DEF Consumption Rate

[gMw]

Our 2013 Fleetwood Expedition has a Cummings ISB10, 6.7 L, and uses DEF.

I’ve seen a lot of posts about MPG. I’m wondering if anyone is tracking the DEF Consumption Rate? If so, I'd like to get your feedback on the DEF Consumption Rate your engine is getting.

Based on the reading I’ve done, my expectation was the ISB10 would consume 1 gallon of DEF for every 50 Gallons of Diesel fuel. Or a 2% consumption ratio (DEF to Diesel).

Based on actual DEF/Diesel consumption, the ratio is over 3%, so it’s using 50% more DEF than expected.

BTW: The MPG with the ISB10 started out in the upper 8’s (almost 9), but quickly dropped to about 8.1… I know a lot of factors go into figuring MPG, BUT the net result is a drop in the MPG (the 2002 CAT 3126 we traded in got 8.25 to 8.5 mpg, same length, almost the same weight, and towing the same weight).

[Maladjusted]

My DEF consumtion is about what Cummins literature states.

I used 4 gallons in 2k miles.. .500 miles per gallon. I get 10.5 Mpg, so I am about right on.

Mal

[traveler of california]

I have an older coach, therefore no DEF. I'm curious as to where you purchase the stuff and what is the cost per gallon?

Nick

[Genset]

My Cummins (2) do ot use DEF, however we do have 2 Ford 6.7 Power Stroke F350 service trucks using the DEF, they run about 800 Mlles per gal.

No idea, but guessing a different program or what ever. May be due to lighter loading, they run about 9,000 lb normal weight
.
Just guessing.
Dave M

[JMonroe]

Cummins estimated about a 2% DEF to fuel ratio and our "real world" experience shows that to be just a hair high, we use a touch less. (A gallon of DEF for every 50 gallons of diesel - using Cummin's estimate). Ours does come out very close to Malajusted's one gallon for every 500 miles, which would suggest I'm getting 10 miles per gallon, using Cummins estimate, but I'm not. My trip planning is done assuming 7 miles per gallon - thus I'm beating the 2% estimate (I'm using less DEF than the estimate).

Our engines, however, may not be representative of what you'll get with yours.

[gmadams]

Originally Posted by traveler of california

I have an older coach, therefore no DEF. I'm curious as to where you purchase the stuff and what is the cost per gallon?

Nick

Some truck stops sell DEF at the pump. I just purchased some at the pump at a TA truck stop. It was $2.89 a gallon. Otherwise you have to purchase it in 1 or 2.5 gal containers and the cost is significantly higher.

[Pigman1]

We ave a Cummins 450 ISL and my DEF use is running from 4929 to 5570 miles on 15 gal. That's 328 to 321 miles per gallon over the 15,000 miles we have on the rig. We're in Alaska now and I have to fill the DEF before we start home in Sept. Couldn't find any places that sold bulk DEF up here, So I brought mine from home in 3 5gal cans. We filled up in Ohio and Shelby, MT just before getting to Canada. PITA and we're definitely not seeing any super fuel mileage on the rig while using it. We get about 6.75 so far on a 41,000 lb rig with a 6000 lb toad.

[gMw]

Thanks for the replies...

Over 2,000 miles, our motorhome consumes 7.5 to 8 gallon of DEF, based on fuel used, I would have expected it to consume 5 gallons.

Due to the fact that our DEF Tank fill is on the right side, and all the truck stops I've been to have the DEF pumps on the left, we have only been able to buy DEF in bulk once, at a cost of $2.80 per gallon.

At truck stop 'stores', I've purchased DEF in 2.5 gallon containers at a cost of $15. Recently, I've found DEF in 2.5 gallon containers at Walmart for $11.97.

[JMonroe]

gMw, that does sound very high. I'd expect roughly 3500 miles on 8 gallons of DEF. Unless you're getting only 5mpg, which I'd think was a different problem, I think I'd talk to your chassis manufacturer about excessive DEF use.

[gMw]

Jay,

I'm taking our Expedition to Decatur the end of July. I'll have the chassis tech at Fleetwood Service look at the fuel mileage and DEF consumption issue than.

[photoguy1313]

Originally Posted by gMw

At truck stop 'stores', I've purchased DEF in 2.5 gallon containers at a cost of $15. Recently, I've found DEF in 2.5 gallon containers at Walmart for $11.97.

I encountered the same problem yesterday at a Love's truck stop - couldn't fill me DEF tank because of where the DEF dispenser was located.
I had purchased a 2.5 gallon container at Walmart, filled my tank at the time and saved the container with its dispensing hose. I refilled the container at $2.699 per gallon and will fill my DEF tank from that. This might become my standard workaround ...

Norb

[JohnBoyToo]

Be careful reusing bottles....

the def will crystalize if left to it's own devices

our ford trucks have a def heater to keep it liquid... would assume the pushers do too, but out in the air - once it sets up it will turn to crystals....

(and for a different perspective, I use the Pilot / Flying J phone app to find their def pumps - last I did it was 2.79/gal...)

[JMonroe]

gMw, you'll love camp Decatur.

Gravel parking lot with 50 amp hookups. We've spent our share of nights there. Of course the 5AM wakeup is fun too, so they can come get your coach by 6. At least the trains (running right next to the "campground") aren't too frequent.

[photoguy1313]

Originally Posted by JohnBoyToo

Be careful reusing bottles....

the def will crystalize if left to it's own devices

our ford trucks have a def heater to keep it liquid... would assume the pushers do too, but out in the air - once it sets up it will turn to crystals....

(and for a different perspective, I use the Pilot / Flying J phone app to find their def pumps - last I did it was 2.79/gal...)

Not sure what you're saying about crystallizing - do you mean in freezing temps? Or crystallizing when exposed to air? I wasn't suggesting long-term storage in the reused container, merely collecting at a fuel stop with later filling into the coach tank.

Norb