def tank

roy2

Well-known member
hello everybody just looking to get some information i have 2019 3500 ltz dully truck my def tank is 8 gal i think pretty sure of that. any way when my tank is low when the massage come up on my screen it tells me i have 600 miles left driving it.does any one know how much i can fill it up again before it runs over. thanks.
 

LBR

Well-known member
hello everybody just looking to get some information i have 2019 3500 ltz dully truck my def tank is 8 gal i think pretty sure of that. any way when my tank is low when the massage come up on my screen it tells me i have 600 miles left driving it.does any one know how much i can fill it up again before it runs over. thanks.
I've tracked my Def mileage on our 2017 F-450 since new. I try never to let it fall below 1/2 to avoid the sensor seizure problems previous year F series could develop, so I usually only put 4-5 gallons total in per fill-up.

The mileage is a huge swing between towing vs. empty, but mine has been consistently showing:

A scootch over 500 MPG when mostly towing

A scootch over 1000 MPG when mostly empty.
 

roy2

Well-known member
I can normally get 5 gallons in when that warning comes on.
do you have a 8 gallon tank also.

- - - Updated - - -

I've tracked my Def mileage on our 2017 F-450 since new. I try never to let it fall below 1/2 to avoid the sensor seizure problems previous year F series could develop, so I usually only put 4-5 gallons total in per fill-up.

The mileage is a huge swing between towing vs. empty, but mine has been consistently showing:

A scootch over 500 MPG when mostly towing

A scootch over 1000 MPG when mostly empty.
thanks for your info but i dont have a gage on mine it just shows up when its low its shows 100 % then pops up 10 % and it tells me i have 600 miles left before it runs out on me. thanks again.
 

NYSUPstater

Well-known member
FWIW, I ave about 5k between fill ups and put in 6-6.5 gal out of a 7 gal tank. So that's pretty much just 2x/yr.
 

ILH

Well-known member
I don't have any empirical evidence to back up my statement - but it seems that my 2018 RAM (3500 dually) consumes more DEF than my 2011 2500 GMC. Same trailer for both trucks, so the pulling weight is the same. My 2011 GMC didn't have a gauge for the DEF tank (dumb!) - so it was guess-as-you-go, whereas the RAM has a nice gauge on the dash.
 

danemayer

Well-known member
I don't have any empirical evidence to back up my statement - but it seems that my 2018 RAM (3500 dually) consumes more DEF than my 2011 2500 GMC. Same trailer for both trucks, so the pulling weight is the same. My 2011 GMC didn't have a gauge for the DEF tank (dumb!) - so it was guess-as-you-go, whereas the RAM has a nice gauge on the dash.

My 2014 RAM definitely uses twice as much DEF while towing as the 2011 GMC did. The GMC got around 1,000 miles per gallon. The RAM gets around 500.

On a different DEF topic, I had a DEF error light on Friday morning. Ambient temp was around 18 (F). But the front of the truck was sitting in the sun and when I started it, the dashboard ambient temperature was reading something like 47 (F) - from the sun warming the hood and windshield.

I've had a similar problem on the GMC. There's a temperature sensor on the DEF reductant tank so it knows when temps are below freezing, beccause the DEF is probably frozen solid. So there's no DEF usage in that condition. But if the ambient temperature sensor reads well above freezing and the DEF sensor below freezing, the computer considers that an error and lights up the dashboard.

On the GMC, it would produce a check engine light that stayed on until reset. On the RAM, the error cleared at the next stop because the temperature sensors were in agreement.
 
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