Adblue – The ultimate guide

Buy DEF Diesel Exhaust FluidWhere to buy Adblue?

  • So far, special Adblue (or DEF – Diesel Exhaust Fluid) pumps are only available at a few gas stations. Most of the time, these pumps are suitable solely for trucks. However, at various shops Adblue is also sold in top-up containers and/or bottles (1/2 gallon, 1 gallon, 2.5 gallon).
  • You can buy Adblue in authorized repair shops, and for a fee you can get the refilling done for you.
  • Adblue — like engine oil — is obtainable in every well-sorted automobile specialist shop as well as online: Adblue at Amazon.

How to refill Adblue on your own:

– Audi Adblue Refill

– Volkswagen Adblue Refill

– BMW Adblue Refill

What does Adblue cost?

As with nearly all fluids required for cars (except fuel), you can save money by buying large quantities at the right place. (If you ever had to buy a bootle of freeze-resistant wiper fluid at a freeway gas station then you know about absurd costs.)

Current Costs:

1/2 gallon-refill-bottles cost online about $14.

2.6 gallon-sets are about $25.

How to refill Adblue using the Refill Kit

Can you refill Adblue on your own? Yes, you can!

(Should you find any instruction book that contradicts us, please send a photo for our collection of oddities.)

Refilling Adblue is nearly as simple as topping up the antifreeze mixture for your windshield wiper system. This makes it easy when your automobile persistently requests a top-up in the middle of nowhere.

Depending on the type of your car, there are adapters in your vehicle tool kit that have to be screwed on the filler neck. You will find further information to that in the instruction book of your car. Moreover, whoever refills Adblue on their own can truly save money, as calling the repair shop can get expensive even when the real value of the work and materials is not.

IMPORTANT: Do not put Adblue into the fuel tank!

Adblue has to be poured into the specifically designated Adblue-tank, which has its own filler cap (either next to the normal gas pump nozzles or inside the trunk—please see instruction book)

After topping-up with Adblue, start only the ignition until the on-board computer registers and confirms the refill. This might require a few minutes. Afterwards, start the engine normally. Adblue at Amazon


Audi DEF / Adblue refill

Adblue / DEF filling stations

Unfortunately, there is not yet a web page on which you can search for every Adblue filling station. That is because most Adblue pumps are exclusively for trucks.

Please do not be misled! Whenever you search for Adblue filling stations on the usual gas prize web pages, keep in mind that you will find mostly locations for trucks to top-up with Adblue. To read about the pros and cons of refilling your passenger car’s tank at an Adblue pump for trucks, then click….

For trucks, this overview of Adblue filling stations is already quite good:

Topping up Adblue (with/without adapter)

As there are mostly Adblue filling stations with pumps that are meant for trucks, the question arises:

Is it possible to refill the Adblue tank of an automobile using a pump for trucks?

The answer is yes and no—please read:

– There is a magnet inside of the filler necks for trucks, which is necessary for the cut-off valve in the pump to function. In passenger cars, this magnet is missing. Furthermore, the flow rate of the pumps is adjusted to trucks. Even though you can try to top up Adblue carefully with gentle pressure and without closing the valve, we do not advise that, as it is an annoying waiting game and more likely to result in a mess.

– An Adblue-adapter that can be purchased at a supply store may be a solution. The adapter is equipped with an integrated magnet so that the cut-off valve of the pump can function correctly. However, that is only half the battle:

As the flow rate is too big for passenger cars it is essential to tank up in a very careful and slow manner. That might take between three and fifteen minutes. Nevertheless, Adblue may be spilt.

Another problem—especially with filler necks that are located in the trunk—is the difficulty due to relatively cramped space conditions of reaching the filler necks with the fuel nozzle. This is of course different with a truck: A truck has its tank on the outside and it is therefore easily accessible. For now, we advise our clients to refill Adblue using canisters.

Adblue consumption

The consumption of Adblue is around four to six percent of the normal diesel consumption. A Mercedes S350 Bluetec requires, according to testing, an average of 7.5 liters of diesel and with it around 0.3 to 0.4 liters of Adblue per 100 km.

Driving from Hamburg to Munich on the highway in an S350 Bluetec would therefore be accounted for a consumption of 2.5 to 3.5 liters.

Notification “Adblue is empty”

As soon as the amount of Adblue in your tank runs short, the on-board computer sends a warning and requests refilling. Users also receive a notification detailing how far they can still drive with the remaining amount of Adblue.

If the first message is ignored, users will receive a second, more intense warning that will again share the still remaining number of kilometers they can travel. It will further warn that the car will not restart or will do so with a reduced torque if the tank is not refilled. We urge users to take this seriously, as it is not an idle threat.

Without Adblue the car does not fulfill the required emission and thus is not allowed to drive on or only with a reduced torque. The manufacturers therefore have incorporated an ‘environment-engine-immobilizer’. No starting of the engine (no ordinary functioning) is possible until Adblue is refilled. That is why taking heed of this warning and preferably taking a refill bottle along is strongly advised

Adblue at Amazon

What is Adblue?

Adblue® is a fluid that is required by cars with special, low-emission diesel engine (SCR-system) in order to fulfill the European exhaust emission standards Euro 4, Euro 5 and Euro 6.

Adblue (ISO 22241-1 / AUS 32 / DEF: Diesel Exhaust Fluid) is not poured into the normal fuel tank but into a small, additional tank that is incorporated in the car.

Adblue is the VDA’s (German Association of the Automotive Industry) brand name for a mixture of 32.5 per cent pure urea and purified water.

“Gross!” may be the first reaction to the word “urea”, but do not be misled by the term. After all, there are plenty of people who use safe, hygenic cosmetic products that contain urea on a daily basis.

Is Adblue toxic or dangerous?

Regarding the European chemicals legislation, Adblue does not pose a particular danger.  According to the transport law, Adblue does not count as hazardous goods either. You should nevertheless avoid skin contact and remove potential remnants with water.

How Adblue works

The essential component of Adblue is urea. It is required in cars with diesel engines that are equipped with SCR (selective catalytic reduction) technology. (Actually SCR ammonia would be needed, but this does not only smell unpleasantly, it is further dangerous. That is why the more harmless urea is used, which is only converted to ammonia when necessary). SCR is used by many carmakers, including Audi, BMW, Volkswagen and Mercedes. Most Mercedes cars that display the BlueTEC badge and all Citroen BlueHDi cars use AdBlue in conjunction with SCR technology.

With the aid of Adblue, the ecologically harmful nitric oxide (NOx), which is present in exhaust fumes, is selectively converted to water and nitrogen, without the emergence of undesirable byproducts.

The exact dose of Adblue/urea during the waste gas treatment is regulated by a control module, which analyses the exhaust fumes with the help of a nitric oxide sensor.

Does Adblue freeze in wintertime?

Yes, Adblue freezes at temperatures below -11 degrees C. Freezing will not change its efficiency nor concentration; it can therefore be thawed and utilized without any problems.

If you take a longer car drive in freezing temperatures, make sure that the Adblue to refill your tank is not frozen.

Your engine will not start again as soon as the tank runs out of Adblue (see), and you will therefore need to have more, not frozen Adblue in a refill bottle.

The system in your car as well as the system at filling stations is heated. Temperatures below zero are therefore only problematic when you want to use canisters or bottles to refill.

Alternatives to Adblue

According to the VDA it is inadvisable to use any product called “urea solution” or suchlike, which does not carry an official lettering that says Adblue.

Although it is tempting to try to find cheaper alternatives to a brand name, the VDA strongly discourages this for a variety of safety reasons

Adblue is widely affordable, and it rather helps to reduce diesel usage. With Adblue, an ordinary waste-gas recirculation, which normally increases the consumption of diesel, is not necessary anymore.

Using an alternative may damage a vehicle’s engine, steering system, or SCR technology. Using substitutes that have not been approved may weaken the users position with the automobile manufacturer in issues connected to warranties and more.

We advise users to look to save money elsewhere.

Cars with Adblue technology

Automobile manufacturers use different names for the after-treatment of exhaust gases with urea (SCR). However, they do have the usage of the word “BLUE” in common:

Some Volkswagen Bluemotion models (e.g. Golf, Jetta, Passat, Sharan, Touran) use SCR technology with Adblue

Blue Performance with SCR e.g.
BMW 5er Limousine: 520d xDrive, 525d xDrive, 530d xDrive, 535d xDrive
BMW 5er Touring: 520d xDrive, 525d xDrive, 530d xDrive, 535d xDrive
BMW 5er Gran Turismo: 520d, 530d xDrive ,535d xDrive
BMW X5: sDrive25d, xDrive25d, xDrive30d, xDrive40d, xDrive50d

e.g. E350, G350, GL 350 4Matic, GLK 220 GLK 250, ML250, 4Matic, ML350 4Matic, S350

Citroen BlueHDi

Audi TDI Clean Diesel

Opel „BlueInjection“-SCR-Technology

Peugeot BlueHDi

SEAT Scr-System
(e.g.Seat Alhambra)


AdBlue® is the registered trademark of Verband der Automobilindustrie (VDA)

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