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Author Topic: DEF  (Read 396 times)


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« on: November 05, 2017, 04:48:13 AM »
Recently I discovered that DEF  has an expiration after a year, question is does this mean it will go stale in the tank if not in use if it does what does it mean to the system, or is there an additive you can put in it to refresh it or whatever?
I'm sure it's disgust in here somewhere it's just easier to re ask.


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« Reply #1 on: November 05, 2017, 08:32:26 AM »
The quality degradation varies greatly with temperature.  It is a good idea to not buy excessive amounts, store in a cool place and only add when the DEF tank is rather low.  There are no additives that I am aware of.

Gary RV_Wizard

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« Reply #2 on: November 05, 2017, 08:49:50 AM »
It's probably not anything you need to be concerned about in the vehicle tank, but avoid buying large quantities that would need long term storage, especially in hot weather. You probably don't want to take advantage of DEF by-the-55-gallon-drum pricing.
Gary Brinck
Summers: Black Mountain, NC
Home: Ocala National Forest, FL