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Ram 2500 DEF fluid

samhain7
Explorer
Explorer
Hi all
I am on tank of gas # 6 on my new to me truck and thrnDEF fluid gage has barely even moved

How long do you get on a tank of DEF fluid and how big is the reservoir?

Thanks
Final notice from MasterCard. Good! I'm sick of hearing from them.
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2016 Dodge Ram 2500 Cummins, E2 WD w/sway
2015 Starcraft Autumn Ridge 289BHS
45 REPLIES 45

wanderingbob
Explorer II
Explorer II
On my 2500 CTD , when gauge sez 1/2 I pour in 2 1/2 gallons . But you are correct , it will say full and then " bang " , it is on half !

trail-explorer
Explorer
Explorer
samhain7 wrote:
Hi all
I am on tank of gas # 6 on my new to me truck and thrnDEF fluid gage has barely even moved


Why does a gas powered truck have a DEF gauge?
Bob

mudfuel07
Explorer
Explorer
When I had to use it on mine, I think I was putting in a jug every couple of months, maybe every 5-6 tanks. It really burns through it when towing, I felt like I could see the gauge move.
2020 Ram 2500 6.7 CTD 4x4 Tradesman(with a few toys)
2020 Puma by Palomino 32RBFQ for the kids!

markandkim
Explorer II
Explorer II
Bionic Man wrote:
In theory, you should need DEF about the same time you need an oil change. But there are a LOT of variables to that.

Your DEF gauge is probably working just fine. You shouldn't need to fill after 6 tanks of fuel. According to Cummins, DEF consumption is 3% - 5% of your total fuel consumption.

The DEF tank on a 2016 2500 is 5.5 gallons.


It won't last 15000 miles. That is when the oil change is due.
1/2 of a tank of DEF goes about 3000 miles.
Retired Navy

2020 Ram 2500 Bighorn 6.7L
2014 Crossroads Zinger 27RL
2022 Grand Design Reflection 315RLTS

ACZL
Explorer
Explorer
As already stated, it varies a lot (towing VS not towing), but in general, you will only fill the DEF 1-2x/yr.
2017 F350 DRW XLT, CC, 4x4, 6.7
2018 Big Country 3560 SS
"The best part of RVing and Snowmobiling is spending time with family and friends"
"Catin' in the Winter"

ShinerBock
Explorer
Explorer
The DEF usage ratio is about 50 to 1 per Cummins meaning for every 50 gallons of diesel fuel burned, you will use 1 gallon of DEF. The less miles per gallon you get in fuel, the less miles per gallon you get in DEF. So if you are getting 15 mpg, then you are getting 750 mpg in DEF. If you are getting 10 mpg, then you are getting 500 mpg in DEF. Basically, multiply 50 times your MPG and you will get your DEF mpg.
2014 Ram 2500 6.7L CTD
2016 BMW 2.0L diesel (work and back car)
2023 Jeep Wrangler Rubicon 3.0L Ecodiesel

Highland Ridge Silverstar 378RBS

RamRider
Explorer
Explorer
I usually top up my DEF at around 6000 miles or when it shows 1/2 full. Use of DEF is proportional to fuel use, thus when towing you will use more fuel and more DEF but even so you are not using much DEF
happy travels
2014 Airstream 25FB
2016 Ram
Blue Ox Sway Pro
ARE Topper

Lynnmor
Explorer
Explorer
samhain7 wrote:
Lynnmor wrote:
Your gas truck will run forever without filling the DEF tank. :W

The answer to your question is in the owners manual.


Gee, thanks for the help
:R


You're welcome.
I just thought that I didn't want to sit and type up everything that you already have in your possession. :R

kirkl
Explorer
Explorer
My Ram will go about 4000 miles and use half a tank of DEF if not towing so yes the guage will move slowly. Towing it will use more.
2017 Ram 2500 6.7 Cummins 4x4 LB
2018 Wildcat Maxx 28RKX
2014 Adventurer 80RB

samhain7
Explorer
Explorer
Bionic Man wrote:
In theory, you should need DEF about the same time you need an oil change. But there are a LOT of variables to that.

Your DEF gauge is probably working just fine. You shouldn't need to fill after 6 tanks of fuel. According to Cummins, DEF consumption is 3% - 5% of your total fuel consumption.

The DEF tank on a 2016 2500 is 5.5 gallons.


Thanks Bionic man. Great information.
Yes, everything is on the net, but sometimes it is nicer to interact with people and listen to stories rather than just read a book.
Thanks for taking the time to respond.
Final notice from MasterCard. Good! I'm sick of hearing from them.
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2016 Dodge Ram 2500 Cummins, E2 WD w/sway
2015 Starcraft Autumn Ridge 289BHS

samhain7
Explorer
Explorer
Lynnmor wrote:
Your gas truck will run forever without filling the DEF tank. :W

The answer to your question is in the owners manual.


Gee, thanks for the help
:R
Final notice from MasterCard. Good! I'm sick of hearing from them.
-----------------------------------------------------------------
2016 Dodge Ram 2500 Cummins, E2 WD w/sway
2015 Starcraft Autumn Ridge 289BHS

Bionic_Man
Explorer
Explorer
In theory, you should need DEF about the same time you need an oil change. But there are a LOT of variables to that.

Your DEF gauge is probably working just fine. You shouldn't need to fill after 6 tanks of fuel. According to Cummins, DEF consumption is 3% - 5% of your total fuel consumption.

The DEF tank on a 2016 2500 is 5.5 gallons.
2012 RAM 3500 Laramie Longhorn DRW CC 4x4 Max Tow, Cummins HO, 60 gallon RDS aux fuel tank, Reese 18k Elite hitch
2003 Dodge Ram 3500 QC SB 4x4 Cummins HO NV5600 with Smarty JR, Jacobs EB (sold)
2002 Gulf Stream Sea Hawk 29FRB with Honda EV6010

spoon059
Explorer II
Explorer II
The DEF gauge isn't linear. It will show full until its about half a tank, then it will quickly drop down towards empty. One day you will get a warning that DEF is low, that is usually when I fill up. If you don't fill up then, you'll eventually start getting messages saying 250 miles to shutdown, etc.

During the summer we take shorter trips, so I just dump 2.5 gallon jugs in when I get the low DEF warning. In the winter we take a long trip, so I usually fill the DEF at a pump, so I can fill the tank.
2015 Ram CTD
2015 Jayco 29QBS

Cummins12V98
Explorer III
Explorer III
samhain7 wrote:
Hi all
I am on tank of gas # 6 on my new to me truck and thrnDEF fluid gage has barely even moved

How long do you get on a tank of DEF fluid and how big is the reservoir?

Thanks


Your problem is you have been putting "GAS" in your Diesel Truck.
2015 RAM LongHorn 3500 Dually CrewCab 4X4 CUMMINS/AISIN RearAir 385HP/865TQ 4:10's
37,800# GCVWR "Towing Beast"

"HeavyWeight" B&W RVK3600

2016 MobileSuites 39TKSB3 highly "Elited" In the stable

2007.5 Mobile Suites 36 SB3 29,000# Combined SOLD

Lynnmor
Explorer
Explorer
Your gas truck will run forever without filling the DEF tank. :W

The answer to your question is in the owners manual.