Jump to content

3.0 Duramax DEF consumption

Firetrout
 Share

Recommended Posts

Firetrout Enthusiast

Firetrout

Posted
Posted

What are yalls thoughts on DEF consumption?  I have 9400 miles on mine and have added 15gal so far and am at half tank right now.  80% of driving is hwy. Thoughts?

  • Replies 108
  • Created
  • Last Reply

Top Posters In This Topic

Popular Days

Top Posters In This Topic

Popular Days

Popular Posts

Chrisd534
Chrisd534

3000 on mine and only one notch of the DEF bar gone. 

becker87
becker87

I have about 10,000 miles on mine. Probably just over two tanks of DEF. Minimal towing and hauling but mainly rural roads and around town Sent from my Pixel 2 using Tapatalk

davidr83
davidr83

When I got mine (Feb. 27th), it had less than 10 miles and the def was about half full. I had to fill the def(2.5 gals) up at about 2300 miles and it's still showing the same amount of def since then

Posted Images

yousaveone Enthusiast

yousaveone

Posted
Posted

Mostly highway no towing, I burn 1 gallon per 1000 miles. The manual says if you tow it will use a lot more fluid. How much weight do you have in the truck?

redwngr Senior Enthusiast

redwngr

Posted
Posted

Do you know that it was full at the start of the 9400 miles? 

I don't have much faith in the def gauges other than to get a guestimate.

 

What is you average fuel mpg over those miles?

 

DEF is used whenever a diesel is running. Use is proportional to fuel used. More fuel requires more def.

GM published that they expected the 6.6 to use about 1.5 to 2 gallons of def per 100 gallons of fuel (1.5 -2 % of fuel usage). 

 

If 3.0 ratio is the similar, then expected def can then be worked out from average fuel usage.  

 

9400 miles at 25 mpg 

9400/25 = 376 gallons of fuel

2% = 7.5 gallons of def.

 

 

 

 

 

 

 

srqG8 Enthusiast

srqG8

Posted
Posted

Going by my DEF gauge (FWIW), I’ve used about 1.5gal (if each “bar” is worth 0.5 gal like I think I read in the diesel owner‘s manual insert). About 4200 miles on the odo, avg 25 MPG over those miles. If this helps: No towing yet, 60% hwy/40% city, very little idling. 
 

Haven’t added any DEF yet, but will soon. 

  • 2 weeks later...
wizard4878 Enthusiast

wizard4878

Posted
Posted

sounds really high to me.  I drive a semi getting 6mpg and only need about 4 to 5 gallons a week.   using that much I would think your dpf is close to being plugged up.  I'm just going off my experience with 13 and 15 liter Diesels though,  so take it for what its worth...

Matt076 New Member

Matt076

Posted
Posted

I tow a 5000 lb. snowmobile trailer to Michigan and back. The trip is roughly 1100 miles round trip and I use between 15 and 20 gallons. What could the problem be? Sometimes the 500 mile warning will come on when I still have a half tank of fuel left and I fill them up at the same time. If this is normal then I need a bigger def tank or a bigger bed to haul fluid in . lol I am not a happy camper by any means. Goes to the dealer again tomorrow. However they really have no insight into this issue! 

 

  • 2 months later...
becker87 Senior Enthusiast

becker87

Posted
Posted

I have about 10,000 miles on mine. Probably just over two tanks of DEF. Minimal towing and hauling but mainly rural roads and around town

Sent from my Pixel 2 using Tapatalk

  • Like 1
Chrisd534 Enthusiast

Chrisd534

Posted
Posted
On 4/11/2020 at 12:12 PM, ChuckTaylor said:

How is the DEF usage looking on these trucks now?

3000 on mine and only one notch of the DEF bar gone. 

  • Like 3
davidr83 Enthusiast

davidr83

Posted
Posted

When I got mine (Feb. 27th), it had less than 10 miles and the def was about half full. I had to fill the def(2.5 gals) up at about 2300 miles and it's still showing the same amount of def since then and I'm a little over 2650 miles now. 70% highway/30% city driving usually running 5-10 over the speed limits and have not towed anything but did have the bed full of stuff a couple times.

  • Like 1
LaRed Enthusiast

LaRed

Posted
Posted (edited)

Bought late January. I have 5700+ mi on mine. DEF tank full when I left the dealer.  First 4300 mi. DEF gauge showed 1/2 tank remaining. No towing practically all highway mi.  Thought I should have plenty to make a 1250 mi trip home from FL pulling my 20 ft Flats boat based on history.  After 200mi. DEF warning 1000 mi remaining still only 1 bar under 1/2 tank. 2 1/2 gallons of Blue DEF from WalMart put it back to 1 bar under full.  50 mi from home warning came on again.... 265 mi. remaining. This was shocking. Another 2 1/2 gallons of Blue DEF from WalMart put the gauge back to 1 bar under full. 

So..... not sure how much I'm burning. But I do expect the gauge to be more accurate. This does seem to be excessive to me. Maybe its not. Based on the gauge it seems certain I burned at least 2 1/2 gallons in 1000 mi. while pulling the boat. 

Overall fuel mi including the tow home 21.3. Towing the boat only ..15.1 for the 1250 mi. trip to NW Arkansas. Overall before towing 22.7.

Edited by LaRed
  • Like 1
topgear1224 Enthusiast

topgear1224

Posted
Posted

I have 2400 miles and showing 180miles remaining...... Def is 15.28/ GALLON up here.......

That's .04/mile in DEF. Or based on my 24mpg avg and extra 0.96 per gallon of fuel used.....

Diesel is $2.70 +$0.96 in DEF.

This damn thing is $3.66/gallon to go 24 miles.
15.25¢ per mile....

The 6.2L is 12¢(19mpg combined) per mile WTH.

Dealer told me should only need filled when the oil is changed.....

Sent from my SM-N975U using Tapatalk

steve841 Enthusiast

steve841

Posted
Posted
48 minutes ago, topgear1224 said:

I have 2400 miles and showing 180miles remaining...... Def is 15.28/ GALLON up here.......

That's .04/mile in DEF. Or based on my 24mpg avg and extra 0.96 per gallon of fuel used.....

Diesel is $2.70 +$0.96 in DEF.

This damn thing is $3.66/gallon to go 24 miles.
15.25¢ per mile....

The 6.2L is 12¢(19mpg combined) per mile WTH.

Dealer told me should only need filled when the oil is changed.....

Sent from my SM-N975U using Tapatalk
 

 

You're either paying too much or messed  up your math.

 

DEF is around $15.00 per 2.5 gallons.

topgear1224 Enthusiast

topgear1224

Posted
Posted
 

You're either paying too much or messed  up your math.

 

DEF is around $15.00 per 2.5 gallons.

Have to use ACDelco fluid from the dealership otherwise the dealer will not submit any DEF claims under warranty when everything fails because it gets to -40 degrees out here. Going form a 70 degrees humid garage (from ice melting) to -40 causes condensation in the DEF tank.

 

 

15.28/gallon here. 26.55/ 2.5 gallons.

 

Using the per gallon to cover labor.

 

If you have an issue without a service ticket your SOL.

 

2 L5P last winter went through $6k in out of pocket repairs each at 5k miles dealer claims it was because of the supertech fluid being contaminated with water. dealer called GM. GM asked if they use genuine fluid dealer said no and GM said they're not covering anything. apparently there is a bulletin out that states that any 2007 and newer Duramax must use AC Delco genuine fluid.

 

Sent from my SM-N975U using Tapatalk

 

EDIT: BULLETIN DOES NOT OFFICIALLY EXIST.

 

 

 

 

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share
Go to topic listing

  • Latest Articles

  • Posts

    • newdude
      Gas fill door

      By newdude · Posted

      Common failure.  You need to replace the fuel door housing.   The painted cover transfers over to the new housing.  To remove the old one there is 4 spots where you poke the plastic to release it.  
    • newdude
      Gasser Subforum Has Been Quiet - - So, Regenerative Braking and Using L10

      By newdude · Posted

      No such thing as regenerative braking on a pure ICE vehicle.     Regenerative braking is the re-capture of energy from electric motors and stores it in the battery pack.  So hybrids, PHEV and EVs have regenerative braking.     What you are seeing is the charging system changing modes is all.  Its likely entering charge mode for some sort of reason is all.  All of the charging modes will be listed below.   As for L10 vs D.  L10 turns off automatic grade braking.  L10 puts you in control of grade downshifts where in D it will automatically do it based on brake pedal position and other factors.  Otherwise L10 and D drive exactly the same aside from that one aspect.    Battery Sulfation Mode The BCM will enter this mode when the interpreted Generator output voltage is less than 13.2 V for 45 minutes. When this condition exists the BCM will enter Charge Mode for 2–3 minutes. The BCM will then determine which mode to enter depending on voltage requirements.   Charge Mode The BCM will enter Charge Mode when ever one of the following conditions are met:   Windshield wipers are ON for more than 3 s. Climate Control Voltage Boost Mode Request is true, as sensed by the HVAC control module via serial data. High speed cooling fan, rear defogger, and HVAC high speed blower operation can cause the BCM to enter the Charge Mode. The estimated battery temperature is less than 0°C (32°F). Battery State of Charge is less than 80%. Vehicle speed is greater than 145 km/h (90 mph) A current sensor malfunction exists. System voltage is determined to be below 12.56 V When any one of these conditions is met, the system will set targeted generator output voltage to a charging voltage between 13.9–15.5 V, depending on the battery state of charge and estimated battery temperature.   Fuel Economy Mode The BCM will enter Fuel Economy Mode when the estimated battery temperature is at least 0°C (32°F) but less than or equal to 80°C (176°F), the calculated battery current is less than 15 A and greater than −8 A, and the battery state-of-charge is greater than or equal to 80%. Its targeted generator output voltage is the open circuit voltage of the battery and can be between 12.5–13.1 V. When fuel economy mode is active, the generator is not charging, only maintaining open circuit battery voltage. The BCM will exit this mode and enter Charge Mode when any of the conditions described above are present.   Headlamp Mode The BCM will enter Headlamp Mode when ever the head lamps are ON (high or low beams). Voltage will be regulated between 13.9–14.5 V.   Start Up Mode When the engine is started the BCM sets a targeted generator output voltage of 14.5 V for 30 s.   Tow/Haul Mode (if applicable) Pressing the Tow/Haul Mode button located on the center stack, the vehicle system voltage is raised and the remote (non-vehicle) battery will be charged. Having the headlamps on will raise the system voltage and if the Tow/Haul button is applied it will not serve any purpose. The voltage is regulated between 13.9-14.5 V.      
    • jaszr2
      Active Grille Delete

      By jaszr2 · Posted

      Hello from Australia Just sharing that there is now a way to delete the active shutters entirely with just a plug in module. Opens up tons of room to light bars etc.
    • jake111
      Gasser Subforum Has Been Quiet - - So, Regenerative Braking and Using L10

      By jake111 · Posted

      I have an observation and a question... 1) I watch the voltage closely because I have had to dial in the cut-in/cut-out voltages of the battery separator to my camper.  The "smart" charging drives me nuts.  Anyway, I noticed that when coasting for a while, and especially if lightly using the brakes (though not necessary), the voltage goes up from mid/high-13 volts to mid/high-14 volts.  Then it drops back down after stopping or going again.  Consistently!   The only explanation I can come up with is REGENERATIVE BRAKING!  Well, maybe that's a little bit of an exaggeration, but it's certainly free extra battery charging.   2) Driving on mountain roads I will use L and vary the max gear.  Things straighten out and I end up in L10.  Sometimes I leave it there for a while.  Is there any difference between L10 and D?   
    • devonthegreat
      anyone interested in a 2002 Chevy Silverado 4x4 parts truck NYC

      By devonthegreat · Posted

      **SOLD** Please end or delete post. thank you

  • GM-Trucks.com Clubs

  • Popular Contributors

×
×
  • Create New...