How to beat the Sprinter blues "AdBlue"

There are many confusing info circulating the net about DEF fluids, brands to use, etc. Some Sprinter owners have been told by MB dealers to only use an MB branded DEF fluid "AdBlue" on their Sprinters or the DEF system could malfunction.

The truth is, if the DEF fluid is ISO-22241 certified then it is ok to use as per Sprinter operating manual. I've been using "BlueDEF" brand from my local auto parts store for many years without any problems. 

When my Sprinter NOx sensor went south a few years ago, MB dealer even tested the "BlueDEF" branded fluids in my tank and it passed to their standards, no surprise there. I'm not claiming I'm a DEF expert, just a user trying to save a buck from overpriced MB pee (ok, it's not actually a pee but rather it's a combination of 67.5% deionized water and 32.5% urea.)

Okay enough with the ramblings, here is what I do to make sure I don't get a bad DEF fluid in my Sprinter. A bad DEF, you asked? Yes, DEF is regulated and ISO certified, but anything could happen after leaving the factory. 

1.    DEF has shelf life. If the DEF is stored at ambient temperatures of 75ºF with no major periods of exposure to heat over 86ºF then the batch of DEF will last roughly two years. If a package of DEF is exposed to periods of heating the fluid will last approximately one year. 

• Don't pick the DEF boxes that are stored next to the store windows and are exposed to direct sunlight.
• If you don’t drive your RV much, drain and refill the DEF tank every 2 years.
• Pick the latest production batches of DEF. Check the DEF box for a date code: Example,
  "BlueDEF" brand uses something like GA203590089. To decipher the date code, see below.
  The date code breaks down to 4 groups of numbers as follows:
  GA: The designator of the plant that manufactured the DEF
  20: The year of manufacture -1, so this DEF was made in 2019
  359: 365-359 = 6, so the 6th day of the year, or January 6th.
  0089: The batch code. So this DEF example (GA203590089) was made on January 6, 2019.

 2.    The DEF can be contaminated. I’ve read it somewhere that some really bad people will buy a container of DEF then replaces the DEF with water and returns it back to the store for a full refund. 

• Check the container seal, if it’s broken or looks tampered with, don’t use and return it.
• Check the DEF quality using a refractometer. I’ve been using this inexpensive gadget and it actually saved me one time from possible expensive repair. Sometime last year, I bought a 2.5 gallon container of DEF, when I opened the container cap, the mouth seal was almost too easy to peel off which was unusual, so I tested it with my refractometer…low and behold I got a 10% Urea reading.

      Refractometer I use: DEF REFRACTOMETER  $25

      Disposable pipettes for extracting DEF sample from container

      (to prevent cross contamination): 

                                        200 pc. DISPOSABLE PIPETTES $8.25

3.   I always top off the DEF tank. I have no scientific data to backup the claim here, this is just my own opinion and observation. Here is what I think why you should, when you let the DEF fluid low in the tank, DEF slushing in the tank when driving especially in really cold weather can possibly over expose the DEF heater element to air while it’s active and could possible shorten it's service life. The DEF pump also possibly benefits from always full fluid level to help dissipate heat. Shoot me a comment of what you think. Happy Trekking.