DEF (Diesel Exhaust Fluid) is DEF, right?

[Best4x4xFAR]

First, this has probably been covered, and if so I apologize, but my search skills must be letting me down. I found a lot of discussions on fluid usage, but not much on this specific question..

So the first time the DEF 'No Start' message came up, I purchased BMW DEF Fluid for the refill. But is it really any different than Peak or Shell or any number of other brands of DEF fluid?

Manual of course 'recommends' BMW DEF fluid, saying, "Preferred: BMW Diesel Exhaust Fluid." but then goes on to say, "Alternative: NOx reduction agent AUS 32"

BMW of course can't require you to use their fluid, unless they are willing to supply it free of charge..

So is there really any advantage to paying roughly twice as much for the BMW branded fluid over a fluid that carries the 'AUS32' rating?

I don't mind purchasing the BMW fluid online from FCP Euro or other, but the Peak and Shell DEF fluids are readily available at almost every store, and are a bit less than half the price. If its really all the same stuff, why bother?

That brings me to the other question, shelf life. Seems like I hear the 'one year' life mentioned a lot, but is that for a sealed unused container, or only apply after it is opened?

Appears that the DEF fluids available in local stores have manufacture dates, but not expiration dates. Shell states a two year shelf life on average for this product, but notes it is dependent on storage location/temperatures..

All of this makes me think its best to let the system run down to the no start warning before refilling, in order to keep fresh fluid in the system, instead of topping off opportunistically, to avoid getting the no start message.

Furthermore, BMW dealers get this stuff in bulk. And I don't think they have a lot of Diesel vehicles coming through the department. So should you be worried about the dealer's supply going stale if you're getting the 'free top-off' with service?

Okay that was more than I intended, sorry..

[Nyc Dito]

Originally Posted by Best4x4xFAR

So the first time the DEF 'No Start' message came up, I purchased BMW DEF Fluid for the refill. But is it really any different than Peak or Shell or any number of other brands of DEF fluid?

I bought a "Bluesky" brand 2.5 gallon jug, but also a VW 1.89l bottle that I can remove the cap and refill from that bottle into my passive tank.


As far as I know, its the specs that matter. BMW suggests a drain and refill, but I just bought the E70 in February so I might do it after a full year of ownership.


BMW will always or usually suggest BMW branded fluids. I'm surprised we haven't seen a BMW branded fuel station yet!

[josiahg52]

I'll have to look but the 2.5 gallon carboy of BMW fluid is really, really cheap. $20 I think at my dealer so that's where I get mine. My dealer has given me a five gallon carboy on the house in the past.

I saw a substantial decrease in miles between 'No Start' warnings from 11-13000 miles to just over 8000 miles when I tried Peak and AdBlue DEF. The actual consumption rate depends on a lot of factors but I didn't feel like I was saving anything so now I use BMW DEF only.

I know the 'No Start' warning occurs every 11-13000 miles if I let it go so now I top it off every oil change which is every 8-9000 miles and know I can go further if I need to.

[ard]

def is def


Ive used BMW (5 gal happened to show up in the back of my car once...), ive used home depot brand....

[MillerMav]

I had good luck in the past with Peak which I switched too after using BMW for quite a while. If you live near a BMW dealership the 5 gallon BMW DEF is cheap so I would just stick with it. If you don't then go with Peak. I bought some off brand DEF jug at the local O'Reilly's and within a few hundred miles my DPF was clogged and my X5 was undrivable. Now, this lead to me doing a full delete which was awesome and cheaper than replacing the DPF but still, with my new X5 I did my first fill with BMW (to get the trick bottle) but will go with Peak until I do the delete next spring-ish time frame.

[ard]

Hey, someone should start a branded DEF company.


Some german/euro sounding name. Toss an umlaut in the name. Make some performance claims, better mileage....maybe 'green too'.... Buy the peak stuff, rebox it with M///stripes....



Pay a few shills here and on other forums to talk it up, fake reviews and claims. Cut the mods in for some action and they could keep honest folks off you back.




Sounds like a plan, eh?