# 2015 F250 Superduty 6.7 Diesel fuel related questions



## Dogplow Dodge (Jan 23, 2012)

Ok, so I'm caretaking this superduty for my friend.

How many gallons of fuel do you put in the tank when it says it's empty on the computer screen ? Yesterday, I filled this truck up, and it took 23.5 gallons, and it said it was a couple miles till empty. I can assume that there is a reserve amount left in the tank, as manufacturers don't want you to run dry a diesel. IF not, what gives ?

A 24 gallon tank ? I guess I could pull the owners manual, but I figured I ask what you guys have. Buff says his is "30-ish" did this 2015 come with a smaller tank ? 

This thing gets terrible mileage. Yes, it's pulling a trailer, and only 7,000 miles on the clock, but wow.....


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## DieselSlug (Nov 30, 2009)

My 09 manual says its 30 gallons, and you look all over the internet and see 30.

I've honestly struggled to put 23 gallons in mine. Maybe they aren't filling all the way? 

I have never had a tank this small and it sucks! Id love to get a titan, but they don't make them for the gas trucks, only diesels.

My 5.4L gets 11 mpg on a big lift and 37's. Its gutless.


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## doh (Sep 23, 2003)

I would NEVER run a diesel that close to empty. Unless you have the extra cash for 8 injectors.


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## Dogplow Dodge (Jan 23, 2012)

doh;2057557 said:


> I would NEVER run a diesel that close to empty. Unless you have the extra cash for 8 injectors.


My 92 dodge brick has a 30 gallon tank. It claims it's empty with 6 gallons still in there. I can assume that these trucks are the same for the reasons you just mentioned.

If I ever purchase a new truck, I'm ordering it with dual tanks (if available), otherwise, I'm sure there is an aftermarket supplier of larger tanks.

Crazy for such a large vehicle to have a limited range (small tank), IMO.


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## SnoFarmer (Oct 15, 2004)

Dogplow Dodge;2057579 said:


> My 92 dodge brick has a 30 gallon tank. It claims it's empty with 6 gallons still in there. I can assume that these trucks are the same for the reasons you just mentioned.
> 
> If I ever purchase a new truck, I'm ordering it with dual tanks (if available), otherwise, I'm sure there is an aftermarket supplier of larger tanks.
> 
> Crazy for such a large vehicle to have a limited range (small tank), IMO.


I dont know if it is crazy small, I can go across N.Dakota and only have to stop once for fuel. 32gal tank.....

on that new Ram your eyeing I believe they have a option for to up it to 50gal but it puts the spare tire in the box.

I have to stop to pee before I can run the tank dry...

if fuel and range is a issue get a slip tank in the box....


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## 1olddogtwo (Aug 6, 2007)

Dogplow Dodge;2057490 said:


> Ok, so I'm caretaking this superduty for my friend.
> 
> How many gallons of fuel do you put in the tank when it says it's empty on the computer screen ? Yesterday, I filled this truck up, and it took 23.5 gallons, and it said it was a couple miles till empty. I can assume that there is a reserve amount left in the tank, as manufacturers don't want you to run dry a diesel. IF not, what gives ?
> 
> ...


That's about right, its a 26 gallon tank thanks to the DEF tank being needed.


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## SnoFarmer (Oct 15, 2004)

The short bed has a 26 gallon tank and the long bed a 36 gallon tank.


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## 1olddogtwo (Aug 6, 2007)

Yea, and for the life of me I can't figure out why Ford does that

My CCSB has a longer wheel base then a SCLB.

Titan tank offers a 50 gallon replacement for the short beds.


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## tjctransport (Nov 22, 2008)

because the 36 gallon tank will not fit under a short bed truck. 

9-10 MPG is bad, that is what our F550 crew cab 4X4's are getting loaded at 23,000+ lbs. the F350 with 65k miles and delete kit is getting close to 18 mpg and that usually runs around 12,000 lbs.


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## Dogplow Dodge (Jan 23, 2012)

tjctransport;2057846 said:


> because the 36 gallon tank will not fit under a short bed truck.
> 
> 9-10 MPG is bad, that is what our F550 crew cab 4X4's are getting loaded at 23,000+ lbs. the F350 with 65k miles and delete kit is getting close to 18 mpg and that usually runs around 12,000 lbs.


Will it improve once the motor is broken in ? With only 7k on the engine, it's not even scratched the surface, I would imagine.

His tires were a little low, so I filled them. We'll see if the trip I have to make with it, the mileage improves.

BTW, Check your PM.


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## 1olddogtwo (Aug 6, 2007)

tjctransport;2057846 said:


> because the 36 gallon tank will not fit under a short bed truck.


Yes it does, I put one one my 2012.

Unloaded, that is low, way low.


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## lfaulstick (Sep 7, 2009)

wish my f550 got 9-10mpg i am getting 7.5-8.2 according to computer


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## Derek'sDumpstersInc (Jul 13, 2014)

My F-550 Chassis cab gets 9.4 mpg all day long hauling my mowers around or running my dumpsters. But it is a hooklift, so some of that is do to running the engine at 2k rpm while sitting still to cycle the hoist on and off 10 times a day.

5.88 gears also don't help.


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## Banksy (Aug 31, 2005)

doh;2057557 said:


> I would NEVER run a diesel that close to empty. Unless you have the extra cash for 8 injectors.


I dropped a tank on a 1998.5 Cummins Dodge once (in 2009) to install a FASS system. The bottom of the tank was clean. The truck was stock and it was clear I was the first one to drop the tank.

IMO, this don't run the tank too low thing is more myth than truth.


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## abbe (Sep 8, 2009)

Banksy;2057944 said:


> I dropped a tank on a 1998.5 Cummins Dodge once (in 2009) to install a FASS system. The bottom of the tank was clean. The truck was stock and it was clear I was the first one to drop the tank.
> 
> IMO, this don't run the tank too low thing is more myth than truth.


I don't think he is inferring that the damage will come from junk on the bottom of the tank, but rather from running the injectors without fuel in them and cause damage from lack of lubrication and then the whole priming process which must be a nightmare on these trucks.


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## Banksy (Aug 31, 2005)

abbe;2058123 said:


> I don't think he is inferring that the damage will come from junk on the bottom of the tank, but rather from running the injectors without fuel in them and cause damage from lack of lubrication and then the whole priming process which must be a nightmare on these trucks.


I guess that could be as well. I had my 2004 Cummins 2500 for 9 years and every now and then that trash in a low tank thing would be asked. It got old. I never ran it out of fuel but it got close a few times.


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## jmac5058 (Sep 28, 2009)

abbe;2058123 said:


> I don't think he is inferring that the damage will come from junk on the bottom of the tank, but rather from running the injectors without fuel in them and cause damage from lack of lubrication and then the whole priming process which must be a nightmare on these trucks.


Turning the key on and off 3 or 4 times primes them now. Long beds have the same small tank as short beds , its less than $50 to fill from empty now.


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## 1olddogtwo (Aug 6, 2007)

jmac5058;2058146 said:


> Turning the key on and off 3 or 4 times primes them now. Long beds have the same small tank as short beds , its less than $50 to fill from empty now.


Not same size.

Total cap for mine is 226gals


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## tjctransport (Nov 22, 2008)

Dogplow Dodge;2057850 said:


> *Will it improve once the motor is broken in *? With only 7k on the engine, it's not even scratched the surface, I would imagine.
> 
> His tires were a little low, so I filled them. We'll see if the trip I have to make with it, the mileage improves.
> 
> BTW, Check your PM.


with ours it went up around 2 mpg after around 10,000 miles


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## tjctransport (Nov 22, 2008)

with an in tank fuel pump, the fuel keeps the pump cool. if you constantly run the tank empty, the pump is in the air and will overheat leading to premature pump failure.


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## jmac5058 (Sep 28, 2009)

1olddogtwo;2058156 said:


> Not same size.
> 
> Total cap for mine is 226gals


They were saying a reg cab has a larger tank they dont . And I doubt you hold 226 gallons .


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## 1olddogtwo (Aug 6, 2007)

I carry two 100 gal tanks, sometimes 3 of them.

I also have a 800 gal trailer I haul around if needed.


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## Dogplow Dodge (Jan 23, 2012)

1olddogtwo;2058177 said:


> I carry two 100 gal tanks, sometimes 3 of them.
> 
> I also have a 800 gal trailer I haul around if needed.


Do you need Hazmat placards on the truck at this point ?


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## 1olddogtwo (Aug 6, 2007)

Dogplow Dodge;2058181 said:


> Do you need Hazmat placards on the truck at this point ?


Yes, but I don't unless I have the trailer.

Been carrying two tanks for years, stop more then a few times, hassled once for two. Fuel dipped more than a few times for red.


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## SnoFarmer (Oct 15, 2004)

Banksy;2057944 said:


> IMO, this don't run the tank too low thing is more myth than truth.


As the pick up is at the bottom yur always picking up from the bottom.Thumbs Up

running out of fuel is no different to the injectors than shutting if off is... running out of is hard on the turbo and your injection pump, but its the hardest on the turbo....

Ive done some research and fuel is not necessarily a coolant for a lift pump. it will last just as long if it is never submerge in fuel . most say it is not used to cool the lift pump.
you could run it at 1/8 of a tank for it's life.....its designed to be run that way....

the fuel running threw it lubercates and it may cool the pump but it does not need to be submerged. lets say for the heck of it the fuel is 75*F fuel,,,,, 100*f +- air temps... so some are saying this 25*F +- is going to cause issues?


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## tjctransport (Nov 22, 2008)

the fuel cools the in tank pump. but since most ford diesels do not have an in tank pump, that is not a problem. 
i am not sure if the 6.7 uses an in tank pump or not.


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## SnoFarmer (Oct 15, 2004)

I've read things that say that the fuel doesnt cool the pump,

It can run just fine in temps higher than diesel or gasoline Can stay a liquid at


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## Randall Ave (Oct 29, 2014)

I took a look at the Ford Parts site, saw 26, 28, and 37 gallons tanks. 
I've never gotten Fords thinking on tank capacity. 
SnoFarmer, can you explain how running out of fuel can hurt a turbo?


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## tjctransport (Nov 22, 2008)

SnoFarmer;2058720 said:


> I've read things that say that the fuel doesnt cool the pump,
> 
> It can run just fine in temps higher than diesel or gasoline Can stay a liquid at


i have read that too. but real life is a lot different than books. take two trucks or cars. run one constantly with a full tank and one constantly with an empty tank. the one that always has the fuel pump in the air instead of in fuel will burn out within a short time.


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## SnoFarmer (Oct 15, 2004)

^myth ........


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## 1olddogtwo (Aug 6, 2007)

SnoFarmer;2058859 said:


> ^myth ........


^Busters.....


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## SnoFarmer (Oct 15, 2004)

Randall Ave;2058800 said:


> SnoFarmer, can you explain how running out of fuel can hurt a turbo?


even a liquid cooled turbo needs to cool and slow down before it is shut down,

when you run our of fuel it will probably be a hot shut down, the oil flow to the bearings stops so does the flow of coolant. turbo bearings live in a very hot location.
when a hot shut down happens the bearings in the turbo take the brunt of it, building up carbon,coking, and varnish.
a few of these and your bearings are shot.

its the reason cool-down timers were invented.

in your owners manual there should be a section on cool-down times...

P14 2014 ford diesel supplement.
http://www.fordservicecontent.com/F...pplement-Second-Print_60l6d_en-us_09_2013.pdf


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## Dogplow Dodge (Jan 23, 2012)

Thanks for the link, Snow

This is what I was thinking all along (from the link you provided)


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## Dogplow Dodge (Jan 23, 2012)

SnoFarmer;2058868 said:


> even a liquid cooled turbo needs to cool and slow down before it is shut down,
> 
> when you run our of fuel it will probably be a hot shut down, the oil flow to the bearings stops so does the flow of coolant. turbo bearings live in a very hot location.
> when a hot shut down happens the bearings in the turbo take the brunt of it, building up carbon,coking, and varnish.
> ...


3-5 minutes.... which I've never done..... @ nearly 200,000 miles and counting.


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## SnoFarmer (Oct 15, 2004)

good for you...
I guess you don't work her.


the damage from hot shut downs depends on how hot it was and how often it happens...
Why would you take the risk a turbo is expensive enough. a bad turbo can lead to engine damage.

as a young equipment operator is was ingrained into me, to always let her idle before shutting down.

I also have put thousands of hrs operating diesel equipment


hundreds of thousands of miles,, and I have only replaced 3 fuel pumps all mechanical.... all mounted to the gassers block, not one electric lift-pump....
and i dont really care if its full of below 1/2 tank.:waving:


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## Dogplow Dodge (Jan 23, 2012)

SnoFarmer;2058888 said:


> good for you...
> I guess you don't work her.
> 
> .:waving:


I never said I don't let it idle. I just don't let it sit idling for 3-5 minutes.:waving:

I wait till the exhaust gasses get at or below 300" F and then shut it down. I'm not beating on the truck as I'm pulling into a stop / rest area, so the temps are generally around 500 or less as I'm putting it into park. 30 seconds or so, usually I'm below 300, then it gets shut down.


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## SnoFarmer (Oct 15, 2004)

Dogplow Dodge;2058891 said:


> I never said I don't let it idle. I just don't let it sit idling for 3-5 minutes.:waving:
> 
> I wait till the exhaust gasses get at or below 300" F and then shut it down. I'm not beating on the truck as I'm pulling into a stop / rest area, so the temps are generally around 500 or less as I'm putting it into park. 30 seconds or so, usually I'm below 300, then it gets shut down.


and that is a far cry from shutting her down to running out of fuel, what if you were working her at the time you ran out?


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## Dogplow Dodge (Jan 23, 2012)

SnoFarmer;2058899 said:


> and that is a far cry from shutting her down to running out of fuel, what if you were working her at the time you ran out?


That happened when I had a full tank. I was driving north, when my VE pump sprung a leak. Pulled over, truck died. Towed to shop, and the fixed it. No turbo issues from the event.

My brick has 6 gallons in it when gauge shows empty. Never went past empty


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