DEF tank still full

[DAN V]

So here is my situation. On Jan 29th I filled up the DEF tank with 2 jugs of DEF. I did this because I wanted to see how far I could go on a tank. When I did this I had around 3450 miles on the trip. Fast forward to now and I have 2100 miles on the gage and it has not moved yet. I called a local dealer and they said to drive it to 3000 and if it doesn't move then to come in and have it looked at. I know that the DEF tank is not like the fuel tank and does not have a float. I read somewhere that it has sensors inside. Is it safe to tap on the DEF tank to see if anything happens or should I leave it alone?

 

[Deleted member 995608]

I only have 2600 miles on my 2016. The DEF gauge needle just recently moved ever so slightly off the 100% mark. I think you're okay.

 

[AnOldBiker]

Don't have DEF, but from all I've talked to, it depends how it's used. Many have gone many miles without much DEF loss driving unloaded. But when working it hard, you can consume much more. And does anyone know how much you can put into it above te full mark ?

 

[HPSimpson]

When towing heavy load in the mountains of California with my 3500 dually and 28' Parker on triple axle trailer the def. gage really moves, just leave the tank alone the gage will move.

 

[Mingoglia]

Yeah, the gauge doesn't move fast, but drops like a rock once it starts moving, particularly when it gets to half. You don't want to keep it topped off if you're parking it in temps below I believe 18 degrees as that's when the DEF freezes. Yes, the DEF system is "designed" to be able to freeze, but it can't be completely topped off.

I've found the gauge is in fact approximately accurate when it's at 1/2, it's just not very linear at other parts of it's "travel". At 1/2, I will put a 2.5 gallon "box" of DEF in and it will be full according to the gauge. In realty it's not completely full, but it's full enough and still safe to freeze. When I run the truck all the way down until it yells at me for being low on DEF, I can fit 2 of these boxes of DEF and it will again bring it to the point of showing full, but still being safe to freeze. These are the two times I'll fill my DEF. I stick with this, and it works. Figure on a road trip I can always add DEF as all stations have it, and I only stop at truck stops so I know it's likely fresh.

In the summer time, things change. Unless I'm pulling a trailer I only keep my DEF between empty and half full. This is due to the decreased longevity of DEF in hot weather. This is particularly true when I'm in AZ, and less true when I'm in GA. I just run my system until it yells at me, like above, but at that point I only put one of the 2.5 gallon jugs and bring it to approximately half full. I only top it off in the summer if I'm pulling a trailer and putting on significant miles knowing I'll be burning it off.

 

[Kirwin]

My gauge doesn't move until around 3000 miles unless I'm towing a lot. Its not a float, its a sono probe. They are notorious for not being accurate when the tank is full. Once level drops to about 1/2, it will start moving fairly quickly off the full mark.

 

[DAN V]

Thanks for all the replies guys. I was just so used to it moving around 1800 miles. I have learned a lot from your inputs. Thanks.

 

[JDean]

Your DEF usage is approximately 2% of your fuel usage or about 50:1. So for every 50 gallons of fuel, plan on using 1 gallon of DEF. Your truck is fine. If it wasn't using DEF of wasn't using enough DEF the EVIC would be complaining about NOx levels and threatening to shut your tuck down.
- John D

 

[Newsa]

Your DEF usage is approximately 2% of your fuel usage or about 50:1. So for every 50 gallons of fuel, plan on using 1 gallon of DEF. Your truck is fine. If it wasn't using DEF of wasn't using enough DEF the EVIC would be complaining about NOx levels and threatening to shut your tuck down.
- John D

I have a 31 gallon fuel tank. But i don't put in a gallon of def every 2 fillups.

 

[photowrite]

Yeah, the gauge doesn't move fast, but drops like a rock once it starts moving, particularly when it gets to half.

This has also been my experience.

 

[JDean]

I have a 31 gallon fuel tank. But i don't put in a gallon of def every 2 fillups.

I don't track my def usage either, but in your example you probably could add a gallon of def every other fill if you wanted to assuming an average of 25 gallons per fill. It doesn't seem that way because you're more likely to add 2 1/2 gallons after 5 fills or even longer by the time you get around to it. The 50:1 ratio of fuel to def was from a Cummins article: https://www.cumminsfiltration.com/pdfs/product_lit/americas_brochures/MB10033.pdf.
- John D

 

[Bob4x4]

Just a heads up,there are 2 def tank sizes and only 1 pump assy.The larger tank will run much farther before the gauge begins to drop-so if you have the larger tank there's the reason.Something like a 2 gallon difference in tank sizes

 

[SnoKing]

What trucks have which? Empty mine goes forever. I think I have only added three 2.5 boxes in 8600 miles. One at home(1400 miles from delivery dealer) this fall, one in Crescent City, CA and one when we got to Arizona. Gauge is now on the move again. Chris

 

[Bob4x4]

Just one of those thing they brought at a training class looking at the books it appears they only claim a difference between c/c and pickups, at 5.5 and c/c at 9 gl-oh well,never trust an instructor that came from IH....

 

[gsbrockman]

Just one of those thing they brought at a training class looking at the books it appears they only claim a difference between c/c and pickups, at 5.5 and c/c at 9 gl-oh well,never trust an instructor that came from IH....

To add further confusion into the equation :-laf the Cab & Chassis DEF tanks have a serviceable DEF filter that requires periodic changing. The pickups do not..................

 

[Bob4x4]

There are screens in various locations inlets , outlets

 

[gsbrockman]

There are screens in various locations inlets , outlets

I don't doubt that one bit.....this is the DEF filter for the Cab & Chassis trucks:
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http://www.ebay.com/itm/Dodge-Ram-C...Exhaust-Fluid-Fuel-Filter-Mopar-/331037999785

 

[photowrite]

If DEF needs filtering then I like the idea of a filter. Of course commercial trucks also have coolant filters and pickups do okay without those too.

 

[Brocky]

GS
Where is this filter located on the C&C?? And how often do you change it??

Thanks in advance
Brocky