DEF Consumption
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Joined: Apr 2013
Posts: 10,118
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From: NH
DEF Consumption
Wondering if any of you have the same observation as me: this 2017 truck uses considerably more DEF than the old generation.
I have 1800 miles on my truck and the DEF gauge is showing 50% remaining. The old truck would easily go 5k miles between DEF refills. Looks like I'll maybe get 4k miles, plus this tank is 2.5 gallons larger.
I have 1800 miles on my truck and the DEF gauge is showing 50% remaining. The old truck would easily go 5k miles between DEF refills. Looks like I'll maybe get 4k miles, plus this tank is 2.5 gallons larger.
Senior User
Joined: Nov 2010
Posts: 481
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Found this on a def FAQ sheet...
DEF consumption is directly related to fuel consumption. A truck averaging 6 MPG can expect to go approximately 300 miles on one gallon of DEF.
Q. How can an operator determine how much DEF they will need/use?
A. DEF consumption will be approximately 2% of the diesel fuel consumed. Another way to consider it is that DEF will be consumed on a 50 to 1 ratio with diesel. (For every 50 gallons of diesel fuel burned, you will use 1 gallon of DEF). If you know the average fuel consumption of a vehicle, you can easily calculate the amount of DEF that will be used.
Annual miles for average truck = 50,000 miles
MPG for average truck = 8 mpg
50,000 miles / 8 mpg = 6,250 gallons diesel fuel per year
DEF usage @ 2% of fuel consumption = 125 gallons of DEF / year 125 gallons / 10 gallon tank (average size) = 13 DEF fill-ups / year
By this math i have used 2.83 gallons of def. Seems legit
DEF consumption is directly related to fuel consumption. A truck averaging 6 MPG can expect to go approximately 300 miles on one gallon of DEF.
Q. How can an operator determine how much DEF they will need/use?
A. DEF consumption will be approximately 2% of the diesel fuel consumed. Another way to consider it is that DEF will be consumed on a 50 to 1 ratio with diesel. (For every 50 gallons of diesel fuel burned, you will use 1 gallon of DEF). If you know the average fuel consumption of a vehicle, you can easily calculate the amount of DEF that will be used.
Annual miles for average truck = 50,000 miles
MPG for average truck = 8 mpg
50,000 miles / 8 mpg = 6,250 gallons diesel fuel per year
DEF usage @ 2% of fuel consumption = 125 gallons of DEF / year 125 gallons / 10 gallon tank (average size) = 13 DEF fill-ups / year
By this math i have used 2.83 gallons of def. Seems legit
Prolocutor
Joined: Jan 2009
Posts: 13,618
Likes: 1,245
From: Western MA
My thoughts exactly. You will def burn a lot more while towing. Tyler, are you sure it was full on delivery?
Post Fiend
Joined: Jun 2006
Posts: 5,497
Likes: 7
From: Central, Al
Just hit 1500 miles and DEF is right at 7/8 of a tank, haven't towed anything heavy yet but about 50/50 mix of city and highway driving. She will get a good breakin before heavy towing when I play musical tractors after hunting season.
On a side note doesn't the '17 have a 7.2 gal DEF tank?
On a side note doesn't the '17 have a 7.2 gal DEF tank?
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Hotshot
Joined: Apr 2013
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From: NH
Fidel's comments make a little bit of sense - this truck definitely gets worse economy than my 2016 SRW - so maybe it is to be expected.
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Tuned
Joined: Oct 2005
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Every new Ford I've ever had, gas or diesel, takes a few miles to break in. After that, MPG goes up quite a bit.
I see you've owned a passel as well. Do you recall if that was the case in your other trucks?
Posting Guru
Joined: Oct 2005
Posts: 1,460
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Yeah...same here. My 2001 got 15/16 right out of the box...and the DEF lasted forever. My new '17 is moving between 13/14.5 for the first 500 miles or so. I've been doing some short trips...with one 200 miler in there. I was hoping to see that mpg bump up to 16 or 17 but it's just not happening yet. We'll see. My 2011 didn't need any "breaking in" to see decent mileage...or at least the mileage that it would average for the life of the truck. Can't really comment on DEF usage yet....but yeah....mpg is just not where I thought it would be.
Cargo Master
Joined: May 2002
Posts: 2,530
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From: Montana
Yeah...same here. My 2001 got 15/16 right out of the box...and the DEF lasted forever. My new '17 is moving between 13/14.5 for the first 500 miles or so. I've been doing some short trips...with one 200 miler in there. I was hoping to see that mpg bump up to 16 or 17 but it's just not happening yet. We'll see. My 2011 didn't need any "breaking in" to see decent mileage...or at least the mileage that it would average for the life of the truck. Can't really comment on DEF usage yet....but yeah....mpg is just not where I thought it would be.
Senior User
Joined: Oct 2016
Posts: 163
Likes: 1
We should also share rear axle ratio. My 2017 was running about 14 to 15 mpg with a 3.55 axle when I first got it. I now have 900 miles on it and its gotten better, I've not hand calculated it but the computer says 16.5 for my last trip. My 2012 started out like this too, it finally maxed out around 17 for average mileage.