I find it better to ask how many gallons of fuel per jug, in my case it’s about 47 gallons of fuel per jug of DEF, miles per jug depends on fuel mileage

 

DEF usage is between 2 and 3% of your fuel usage typically. So you'll go through 2-3 gal of DEF per 100 US gal of fuel (375 is L).

 

No disrespect but is that documented anywhere? I’m using between 4.5 to 5 percent and if I find documentation I’ll go back to the dealer

 

3% of fuel for me. 18.2 gal of DEF compared to 602 gal of fuel over 17159 miles.

 

Determine Your DEF Consumption | Proformance Supply

DEF consumption is directly related to fuel consumption. If you know your vehicle's average fuel consumption, you can easily calculate the amount of DEF that will be used.

proformancesupply.com

 

Unless towing, the baby Duramax should be sipping DEF. I’ve never actuallly kept track of it because it doesn’t use much at all but I go thru about 3 jugs (maybe 4 max) in approx 13,000 miles (a year).

 

I think I use about a jug per 12k. Basically one jug per oil change interval

 

I think I went through about 5 jugs in 30,000 miles.. no towing..

 

About 2000-2500 miles not towing for 2.5 jug

 

10 jugs in 6500 miles, all towing. Lol

 

It does seem like the LZ0 uses more DEF than the LM2.

 

The LZ0 has stricter emissions on it than the LM2.
It has two def injectors vs 1 in the LM2 and also as far as I know it has the SCFR like the lm2 but also a traditional dpf as well which the lm2 doesn’t have.
the LZ0 regens a lot more frequently as well likely due to the tighter tolerances.
I remember reading somewhere it was the reason for changing the LM2 to the LZ0 was the LM2 wasn’t going to meet the new standards or something.

 

According to the manual, you can add 2.5 gallons of DEF when 3 bars show on the display....

( Does anyone EVER read these things????)

 

that is probably accurate. I add a jug when my def level hits about 50% on the idash (which takes it up to 90% I think). I think 50% on the idash is about 3 bars on the DIC.

 

I got 900 miles to go till empty notice on the dash and I dumped two 2.5-gallon containers in. Full after that. Should be good for at least a year.....