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DEF has come around to be the new Ethanol "Get rich" scheme..

The EPA raises its standards on emissions so that means more DEF usage and more $$ from the Consumer...
I'll gladly pay for higher DEF consumption and less EGR!!. That's what mfg are doing to control NOx emissions. Net is a win for users with less EGR. DEF is cheap, doesn't have the negative effects on mileage, contamination that EGR does.

IMHO it's not anywhere near the boondoggle that Ethanol is. It actually is a good solution to a problem.
 

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Greetings from the Florida Panhandle

I just traded the '18 Dmax for a 2020. I am super glad to have the DEF filler in the Fuel door. With only 600 miles, I don't have any DEF use figures yet, but I do have a question for the group. I just read in the 2020 manual that I should not "top off" the DEF tank. I have had an '11 and an '18 and many times topped off the DEF tank. Was I doing it wrong all these years?

Brian
 

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I just traded the '18 Dmax for a 2020. I am super glad to have the DEF filler in the Fuel door. With only 600 miles, I don't have any DEF use figures yet, but I do have a question for the group. I just read in the 2020 manual that I should not "top off" the DEF tank. I have had an '11 and an '18 and many times topped off the DEF tank. Was I doing it wrong all these years?

Brian
Congrats on your new purchase. be sure to update your signature info

:thumb:
 

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I just traded the '18 Dmax for a 2020. I am super glad to have the DEF filler in the Fuel door. With only 600 miles, I don't have any DEF use figures yet, but I do have a question for the group. I just read in the 2020 manual that I should not "top off" the DEF tank. I have had an '11 and an '18 and many times topped off the DEF tank. Was I doing it wrong all these years?

Brian
You’re not supposed to “top off” your fuel tank either, but if you do, are you doing it “wrong”?? They just don’t want you spilling it, and when the DEF freezes, if you’re in a cold climate, it needs a bit of room for expansion.
 

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I just read in the 2020 manual that I should not "top off" the DEF tank. I have had an '11 and an '18 and many times topped off the DEF tank. Was I doing it wrong all these years?
Brian
No need to worry about prior years not unless you still own them. I’m sure they had there own filling recommendations in the Owners Manual.
 

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anybody have any bulliten numbers for the def updates that people say have been done?
 

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When any dealer runs your VIN they can/should do an inquiry to see if it has any updates that haven't been applied.
 

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2800 miles on mine and I had to add 5 gallons to top of the DEF tank.
 

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My DEF gauge was showing 1 bar remaining. I had 3919 miles on the tank. It took 5 gallons when the pump clicked off. I did not try to add any more after that. I don't know how full the dealer had it when I go it. Unfortunately I had not been able to tow my camper yet. My over all mileage has been 16.9mpg that is with all purchases entered in an excel spread sheet. That is about 800 miles to the gallon of DEF. When I tow and my mileage will be quite a bit less that ratio will not be so favorable. On my 2015 LML I was pretty close to 1000 miles per gallon of DEF even with towing tossed in.
 

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Is there an update from the dealership I need to have done to my truck in reference to DEF usage? I have just over 3,000 miles on mine. I went through 5 gallons of DEF at about the 2700 mile mark.
 

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Greetings from the Florida Panhandle

I just traded the '18 Dmax for a 2020. I am super glad to have the DEF filler in the Fuel door. With only 600 miles, I don't have any DEF use figures yet, but I do have a question for the group. I just read in the 2020 manual that I should not "top off" the DEF tank. I have had an '11 and an '18 and many times topped off the DEF tank. Was I doing it wrong all these years?

Brian
Moosetags, the new DEF fill location is so nice. About time they put it in a logical location. So many great features on the new 2020's. My wife, who was not a big fan of me selling my 2017 DMAX, agrees that the new truck is that much nicer. These things are a towing beast. Love it
 

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OK Dually is correct, according to a friend in GM fuel programming, emissions requirements changed and targets for NOX are now stricter than they were when DEF NOX control was first introduced. This means greater DEF consumption to achieve the new targets for NOX, along with more frequent, but shorter, regeneration cycles. Following a regen, DEF injection is used to help cool the SCR, so that uses even more fluid. I think it might be the same people managing NOX emission standards who are managing the Wuhan Virus lock downs.
 

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OK Dually is correct, according to a friend in GM fuel programming, emissions requirements changed and targets for NOX are now stricter than they were when DEF NOX control was first introduced. This means greater DEF consumption to achieve the new targets for NOX, along with more frequent, but shorter, regeneration cycles. Following a regen, DEF injection is used to help cool the SCR, so that uses even more fluid. I think it might be the same people managing NOX emission standards who are managing the Wuhan Virus lock downs.
Is you buddy giving an updated '% of fuel' number that should be expected?

GM published a number when the LML was introduced.

Knowing what % expected can certainly hep identify if one is 'overusing' or if it is the common gauge/was it filled problem that has existed since def was introduced.
 

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Diesel Exhaust Fluid Consumption
May 21, 2020
The diesel engines (RPOs LWN, LM2, L5P, L5D) available on 2020 Colorado, Express, Silverado 1500, Silverado 2500HD/3500HD, Silverado 4500HD/5500HD/6500HD, Canyon, Savana, Sierra 1500, and Sierra 2500HD/3500HD models use Diesel Exhaust Fluid (DEF) (Fig. 1) in order to reduce the exhaust Oxides of Nitrogen (NOx) levels within the Selective Catalyst Reduction stage of the exhaust aftertreatment system. A series of driver prompts and warnings are initiated when the DEF level falls below a calibrated value.

Fig. 1

Segmented DEF Level Gauge
The current 2020 Silverado 1500 and Sierra 1500 models have a DEF level gauge on the instrument cluster that provides drivers with a representation of how much DEF is in the DEF tank up. (Fig. 2) The DEF level gauge does not operate like a typical float-style gauge that is used in a fuel tank. The Engine Control Module (ECM) monitors the DEF level and consumption rate in order to calculate an estimated range. DEF levels are detected by the DEF level sensor.

Fig. 2

There may be some fluctuation in the amount of DEF represented on the DEF level gauge. After filling the DEF tank, it may take a few key cycles to register the correct amount in the DEF tank. With the new segmented DEF level gauge, it is possible that after adding 5 gallons (18.9 L) of DEF that the gauge reads as a full tank after the fill event. However, if the actual level of DEF is just entering the last segment on the gauge, the gauge is likely to drop by one segment shortly after driving after the fill event. As a result, a driver could have an initial impression that the vehicle consumes an excessive amount of DEF.
Emissions Requirements
Every year, GM produces diesel engines that continue to meet aggressive federal requirements to reduce Nitrogen Oxides (NOx) in the vehicle exhaust. As DEF is required to reduce the NOx in the exhaust, DEF consumption will increase as NOx reduction requirements increase. Customer trading in an older model year diesel vehicle for a newer model year vehicle will likely see an increase in DEF usage. DEF consumption increases as the newer vehicles meet the more stringent emission requirements for that model year.
The amount of DEF consumed also is a function of how hard the engine is working, or engine load. Due to engine use, it is more representative to compare DEF consumption to the amount of fuel consumed – also a function of engine load – instead of miles traveled. In addition to engine load, other factors that affect the DEF usage rate are the humidity, temperature, and altitude where the vehicle is operating.
Under certain conditions, the ECM will increase or decrease the amount of DEF used based on learning or adaptive algorithms. In the event of a malfunction and Check Engine light, the ECM may double or even eliminate the amount of DEF that is being used. An improper amount of DEF use will continue until the vehicle is repaired and the learned value in the ECM is reset.
 

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Is you buddy giving an updated '% of fuel' number that should be expected?

GM published a number when the LML was introduced.

Knowing what % expected can certainly hep identify if one is 'overusing' or if it is the common gauge/was it filled problem that has existed since def was introduced.
Can't get an official number tied down. Too many variables affect DEF usage as per some of the comments already made, e.g. frequency of regens, how hard the truck is driven, exhaust gas temperatures. My 2019 uses noticeably more DEF than the 2017, but I haven't kept an exact log so I can't post any numbers.
 

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Thanks for the GM Tech link. I filled my DEF tank up and the gauge did not read full. I will give the truck one or two more key cycles and see if it corrects itself.
 
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