DEF fluid expiration?

[two_travelers]

We have a 2023 Winnebago View on the Sprinter chassis. Currently have about 1/2 tank of DEF and plan to top off before storing for the winter. I have some DEF in the basement with a manufacture date of May. Is it safe to use this or should I buy fresh? We will likely use the coach again in March next year. From what I've read it might be OK but would like some real world opinions.

[way2roll]

ScottG wrote:

way2roll wrote:

dalej wrote:

ScottG wrote:
One thing is for sure, you do not want to put bad DEF in it.

This

What happens? Do you have an example of using "bad" DEF? And how do you tell if it's bad?

I have read of plenty. If bad, it can clog the injector, cause pump failure, damage the DEF quality sensor and and in some cases require the entire tank assembly (with pump, sensor) be replaced. It can quickly climb in to the thousands to repair.

Care to share the links for these accounts?

I've read a lot of the opposite. On a few diesel forums there are accounts of guys running plain water in their DEF tanks when they run out. Worst case was a "bad Def" code and went in to limp mode. Many say nothing happened at all. The DEF system is not much more than a pump with an atomizer that sprays a mixture of urea and water. Sans a few sensors, it doesn't affect the engine at all.

Back on topic, different brands and sources all cite different shelf life and potential issues. Seems very ambiguous.

To the OP, if you are worried about shelf life, aren't you concerned about the age of the DEF that's already in the RV when you put it away for storage?

Personally I'd top it off before putting it away, or leave it and add new in the spring. I don't think it will matter a bit either way. I think this is a case of a solution in search of a problem.

[enblethen]

I don't use DEF, however it seems to have different storage and use between sources.
That means there must be different quality or ingredients.
Has anyone done research?

[ScottG]

way2roll wrote:

dalej wrote:

ScottG wrote:
One thing is for sure, you do not want to put bad DEF in it.

This

What happens? Do you have an example of using "bad" DEF? And how do you tell if it's bad?

I have read of plenty. If bad, it can clog the injector, cause pump failure, damage the DEF quality sensor and and in some cases require the entire tank assembly (with pump, sensor) be replaced. It can quickly climb in to the thousands to repair.

[bobndot]

eHoefler wrote:
What till spring and top off with very fresh DEF.

X2.
Reason : winter temps in ny. Store the new stuff in warm indoors.

From DEF website .
“Like many products on the market today, Blue Def does have a limited shelf life. But its shelf life is determined by the ambient temperature it is stored at and not its ingredients. To have a 3 year shelf life, Blue Def must be stored at temperatures no higher than 50 degrees F.”

[mike-uswest]

ScottG wrote:
One thing is for sure, you do not want to put bad DEF in it.

I liked it a lot better when I didn't have to use any DEF.

[way2roll]

dalej wrote:

ScottG wrote:
One thing is for sure, you do not want to put bad DEF in it.

This

What happens? Do you have an example of using "bad" DEF? And how do you tell if it's bad?

[dalej]

ScottG wrote:
One thing is for sure, you do not want to put bad DEF in it.

This

[way2roll]

I know the manufacturers say it has a shelf life, of course they want you to buy more DEF. But I have never heard of any actual issues with someone using old DEF. Lots of theories and warnings but I have never read of a documented case. It's urea and water and gets atomized into the exhaust. And are you going to drain the DEF in your tank in the spring? Isn't it probably just as old?

[eHoefler]

What till spring and top off with very fresh DEF.

[ScottG]

One thing is for sure, you do not want to put bad DEF in it.

[Grit_dog]

It’s not gasoline, so the topping off theory (also flawed when considering gasoline) does not apply.

[enblethen]

From DEF facts

16. What is the shelf life of DEF?
If the DEF is stored at ambient temperatures of 75 F with no major periods of exposure to heat over 86 F 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.

[Trackrig]

All sorts of people are going to leave it sitting in their equipment that will sit idle for at least the winter. Farmers, dirt people, truckers, etc.

Bill