DEF how old is too old?

[VinnyP]

I have an opened jug of DEF dated July 2019. Can't tell if that is a manufactured date or an expiration date. Any ideas? Or should I just breakdown, dump it and buy a fresh jug?

[Cummins12V98]

Learjet wrote:

Cummins12V98 wrote:
If stored in a cool place it’s most likely fine. Personally I would not use it. I on
only buy what I need.

Wow! took several responses before someone mentioned the most important thing....what was the temperature it was stored....that is the most important factor.

Johnny, tell us what I won???!!!

[Learjet]

Cummins12V98 wrote:
If stored in a cool place it’s most likely fine. Personally I would not use it. I on
only buy what I need.

Wow! took several responses before someone mentioned the most important thing....what was the temperature it was stored....that is the most important factor.

[otrfun]

DEF's shelf life varies by temperature:

<50 deg, ~36 mo.
50-77 deg, ~18 mo.
78-86 deg, ~12 mo.
87-95 ~6 mo.
96-104 ~2 mo.

If you live in southern AZ probably should refill with limited amounts of DEF unless you drive a lot.

[Lynnmor]

I would question the age of the DEF that is already in the truck, perhaps the DEF in the jug is better.

[dodge_guy]

Dump it. Def has a shelf life. If it's stored in a cool place out of sun it's good for 12 months. If it's stored in direct sunlight then 3 months.
The key is in how it's stored.

[BurbMan]

Having just bought my first diesel, I'm new to this DEF stuff and you got me wondering. Here's how to read the date code on Peak Blue DEF



Note that the year noted is the Expiration year, the year of manufacture is actually one year prior. So if your DEF is showing 2019, it was actually made in 2018 and is DEFinitely too old to use. 🙂

[2oldman]

From google:

"Storing DEF in a cool, dry, well-ventilated place is recommended to maximize shelf life. It will degrade over time, but if stored at temps between 10 degrees and 90 degrees, DEF has an expected shelf life of one year. You can extend the shelf life to two years by storing at a temperature that stays around 75 degrees."

[Cummins12V98]

If stored in a cool place it’s most likely fine. Personally I would not use it. I only buy what I need.

[VinnyP]

Sounds like I’ll dump it and get a fresh jug. Thanks everyone!

[stickdog]

I would dump it. It would work good as fertilizer but would want to water it down as it's 33% urea which could burn whatever you dump it on.

[RobWNY]

From what I've read, DEF gets "iffy" after 18-24 months. Is that date of July 2019 from a Blue DEF code? If so, it was actually made in July of 2018.

[Grit_dog]

NRALIFR wrote:
It’s probably OK, but you can get on Amazon and buy an inexpensive refractometer that will tell you if it still has the correct 32.5% urea. Some refractometers can also check multiple fluids, like antifreeze, windshield washer fluid, DEF, and battery acid.

:):)

And for only the cost of 2 NEW jugs of DEF or probably 6+ gallons at the pump you could buy a device to "check" it....
How is this even a question or a thread?

(BTW NRA, you're correct, but you just got over the OP's head, mechanically speaking. He's best off parting with an Alex Hamilton and a couple of G Dubs for some fresh DEF...)

[Grit_dog]

VinnyP wrote:
Any ideas? Or should I just breakdown, dump it and buy a fresh jug?

Pheww, quite the quandry here. You have an expensive truck that presumably is worth alot of money becasue it's fairly new, diesel, and likely doesn't get driven much.
Now you have a partial jug that you didn't manage to use in the last year or so and how long will that DEF sit in your truck?

Bottom line don't be a cheap ___ and save yourself potential/likely future headaches at the expense of spending 10 whole dollars on your truck.

[NRALIFR]

It’s probably OK, but you can get on Amazon and buy an inexpensive refractometer that will tell you if it still has the correct 32.5% urea. Some refractometers can also check multiple fluids, like antifreeze, windshield washer fluid, DEF, and battery acid.

:):)