AdBlue (urea additive)
 

Hello diesel drivers,
Newbie Tenderfoot here, with a question for the forum. Has anyone had any experience with running low or even out of the urea "adBlue" additive on their "clean diesel " TDi powered car? My owners Manuel suggests my engine will not start or run if I deplete the adBlue injection system. There is no way to determine how much is left in the system, and I am planning a trip west through some desolated areas. The last thing I want to worry about is to throw a code due to running out of urea, and shutting the system down. Should I carry an emergency supply's? How can I determine if I am running low?
Anyone have an experience they want share? Comments?
Thanks for your suggestions.
Tenderfoot and comfort too!

You can buy a gallon of it at Wal-Mart and keep it in the trunk if you're that worried about it, but I believe that tank is supposed to be topped off as part of the regular oil change service.

How come you have to add Urea? Ive never heard of this practice before.

The urea(DEF) is needed as an reactant to reduce NOx levels down to EPA regulations. Not all diesels use it, but other methods tend to give up fuel economy.

The vehicle will give plenty of warnings to it running low on DEF. Even if it runs out, it won't simply die and strand you. It will keep running until the engine shuts off. Next start up will be in a limp mode with a top speed of 25 to 35mph. You won't get stranded in a desert.

As Jay states, a tank of DEF should last to the next oil change at least. If you are getting close to an oil change, just add some DEF before your trip.

That seems a bit of an old fashioned way of redicing emissions, surely there's a more modern way? Reminds me of adding a lead replacement for old fashioned cars that used to run on leaded fuel.

Remember though, this is an Audi diesel, the oil changes are probably 30,000 miles or 2 years so be careful what you recomend.

Thanks guys, the thought of running out and limping in from northern Utah or New Mexico to the closest Audi dealer (100-200miles?) was a little disturbing. I know diesel fuel is available all over, but "adBlue" was
bothersome. Yes, the dealer does top off at oil change, but a little double checking on my part is reassuring. I might just carry a gallon in the back when we head out to the wild, Wild West.
Tenderfoot

Just checked the oil change intervals for your car, the US service schedule says you should change the oil every 25,000 for that engine, so bear that in mind ;)

This is the modern way of reducing emissions while not sacrificing performance or fuel economy. The EPA and CARB limits for NOx are tighter than Euro6 for both diesel and gasoline cars. NOx limits for Euro6 is 0.08g/km and 0.06g/km for diesel and gas. One of the hurdles to diesels in the US is the fact that they have to meet the same limits as gas which is 0.0311g/km.

It doesn't look like much difference on paper, but it is enough that cars that can pass Euro6 can't pass EPA. The Mazda6 diesel has been delayed for over year because of it. They don't want to use a SCR(urea) system for the US market, but getting the engine to pass without it means losing performance and/or fuel economy to the point that it is uncompetitive with their gas models. Honda backed out of bringing their diesels over around 2005 for the same reasons.

https://www.dieselnet.com/standards/eu/ld.php
https://www.epa.gov/otaq/standards/li.../tier2stds.htm

The DEF tanks are around 7 gallons, maybe 10g on a truck, and only small amounts are used. Auto parts stores, gas stations with diesel, and Wal-mart carry it in in jugs or 2.5gal boxes. Truck stops will have a pump dispenser of it. Probably right next to the truck diesel pump.

Thats what I don't get, there might be very few diesels sold in the US, but that doesn't mean there arent any. Even those that are sold seem pretry big, 2.0L, 3.0L etc and they dont seem to be the "eco" versions you get here either (strange because the emissions are lower to begin with) So what are they doing to get the ones on sale to pass?

The other thing is, I see CAFE want to reach an average of some 50 MPG in the near future, and reduce C02 aswell. That means a lot of diesels are going to need to be sold, cant see any way around it unless the US market is going to flooded with gas/electric hybrids?

According to Wikipedia, diesels with the DEF system use around 2% to 6% of the volume of diesel fuel. So for every hundred gallons of diesel you would use somewhere around 2 to 6 gallons of DEF. I have noticed, without paying any particular attention to it, many truck stops with signs saying "DEF at every pump." Just another expense for Diesel drivers.