Dep fluid useage in duramax

[JEROME]

I have a 2018 2500 duramax with a 6.6 .How will pulling a 3720 RL affect the amount of Dep fluid my truck will use? This is new to me . Thanks for any info you can give me . Jerome & Judy.

[team bradfield]

you will use more towing, my Ford has a DEF level gauge, very helpful. Every trip is different based on speed, head wind, inclines, etc. I carry 4 - 5 gallons with me while traveling

[DadsHemi]

Here’s an example, My Ram used 4 gallons from North Alabama to Southern California, I clocked 2300 miles, drove and average of 65 mph. My gross weight was 25,380.

[ohiocamp]

I have a 2018 Chevy Silverado 3500HD SRW and I use about a gallon every 500 miles towing a 3731FL.


ohiocamp

2018 3731FL

[kjmcdowell77]

I have a Silverado 2500 with a Duramax and pull a lighter weight Montana High Country. I find that when the engine is working harder with very little idling, it will use far less DEF. My truck will go into regen mode about every 200 miles around town but I have gotten almost 600 miles on the highway and 400 miles while towing the trailer.

[JEROME]

Thank you so much for all the info we are planning a trip west in the early spring from Fort Mill SC west who knows how far. Jerome& Judy

[mazboy]

here are some suggestions:
your truck will tell you when it is getting low so don't worry...you will have lots of miles--hundreds of miles.

secondly, when I fill up the def, any left over def i throwout. i was told to always us a fresh/new bottle of def. your system is very very sensitive to water and particles.
just in case, carry a fresh bottle of def with you.

[Last2Die]

How can you tell when the truck goes into regen..? I have a 2015 2500 duramax, Walmart has def for about 8$, 2.5 gallons. It doesn’t use much.

[MidMOTraveler]

You’ll most likely fuel up on occasion at truck stops. They will have DEF at the pump, most convenient and way more economical than jugs. I just keep mine topped off.

[twindman]

I have a Silverado. I can see a drop in milage when driving when it regens. Prior to 2011 (before DEF) the chevy had a setting to display instant or average MPG. After the change, the took out the instant. I am sure it was because people would be forever call chevy or the dealers about dropping from 17-19 mpg to 12-13 when driving without towing.
So when I suspect I am in regen, I reset the avg mph and for the next 30 seconds or so it is pretty much instantaneous mpg. Another way is sometimes when sitting idling, you can sort of feel the heat coming out the exhaust and sometimes it has a different smell. Plus I think I normally idle at 550 and during regen it is 650 - hard to tell unless you look closely.
Also, when I check instantaneous while towing, I am getting about 7-8 mpg vs. 11-12 mpg.

[Last2Die]

My 2015 Silverado has instant MPG. Don’t really keep it on the screen tho.

[CarWin]

Originally Posted by Last2Die

My 2015 Silverado has instant MPG. Don’t really keep it on the screen tho.

Our new Denali actually shows on Driver Info Center when it goes into "regen" mode.

[mhs4771]

This is getting confusing folks. Are we asking about DEF usage or how often it will go into Regen?? Two entirely different systems. Regens involve injecting Diesel Fuel into the Particle Filter to burn out the soot trapped there. Regens can be identified by an increased idle, when under load you will never know except for the drop in fuel mileage.
While DEF is injected into the SCR (Selective Catalytic Reduction) to reduce NOx emissions, and has no effect on mileage. DEF is injected in proportion to the amount of fuel burned, so towing heavy will use more DEF than running solo.

[twindman]

I wish they could reflash my truck so I could get the instanaeous mpg and tell me when a regen happens.

MHS, I guess you are right. I just associate regen and kkDEF as being the same since they both came in at the same time, I think.

[Mikendebbie]

I have not logged my DEF refills - I just put some in when the warning comes up on the DIC. I can’t tell when it is in regen while driving or towing...never have noticed...never have cared. From time to time I have smelled it in the exhaust while idling. I did have to have the 9th injector replaced under warranty at 75k or so. It has 98k on it now and it has been a better truck than my 03 2500 which I traded in for the 14 with 265k on it.

[rollingdownthehighway]

Just top it off before you roll out. I have a '16 3500 DRW I'll top it off if needed, but never had any issues. I'm pulling a 3700 LK and really never ran into heavy use or loss of the DEF fluid while towing to be honest. I've had my truck since 17' (bought it new) and only had to fill the DEF tank twice since I've had it.

[mazboy]

here is a good website for you.
https://www.dieselplace.com/forum/63...def-gauge.html


join the group.

[kjmcdowell77]

I usually watch my fuel economy on the center dash display. During regen, I drop about 4-5 miles per gallon on fuel for about 20-25 miles.

[mlh]

Originally Posted by twindman

I wish they could reflash my truck so I could get the instanaeous mpg and tell me when a regen happens.

MHS, I guess you are right. I just associate regen and kkDEF as being the same since they both came in at the same time, I think.

Regen and the DPF filter came on the 2008 model truck. DEF a few years later 2011, I think.
Lynwood

[twindman]

Lynwood, thanks for the info. I had a 2004 and went to a 2012 and the regen and DEF were new to me. I got luck and at about 60,000 I went in to the warning mode of going to limp mode in xxx miles. Got to a dealer and apparently I still had the 2011 NOX sensers and tank. Got it replaced under warranty. They had to run it like 2 hours or something to get the computer to reset to normal after all the new parts.