DEF Fluid Life

[Ultrarex09]

Looking at purchasing a 2017 Newmar On a freight liner chassis from a private party.It has a isb6.7L.
It’s a 360 hp. It had the majority of the 3400 miles during the first year. The last 4 years been parked mostly. There has not been any def added to tank last 3-4 years. It’s 1/2 full. I drove it several miles runs great no warning lights. Thoughts on damaging the engine operating it this way?
Thanks
Rex

[pasdad1]

I would siphon all the DEF out of the tank and refill with new fresh DEF.

[Ray,IN]

Blue Sky DEF information page: https://blueskydefna.com/know-the-sh...exhaust-fluid/

From reading the article, if DEF changes color it must be replaced regardless of age.
Then this pdf from motorcraft.com: https://www.motorcraft.com/content/d...%20Quality.pdf


And Cumminsfiltration.com:https://www.cumminsfiltration.com/si...es/MB10033.pdf

[NevadaNick]

Bad def will not damage the engine and the fact that you drove it and eveything was fine should tell you its ok. If it was me i would top off the def and enjoy the ride.

[Archer2]

NevadaNick is correct that out-of-spec DEF will not harm your engine, mainly because DEF never gets near your engine. The DEF is injected into the exhaust stream after the Diesel Particulate Filter.
BUT starting in 2016 the EPA began requiring the manufacturers to install a sensor to monitor the quality of DEF and if it strays too far from the ideal of 32.5% Urea the EPA requires the engine to be derated beginning almost immediately and increasing in severity until the coach is limited to 5MPH unlike the problem is corrected.
This summer I ran a test. I filled my DEF tank with fresh fluid in early May, drove it from AZ to AL where it was parked in temperatures of 90+ Until late August and I measured the fluid with a refractometer every week. The reading stayed steady at 32.5% until the very last week of August then it dropped to 31.5% in one week. Cummins has said that the limits are +/- 0.7% so I drained it and refilled with fresh fluid. While I hated to dump the 8 gallons or so of fluid because it was expensive, it just wasn’t worth the hassle of having a problem on the road. Apparently DEF goes bad very slowly and then all at once.
So my recommendation is if in doubt measure it and if it isn’t 32.5% urea then replace it. If you can’t measure it then replace it anyway proactively.

[Toribk]

I would err to the side of caution and siphon out all the old DEF in the tank and change the DEF dosing filter as well.

[Jmac00]

DEF degrades faster with higher temps, if you can keep the DEF in the 45 to 75° temp range, the DEF could last a couple years.

When DEF gets in to 80° plus range and higher, for a long period of time the faster the stuff degrades.

Three or four years?? I'd be dumping whats there and replace with fresh stuff

[Ultrarex09]

Thanks everyone for your input. If I get the coach I will
Remove the old and filter also. Add all new.
Thanks again,
Rex

[Archer2]

Changing the fluid is wise but I’m not so sure that changing the filter is necessary. I think the only problems that you could have that would be the fault of the filter would be a restriction of flow and corresponding low DEF pressure but that would depend on how much DEF it has had run through it. That’s assuming that the filter has not physically deteriorated and fallen apart from age.
Even if the filter contained a tiny amount of out of spec fluid it wouldn’t cause any problem at all.

[wagonmaster2]

Where or how do you get rid of the old DEF after draining the tank? Couple years ago I drained about 5-6 gallon of what I thought might be old DEF from setting 2 years through lack of travel due to Covid and thought since Eura is good fertalizer I sprayed some over spots in the back yard. Wrong. Too strong and burnt a couple patches about 5'x6'.

Now wondering how to get rid of it if task comes up again.

[dbircky]

Originally Posted by wagonmaster2

Where or how do you get rid of the old DEF after draining the tank? Couple years ago I drained about 5-6 gallon of what I thought might be old DEF from setting 2 years through lack of travel due to Covid and thought since Eura is good fertalizer I sprayed some over spots in the back yard. Wrong. Too strong and burnt a couple patches about 5'x6'.

Now wondering how to get rid of it if task comes up again.

Pour it down the drain. It’s urea and water. Same stuff as the millions of gallons flushed everyday.

[Archer2]

If you want to use it for fertilizer instead of pouring it down the storm sewer, the urea concentration for fertilizer by weight is 0.5% to 2%. The automotive stuff is 32.5% urea. So just dilute it by adding somewhere between 16.5 to 65 gallons of water per gallon of automotive DEF. I don’t know if it would be worth the trouble but it’s doable.

[wagonmaster2]

Understand, thank you. would be a lot of trouble deluting 5-10 gallons of DEF to spread on yard.