer, sometimes indicating the quantity to be topped up.
Are there any disadvantages to using Adblue?
Adblue does not have any negative effects. At most, the maintenance costs of the vehicle are slightly higher with Adblue. If necessary, you will need to buy and top up the liquid. Depending on the mileage, this may be necessary once every six months. Cars and motorhomes with Adblue injection achieve correspondingly low nitrogen oxide values and can be driven with a green sticker.
Adblue sucks! If some of the acid drips onto the paint, it should be washed off immediately with water.
Where and in what form can I buy Adblue?
Adblue is sold at petrol stations, garages and also in larger supermarkets and DIY stores. Adblue is available there in plastic canisters containing five or ten litres. Make sure that the canister is supplied with a filling aid in the form of a flexible hose. This is because the opening of the filler pipe is standardised and the precisely fitting hose prevents any of the liquid from spilling out.
Some petrol stations also have pumps for Adblue. You can fill the liquid there in a similar way to the diesel pump. But be careful: most Adblue pumps are only suitable for lorries. To date, there are only a few Adblue pumps that are approved for refuelling cars. You can find out whether you can refuel your motorhome with Adblue at a truck fuel pump in your vehicle's user manual.
Are there differences in the quality of Adblue?
If it says Adblue on it, it has Adblue in it. Like diesel or petrol, the urea solution is subject to strict quality criteria. If the Adblue logo or a reference to the ISO 22241 standard can be found on the petrol pumps or canisters, you can safely fill the liquid into the filler pipe provided for this purpose.
Is Adblue also available abroad?
Adblue is also available in other European countries. Vehicles with Adblue injection are not only widespread in Germany; motorhomes and trucks with SCR catalytic converters are also on the road in many countries. However, the supply of Adblue pumps in some countries is not as dense as in Germany, for example. By way of comparison, there are around 500 petrol stations in Germany with Adblue dispensing systems. In France, on the other hand, there are only 150 such petrol stations, while in Switzerland and Spain the number is only in double figures.
Where do I fill up with Adblue?
Good to know: the colour of the screw cap is always blue, whereas the diesel tank has a black cap. The position of the Adblue filler pipe, on the other hand, is not standardised. In motorhomes, the filler pipe is often located below the filler opening for the diesel tank. In the case of Fiat, Citroen and Peugeot, both openings are located under the same metal panelling, whereas Ford gives each filler opening its own flap. For Mercedes-based motorhomes, you must open the bonnet. Here, the Adblue opening is directly adjacent to the right-hand headlights.
Special case A Class: in this case, the Adblue may have to be filled in the cab. This solution is less practical, especially if something goes wrong when refilling.
Can Adblue be retrofitted to older vehicles?
Yes, retrofit systems are available. Manufacturers such as Dr Pley, Oberland-Mangold and HJS offer SCR systems with Adblue injection for retrofitting to various makes. The costs are between 2,000 and 3,000 Euro, depending on the system. HJS already offers retrofit systems for the Fiat Ducato and VW T5, which are popular with campers. It is important that the desired retrofit system is approved by the Federal Motor Transport Authority (KBA) and has a general operating licence (TA).
In certain cases, vehicle owners can benefit from a subsidy when retrofitting an SCR system. However, financial support is primarily only available for commercially used vans and tradesmen's vehicles. If the vehicle is a motorhome, no subsidy is possible according to the HJS company. The full costs are borne by the vehicle owner, who is then allowed to drive the converted motorhome in city centres with a green environmental zone.
Conclusion: Adblue is easy to maintain
If you own a vehicle with an Adblue tank for the first time, not much changes in practice. The additional maintenance effort is extremely low. On average, Adblue needs to be refuelled once every six months. The costs are also kept within limits. Adblue tank and SCR catalytic converter is no reason to postpone the decision for a new motorhome.