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Typical DEF Usage

ITGuy

ITGuy

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What is typical DEF Usage for the Cummins 2500, my usage has been a tank every 3000 miles, which seems excessive.
 
ITGuy said:
What is typical DEF Usage for the Cummins 2500, my usage has been a tank every 3000 miles, which seems excessive.
Click to expand...

DEF usage depends on multiple factors. Are you towing, how much weight are you are towing, are you in tow/haul mode, do you idle a lot, etc.

For example, if you tow a 34,000 lb trailer, you can expect to use about a gallon of DEF per 198 miles. Skip to the 13:30 mark in this video.

If you aren't towing, you may be using excessive DEF because your truck needs a software update for TSB 18-052-19.
 
Thank you for the link and the TSB, I am not towing yet so I believe the TSB applies.
 
thestuarts said:
DEF usage depends on multiple factors. Are you towing, how much weight are you are towing, are you in tow/haul mode, do you idle a lot, etc.

For example, if you tow a 34,000 lb trailer, you can expect to use about a gallon of DEF per 198 miles. Skip to the 13:30 mark in this video.

If you aren't towing, you may be using excessive DEF because your truck needs a software update for TSB 18-052-19.
Click to expand...
Fuel mileage was a little disappointing as compared to other brands.
 
I had the W03 recall completed today and this includes the VB6 calibration. I asked about the DEF TSB and it is include as part of the update.
I had used approx 3 gallons of DEF with 2800 miles, no towing which seems high.
Will see how it is now after the update.

A note from the repairs states the following "The average consumption for DEF is 2% of the fuel economy. It will increase consumption if fuel economy decreases" I average 16mpg most of the time..
 
Hoping the same on DEF usage, how about anything else seems to be driving the same, so hoping mpg also increased :)
 
My MPGS are trending a few 10ths better by the trucks computer than before the recalls were completed. I haven’t drive enough yet to see if there is a reduction in DEF usage.
 
I am using 1 gallon per 438 miles. This is averaged over the last 3000miles. The dealer said they would flash the ecu. It was fine until it had its first service. I was towing a 9k trailer most of the time. Seems way over the top and it’s had the recalls.
 
When I pulled the toy hauler to OK and back for warranty work, I think mine was averaging about 550 mpg. Trailer was dry and empty, so about 12K lbs.

DEF use is higher than prior CTD, or the competition.
 
Nifty07 said:
I am using 1 gallon per 438 miles. This is averaged over the last 3000miles. The dealer said they would flash the ecu. It was fine until it had its first service. I was towing a 9k trailer most of the time. Seems way over the top and it’s had the recalls.
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That's about what I get when towing a trailer. 9k trailer I am going to get about 12mpg. My DEF usage is about 3% of fuel usage. 12 mpg would mean about 400 miles per gallon of DEF..
 
AKDoug said:
That's about what I get when towing a trailer. 9k trailer I am going to get about 12mpg. My DEF usage is about 3% of fuel usage. 12 mpg would mean about 400 miles per gallon of DEF..
Click to expand...
I have about 1700 miles on the truck - a combination of relatively light towing (about 9k) and empty. I've had to put 5 gallons of DEF in so far. Rough calculation is about 340miles per gal - not too happy about that. Had been reading that it should be around 700. Truck is a July 2020 build date. Dealer says no open TSBs on it, but I'm going to check further.
 
In the past when def was first introduced in diesel emissions the talk was, more def usage meant less egr. I don't know the whole truth to that but if so i'll pay the extra for def rather than more egr.
When I owned my 2008 6.7 Cummins "first year of dpf" prior to the introduction of def, I noticed my oil would get filthy much sooner than with the newer added def systems.
 
I have a 2019 2500 Longhorn and just got the TSB flashed and I dont see any real improvement. I used an 1/8 of a tank just doing some light freeway driving. I'm getting about 350-425 mpg on the def. My 2014 2500 got 5000-8000 on a tank. Going to monitor it more to see how it is.
 
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