DEF Tank gauge range

[DAN V]

I currently have just under 3900 miles on truck since I purchased about a month ago. DEF tank was full when got truck. Right now it is about 2 needles above 1/4 tank. Just curious how far I can take it before the light comes on? I do have a jug a DEF in truck when I am ready to put into tank. Another guy I work with is doing the same as me and trying to see how far he can go also. Is it safe to go beyond 1/4 tank or should I go ahead and fill up? This is my first DEF truck so this is why I am asking. Thanks.

 

[Newsa]

You will get different opinions on this. Here's my 2 cents.
DEF has a shelf life of 2 years @ 70 degrees F.. So if there is any Def in the tank from 2013 ( that is 2 years old), it could make your DEF sensor detect bad def.
If you live in Arizona or South California where the ambient temps can daily exceed 100 degrees, DEF can expire even quicker in the tank, especially when over hot pavement. Shelf life includes how long its in the warehouse, store, bulk tank, and truck def tank.

Mine is currently a needle-width below 1/4. But since the tank gauge is not linear, I think it really only has about 1/2 gallon left in the tank.

I like to let mine run out until the EVIC gives me a 200 mile warning so I know there isn't expired residual def in the tank.

Many like to buy it out of the pumps (bulk def) @ truck stops. However, last summer when i was at a Loves, I was surprised at how few semi's actually use DEF. There was a military convoy fueling up and I had a chance to jaw with some truckers. None of whom required DEF for their trucks.

So, not sure that bulk DEF is any better than jug def. But you know the DEF in the bulk tanks is underground and not getting hot.

 

[Brocky]

Newsa:
Are you sure all of the bulk DEF tanks are underground??? Our trucking company terminal has the 500 gal(??) plastics lined wire mesh tote bins in the garage and plumbed out to the fuel pump..

Dan:
My 2014 C&C has the 9 gal tank so I let it get below 1/2 and add 5 gal, which never fills it up all the way.But the gauge stays on full for a long time then starts to drop fast!! Right now it is getting down to to almost 1/4 and will get 3 jugs this week at NAPA to see if I can fill it full?? Then will be towing about 2000 miles in the next month. As long as I purchase DEF at an active supplier (My NAPA dealer goes thru his 12 case supply every week or two) I feel that I burn it fast enough to not have to worry about shelf life.

Mr Wilson:
How do you store / sell / dispense DEF at your dealership?? And how do your customers do the same?? This might give the recreational user some better idea how to purchase and store their DEF. Thanks Brocky

 

[gsbrockman]

I currently have just under 3900 miles on truck since I purchased about a month ago. DEF tank was full when got truck. Right now it is about 2 needles above 1/4 tank. Just curious how far I can take it before the light comes on? I do have a jug a DEF in truck when I am ready to put into tank. Another guy I work with is doing the same as me and trying to see how far he can go also. Is it safe to go beyond 1/4 tank or should I go ahead and fill up? This is my first DEF truck so this is why I am asking. Thanks.

There's no definitive answer as it depends on terrain, whether you're towing, etc. etc. etc.....
Initial message :
#ad


Generally after receiving the above notification, I can run anywhere from 60 to 110 miles before it enters countdown mode :
#ad


I've ran it down below the de-rate message....if there's any interest, I'll try to see if I can locate the picture.

 

[DAN V]

There's no definitive answer as it depends on terrain, whether you're towing, etc. etc. etc.....
Initial message :
#ad


Generally after receiving the above notification, I can run anywhere from 60 to 110 miles before it enters countdown mode :
#ad


I've ran it down below the de-rate message....if there's any interest, I'll try to see if I can locate the picture.

Where was your DEF gauge at if you can remember? Below 1/4 tank?

 

[gsbrockman]

Where was your DEF gauge at if you can remember? Below 1/4 tank?

< 1/8th of a tank or so.

 

[Stab]

I don't even worry about it anymore! With all the hassle of refilling, I just wait for the 199 mile count down before I even think about a refill. BUT I always have a 2 gallon jug on hand! It does exactly what it says in the manual.

 

[BatMan01]

My experience is about the same as everyone's. I drove it off the dealer lot with a full tank and put my first almost 600 miles on it without towing and the gauge stayed on full. I then took my 5th wheel down the road (354 miles) and the gauge moved to just below 3/4. I'm not at 2000 and im just above a half a tank showing on the gauge.

......

 

[EDankievitch]

Driving Bobtail your DEF use is about 1 gal per every 1000-1500 miles. When towing the use goes up to 1 gal per 450-550 miles. I made it almost 3/4 of the way on a round trip from Ny to Fla Keys on a full tank of DEF before the low DEF warning came on. the DEF tank holds something around 6 gal. When the low DEF warning first comes on two 2.5 gal DEF jugs will not fit ask me how I know.....

 

[MattandLana]

Just a note on shelf life - seems it's not just ambient temperature but also exposure to sunlight.

Cummins says: "The shelf life of DEF is a function of ambient storage temperature. DEF will degrade over time depending on temperature and exposure to sun light. Expectations for shelf life as defined by ISO Spec 22241-3 are the minimum expectations for shelf life when stored at constant temperatures. If stored between 10 and 90 deg F, shelf life will easily be one year. If the maximum temperature does not exceed approximately 75 deg F for an extended period of time, the shelf life will be two years."

You can find this, and anything else you ever wanted to know about DEF, and a whole bunch more than that, too, in this Cummins brochure.

 

[Newsa]

Hence, take it out of the bed of your truck. Even if it's covered. Better to just put it in your tank. This is why hydrogen peroxide is sold in brown bottles.