Originally Posted by BandJCarm
Why is DEF fluid dated on the carton, then???
I'm pretty sure after the last 8 years it's a regulation. Over 29000 new ones since 2008. It's prolly in there somewhere.
Here's Google on the issue
A date code, or expiration date can be found on just about any package of DEF. This is called out in the specification for DEF: ISO 22241.
Most DEF manufacturers are certified by the API. The API is the American Petroleum Institute and it has a voluntary certification program for DEF. The API offers (sells) manufacturers rights the API mark. Your owner's manual probably requires you to use DEF that is per the ISO 22241 specification, and that has this API marking.
Here is the secret to reading the expiration date on BlueDEF manufactured by Old World Industries LLC and sold under the PEAK Brand. Other manufacturers differ. I'm working on a complete library of date codes.
This BlueDEF information is from an email reply from PEAK Technical Services dated July 1, 2013 in response to my request for how to read the date code (after having a big leak problem with some old jugs I purchased at an auto parts store).
"The most important part of the batch code is the third through seventh numbers. There are always going to be two letters or numbers at the beginning of the code, which is the blending facility code, The third and fourth number of the code is the year +1. The fifth, sixth and seventh numbers of the code are the days left in the year, or reverse Julian date. So if the code says 257 for example, that would mean it was made on the 108th day of the year.. April 18th."
The date code on the BlueDEF box in my picture is
Lets break this down into 4 groups of numbers:
GA: The designator of the plant that manufactured the DEF
15: The year of manufacture plus 1, so this DEF was made in 2014
359: 365-359 = 6, so the 6th day of the year, or January 6th.
0089: The batch code.
So this box of DEF was made January 6th, 2014.
Specification life for DEF is 2 years at 75F or so. Stored properly, this DEF is good thru January 6th, 2016 (and probably longer).
Storage life is highly dependent on temperature. DEF stored at 85F only lasts 12 months. Storage above 95F (not unusual in an vehicle parked in the sun during the summer) is limited to 1 month or so. Reason: The urea in DEF decomposes and creates ammonia liquid and vapor in the jug, causing issues when you open it, and reducing the amount of urea in the DEF when it is used in the vehicle. Storage above 95F requires retest of the DEF prior to use (source: ISO 22241-3, most recent revision).
Tip #1: Don't buy old DEF jugs. When buying DEF in jugs, look at the code. In 2014, find a jug with 14 or 15 in the 3rd and 4th spaces and the highest three digit number you can find in the 5th, 6th, and 7th digits. Store it in a cool location out of the sunlight.
Tip#2: Buy DEF from stores that are likely move a lot on inventory, have controls on inventory age, and are air conditioned. Not that it is a guarantee, but big name outfits are likely a good bet.
Tip#3: DON'T buy jugs of DEF at a gas station that stores them outside, or have obvious signs of degradation like leaks, crystals on the box or jug, or are off color.
Tip#4: Keep your receipts for DEF in case there is an issue.