Diesel Exhaust Fluid Range

I don't have a diesel but why not top it off at every oil change? If you do with your tested 15,000 mile range you should never have to worry about running low.

I got 11,000 miles out of mine before I got the first add exhaust fluid indications.

Since DEF has a shelf life and temp makes a difference on it. I plan on running mine down to when I need it and then top off from there. Pluse there is a truck stop not to far from me that has it at the pump.

It seems the higher the temperature the lower the shelf life, so if you live in a hot climate like Phoenix AZ I would think it would have a shorter SL than someone living in Washington State.

https://www.fcsdchemicalsandlubricants.com/main/additionalinfo/DEF Shelf Life and Fluid Quality.pdf

Talking to one of the techs at the dealership when I had the oil changed last on our diesel (the first one we had to pay for - still cheaper than me doing it) - they've actually found that adding it when it doesn't really need it (i.e. every oil change) seems to cause issues. They only like to add it when it's actually lower.

MP81 said:

Talking to one of the techs at the dealership when I had the oil changed last on our diesel (the first one we had to pay for - still cheaper than me doing it) - they've actually found that adding it when it doesn't really need it (i.e. every oil change) seems to cause issues. They only like to add it when it's actually lower.

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theyve had too many marijuanas

def quality, lack of more specifically is overstated

we constantly had trucks sit for a year, def in them and when we would run them, the def is fine

none of our mechanics ever found a def quality issue, nor did any of the field mechanics that would roll thru...its one of the first things you check for cuz its easy to check, but just never happens.

MP81 said:

Talking to one of the techs at the dealership when I had the oil changed last on our diesel (the first one we had to pay for - still cheaper than me doing it) - they've actually found that adding it when it doesn't really need it (i.e. every oil change) seems to cause issues. They only like to add it when it's actually lower.

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I add when it gets to 35%, sometimes sooner. never had an issue in 146K miles.

diesel said:

I add when it gets to 35%, sometimes sooner. never had an issue in 146K miles.

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Being new to the DEF thing, how long (generally??) is it lasting per tankful of DEF?? I am hearing some guys say 8,000 miles, @LiveTrash above got 15K out of a tank. Also, how long between oil changes are you guys getting before the DIC is saying take her in for an oil change?? My Toyota goes 10 K between oil changes on synthetic and so do the AMGs.

GlennGlenn said:

Being new to the DEF thing, how long (generally??) is it lasting per tankful of DEF?? I am hearing some guys say 8,000 miles, @LiveTrash above got 15K out of a tank. Also, how long between oil changes are you guys getting before the DIC is saying take her in for an oil change?? My Toyota goes 10 K between oil changes on synthetic and so do the AMGs.

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depends on your mpg and your emissions working properly...the better your mpg, less def youll use...if the system thinks theres too much nox, cuz of bad sensor or such, itll add more def

if theres bulk def near you thats convenient, pump it when you want to...way cheaper

35% or lower will take the entire 2.5g bottle available everywhere....if you dont wait til then you run the risk of spills, its a pita to clean, all crusty and such

i aint got def pumps anywhere near me, so i do jugs.......sometimes in winter, the def level indicator will stick...and ill miss the 35% warning, itll go straight to 30 or lower, conversely after you fill it, it could take a couple days for it to register full again...ymmw

im changing oil when DIC is ~5% which is avg 10,000 miles....def usually isnt showing needed

im away at work for 20 days then home for 10 days...to avoid having to lug def around with me ill top it off when convenient for me, usually day before i leave for work

and that the tank is in the trunk under the floor, you gotta move stuff outta the way, prop something up to hold the floor up to fill the tank, who would wanna do that more often than needed?

LiveTrash said:

Just got a message on a brief run I did this morning in the car. About halfway through the run I got the DIC message pop up saying "Diesel Exhaust Fluid Range: 1518 km". I flipped the screens over to the percentage remaining indicator and it read 9%. If it's accurate, it seems my factory filled tank of DEF will last me about 24,500 kilometers (15,223.59 miles). I do about half city and half highway driving. The dealership gave me a small bottle of the stuff to fill up when I need which doesn't seem to be enough to fill even half the tank. I'll go how ever long I can on that and then buy a larger jug of it from my local truck store.

Has anyone else run close to empty on their DEF or do you usually keep it topped up every oil change?

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that sounds about right, I`ve only topped up mine 3 times in 55,000 kms

I go a year on a tank of DEF. 17,000 miles.

GlennGlenn said:

Being new to the DEF thing, how long (generally??) is it lasting per tankful of DEF?? I am hearing some guys say 8,000 miles, @LiveTrash above got 15K out of a tank. Also, how long between oil changes are you guys getting before the DIC is saying take her in for an oil change?? My Toyota goes 10 K between oil changes on synthetic and so do the AMGs.

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I never really measured my DEF consumption, but it doesn't seem all that often. My DIC seems to be hard coded to 7500 miles. I have been resetting it once and going through 2 (15K miles) per oil change. but for me, that's like every 3 months. There's an oil analysis thread on here where I posted my results. 15K seems to be a happy medium for oil life, given my driving habits.

The GM Oil Life Monitior system is in fact hard set to 7,500 miles. But it will also accelerate the countdown depending on other factors such as engine revolutions or time. I plan on changing my oil between 5-6,000 miles. My monitor is at 26 percent, sitting at like 5,600 miles.

LiveTrash said:

Just got a message on a brief run I did this morning in the car. About halfway through the run I got the DIC message pop up saying "Diesel Exhaust Fluid Range: 1518 km". I flipped the screens over to the percentage remaining indicator and it read 9%. If it's accurate, it seems my factory filled tank of DEF will last me about 24,500 kilometers (15,223.59 miles). I do about half city and half highway driving. The dealership gave me a small bottle of the stuff to fill up when I need which doesn't seem to be enough to fill even half the tank. I'll go how ever long I can on that and then buy a larger jug of it from my local truck store.

Has anyone else run close to empty on their DEF or do you usually keep it topped up every oil change?

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If I remember correctly I went about 13k miles on the factory DEF fill before it was low enough for my comfort. Now whenever it says a percentage left I'll dump a 2.5gal container of DEF in.

Adding to the DEF conversation, I just filled mine since I am getting the oil changed tomorrow. The car has like 5,600 miles on it. I made sure it was filled when I got it, it had like 150 miles on it, it took like 1/4 gallon. Today it took 1 and 1/4 gallons.