DEF Shows low def

[jagpot]

AlertJust went off so we pulled over on the side of the road it says low DEF we just had a filter changed we checked it there’s half in the container the bars I’ll say all four the alarm won’t go off any suggestions?

 

[Neal]

It sounds like what @ARD just reported.

OTR Diagnostics, DEF, Derate Faults

So it's been a fun few days (cough). As I was driving up a mountain pass, my check engine light and alarm went off. With nowhere to pull over, I stopped in the slow lane and called Spartan. I had 3 DEF faults and found out later I had a 4th, an engine torque derate fault. As I was 30 miles from...

rvforums.com

 

[Old-RV'er]

Hmmmm, like the 3rd or 4th DEF issue. If using diesel truck stop def, I think I would stop and buy the Blue DEF 2.5 gallon jugs and fill from those. Who knows what is going into the tanks in this day and age. Suspect some bad/contaminated def at fuel stops, without analysis, who knows, better safe than sorry. Hope you get issue taken care of.

 

[VernV]

The float in the tank will get crud on it's guide from being exposed to the air. That keeps the float from moving up with the tank level. Try keeping the tank completely full all the time and it may dissolve the gunk. My local truck repair shop says that this among a rash of other DEF issues is very common. He has a mechanic pull the header off the tank and remove the buildup on the float guide.
Vern

 

[Richpatty]

Yea…I have heard of this…but I have not been able to travel as much in the last year or so and am not using up DEF, and don’t want it to age out in the warm weather so I have been putting in DEF only as needed. So what is the balance of keeping a full tank but avoid having old DEF? Is there a way to easily drain the tank?

 

[Neal]

It doesn't pass the common sense test to me. Someone needs to get with a vendor and find out the real story on how a DEF tank is designed and works. It seems to me the tank should be able to function down to completely empty and read tank levels as such. We are all trying to engineer something we no little of but all seem to speculate heavily about. Same with DEF sources when I have a feeling the Spartan/Shaw DEF issues are completely unrelated to the actual DEF in any way but is completely a computer issue (circuit board, sensor, whatever).

 

[VernV]

Richpatty,
Most DEF tanks dont have a drain so you would have to drill and tap a drain plug opening or pump it out. When the DEF evaporates it leaves a salty looking residue that gums up the works. I dont have any other solution than to keep the tank filled up all of the time for this issue. If you age out the DEF then its pretty cheap insurance to drain it and refill with fresh. I dont think aging out is a big issue but have no direct experience. Our 4369 gets used very little and I had the same DEF level issue last year but since I have kept the tank full the level issue has not returned for me. We are going for a 4 day trip this weekend and hopefully we wont have any problems.

Neal,
The other issues (Shaw / Spartan, etc.) may be related to sensors that get coated or fail in some other way. The fluid itself is corrosive so that may be part of the problem. The system is mandated by the government but automotive work always goes to the lowest bidder so the cheapest parts always get used. It is also a huge problem with OTR trucks. The problem has gotten much worse in the last 5 years or so. Maybe by government mandate or just less and less of the older non DEF vehicles on the road. I dont have a good solution to the problem.
Vern

 

[Richpatty]

I did order a DEF tester…and I guess if it started to fail, I could try to siphon it out….

 

[Old-RV'er]

All - I posted a link to a YouTube video all about def. With that said, it's shelf life is about 6-8 months if it's at or above 85F, and 18 months if cooler than 60F. So I understand all concerns, but keeping the tank full to me is cheap insurance against the "gunk forming". I have also not used my MH as much in the last year, but about monthly or so take it up the road 10 miles, to keep stuff working, which does take DEF from the tank, and believe it puts back what it does not use, but it uses it just the same. So periodically I add new stuff, which should extend the shelf life to some degree. We have taken two trips this year so far, each less than 250 miles RT, and so using up the stuff, since lots of hills, going slow up and down, which uses the stuff lots. Once home will fill tank from jug which is new. To empty tank, I would just syphon it out into gallon jugs, and then find recycling center, and refill tank with new stuff. But if air cannot get to it, gunk will not form.

 

[jagpot]

It doesn't pass the common sense test to me. Someone needs to get with a vendor and find out the real story on how a DEF tank is designed and works. It seems to me the tank should be able to function down to completely empty and read tank levels as such. We are all trying to engineer something we no little of but all seem to speculate heavily about. Same with DEF sources when I have a feeling the Spartan/Shaw DEF issues are completely unrelated to the actual DEF in any way but is completely a computer issue (circuit board, sensor, whatever).

Our's it at Cummins as we speak. They said before looking at it,"I think this is a Newmar problem." The engine light code specifically said "after treatment". Is that not the DEF system? I'll keep you posted~!