# How much DEF does this car use?!



## johnmo (Mar 2, 2017)

I'm going roughly 5500 to 6500 miles between DEF refills.

I'm at 43,300 miles today and I've added a total of 19.7 gallons of DEF, but that excludes whatever it came from the factory with and whatever the dealer added at my two free oil changes.


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## Taxman (Aug 10, 2017)

johnmo said:


> I'm going roughly 5500 to 6500 miles between DEF refills.
> 
> I'm at 43,300 miles today and I've added a total of 19.7 gallons of DEF, but that excludes whatever it came from the factory with and whatever the dealer added at my two free oil changes.


Cummins says 50:1 dieselEF. 
You're closer to that than Barry seems to be.


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## boraz (Aug 29, 2013)

Taxman said:


> Cummins says 50:1 dieselEF.
> You're closer to that than Barry seems to be.


lately in my kw, im 20l def per 400l fuel, but ive been idling alot lately too


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## IndyDiesel (May 24, 2015)

Wow they sure changed def consumption from the gen 1, I can go 20000 miles on a full tank of def in my 15 CTD, and the gen 2 is more fuel efficient.


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## Barry Allen (Apr 18, 2018)

OK, I figured out what one problem was. 

It surprised me that I'd have an oil change at 7,375 miles and then be down to 28% DEF when passing 9,000 miles. When looking at the work order from the dealership oil change I looked up the part number of the exhaust fluid. The technician poured 1 gallon into the tank (should have taken over 2 gallons to completely fill the tank) and quit after that.

I can't tell if that's being cheap, lazy, or both.


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## IndyDiesel (May 24, 2015)

I would say cheap and lazy, every time I had def added with my freebies they topped off and one time gave me the rest of the remaining 2.5 gallon container that they didn’t use.


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## Barry Allen (Apr 18, 2018)

This was the same dealership where the technician thought the DEF tank was in the trunk, in the spare tire well. The technician removed everything from the trunk of my car (some diving gear, a couple firearms, other miscellaneous items while I was there on vacation) only to apparently find out the DEF tank filler was behind the fuel filler door.


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## Newbiecruzer (Nov 11, 2017)

I've been seeing about 2400 miles /gallon of DEF. My dash display starts giving me % displays at 35% - Deliberately letting it get down to 24% allowed me to just squeak in a whole 2.5 gal bottle of DEF. 
FWIW - I just finished an all-expressway trip to the Thousand Island area of NY from lower Mid Michigan - got 61.3 mpg using the odo and pump figures for 1 tank. 
Around home which is rural 2 lane and small towns - I average low 50's mpg. 
This is a '17 Diesel with 6MT - I love it - shift when I want - no start-stop to mess with.


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## HondaTech2016 (Apr 20, 2017)

I'm getting about 3500 miles before the 35% trigger shows up. I usually have to put in 2 gallons at that point, with me having to "top off" the last little bit 

If I wait till 24% I can put in 2.5 gallons, which is about 4,000 miles. I've decided to do this now because I can get a 2.5 gallon jug and not worry about having any left over.


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## DarylB (Feb 3, 2011)

I topped my def off at 1000 miles after getting the car home from the dealer (650 mile drive back home after pickup). I think it held a little over a gallon. Compared to my 6.7 cummins this car doesn't seem to use it very much. 500 miles per gallon towing heavy in the big truck.


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## firehawk618 (Feb 24, 2013)

I'd like to point out to those that are taking the % of def left as accurate.

There's no actual conventional sending unit in the DEF tank.

It can approximately sense 3 levels. That's it.

In other words there's 3 switches that activate at different levels. No float / sending unit.

Any % shown is just a best guess estimate.

My car initially would show 100% def and count down. After updating the BCM software via flashing it now the DEF just says OK like most of yours.


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## 6speedTi (May 18, 2018)




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## 6speedTi (May 18, 2018)

According to my Bluedriver diagnostic live readout the average programmed consumption of DEF is 0.02% per gallon/hour.


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