The update docs suggesting adding def at the 5000 mile mark if you have not had a message.

The truck is expected to use def at a rate of 1 to 1.25% of fuel usage. Mileage will be a function of how hard the truck works, just like fuel is.

 

I'm right there with ya. I'm at 5000 almost to the mile and I haven't seen any DEF lights. I have DEF in the garage, I may just fill the tank for the hell of it, just so it isn't sitting around.

 

Mine went 7400 miles before the warning.
When it did come up, it said that I had 298 miles to go.
Had a jug in the garage waiting for the warning.
It took a few minutes driving for the warning to leave once I added.

 

The 1000 mile warning clears by itself so it would be easy to miss.
Other than that it sounds like yours is working as it is supposed to.

That's about 1500 miles per gallon. Did you have any towing? How heavy?

DEF is supposed to be 1 to 1.25% of fuel usage. That would suggest you're averaging about 15mpg overall. Does that make sense with what you've been seeing/calculating?

 

This is good stuff. I just flipped 5,000 miles and no warning. I was starting to get a little worried. Think I'll do the same and fill my DEF tank this wekend.

 

I just put DEF in mine at 5900 miles and never saw a warning at all. I just knew I would be doing a lot of driving and didn't want to carry the jugs in my truck waiting for a warning!

 

I now have 17,000 miles on my 2011 Duramax, and I have never seen a light or a warning on the DIC. I have asked the Dealer to verify that the DEF level indicator was working on my truck and he sent me the GM web video to watch! There is a rumor that some of the early builds were sent out without the level indicators installed! I have put 5 gallons in over the time that I have had it because I was afraid of voiding the warranty. I advised the dealer I would not add anymore until the light or the DIC came on! I told him I would call back at 20,000 miles and see what they advise then!?!? My truck goes back in the shop next week for the 7th time to try and fix the smoking out from under the engine due to another problem with my truck that is nicknamed "Smokey" by my kids and co-workers!

 

Maybe the dealer is sneaking some in on your visits for the downpipe issue.

 

I have almost 4500 miles on mine and just returned last night from a 1000 mile trip (600 of towing our 14k 5th wheel) and have not got any warnings on mine either. I brought 2 gals. with me just in case I got the warning while gone, but nothing.

 

4300 miles and nothing so far. I carry a gallon around in the tool box just in case though. I am going to take it in for service at 5000 and get it topped off anyways.

 

Mine's at 5800 miles. At 5400, no warnings, so I went ahead and topped it off. I figured it would be low, so I bought 4 1/2 galons (all the the auto store had on hand). I could only get 3 1/2 galons in.

 

I've been putting a gallon in every 1,000 miles, but that's only been twice since we are not yet to 3,000. I think it will be interesting to see how many miles are on it when the low alert comes on. Not yet keeping a spare and funnel in the truck, but probably a good idea to do so.

 

Some def brands are packaged with a flexible screw-on tube so you don't need a funnel.

 

336 miles on mine, I hope because it was special ordered and finished on jan 31 that it has a the fix already in it. We will see

 

You may have a trouble-free truck (lots do) but there have been several updates addressing the def issue since Jan 31.

 

A newbie here with a question regarding DEF. At 3,000km my 1600km warning came in and since I was off to Florida I topped up. However near Louisville KY the truck was restricted to 80km/hr anyways. A GM dealer there downloaded some software to clear my alarm and I have not had an alarm or warning and am at 16,000km. I figure I must be empty and am wondering, does running with no DEF harm the truck in any way? Thanks Dave

 

Dave, your truck will not let you run empty.

The Louisville dealer probably performed the def reset update procedure (do a search on this site for lots more info - both good and bad). They should have filled the def tank as part of the procedure. Def consumption is often 1200 - 1500MPG. With the 5.3 gal tank your truck could be operating normally and be very near getting the def refill warnings.

 

I just took my truck on a 2000mi trip i was about 75mi from being home when the def message came on,saying that I had 298mi left, now at 8000mi i had the oil change and had the def tank filled so im now comming up on 1300mi so that make about 5000 mi i went on, and i did a lot of pulling heavy load driving 70 to 80 mph.. now i thought the def notice came on at 500 mi but it was so fast that i didnt catch it. however when it said that I had 298 miles to go and it was counting down fast, I drove 5 miles down the road and then it said i had 287mi so I just pull over and put in 2 gallons in it start the truck back up and with in 30 sec it reset itself.. I DO WISH THEY WOULD OF PUT A GAUGE INSIDE THE TRUCK TO WATCH THIS, THIS WAS VERY STUPID TO NOT PUT ONE IN. Im going to make mine own so I know how much is in it at all time and then I will sell it to GM

 

I just took my truck on a 2000mi trip i was about 75mi from being home when the def message came on,saying that I had 298mi left, now at 8000mi i had the oil change and had the def tank filled so im now comming up on 1300mi so that make about 5000 mi i went on, and i did a lot of pulling heavy load driving 70 to 80 mph.. now i thought the def notice came on at 500 mi but it was so fast that i didnt catch it. however when it said that I had 298 miles to go and it was counting down fast, I drove 5 miles down the road and then it said i had 287mi so I just pull over and put in 2 gallons in it start the truck back up and with in 30 sec it reset itself.. I DO WISH THEY WOULD OF PUT A GAUGE INSIDE THE TRUCK TO WATCH THIS, THIS WAS VERY STUPID TO NOT PUT ONE IN. Im going to make mine own so I know how much is in it at all time and then I will sell it to GM

I'm hoping SOMEONE comes up with a gauge.

 

After I had a recal done at 13K miles I have never had a light. at 6K I went ahead and filled it and it was close to empty. This time I have 9K since fill and no light. I'm going to try and get it in this week for another cal.

Greg

 

Take your truck in to dealer. They need to do a re-learn for your DEF chip. Once they did mine, I haven't had any problems. They even filled my DEF tank up for free.

But I agree---why GM didn't give us a guage for the DEF is beyond me. I'm sure it will come out on the 2012 truck.

 

Found out some interesting information yesterday at a training session and that is that DEF fluid does not have a great shelf life. Refractometers are available for DEF and at least for the big rigs that are using DEF fleet shops have increasingly been having to use one to make sure that the fluid is good. Any word on shelf life of urea?

"To ensure the proper operation of the SCR system, operators must ensure the DEF in their vehicle consists of a 32.5% Urea / Water solution."

 

Thanks for the replies folks but I also disagree. I may be wrong but after 13,000km, just going by the sound of knocking on the tank, which I know is not a great indicator, but I believe I am running empty too. So my original question still stands. Do you think it causes any harm to the exhaust system running on empty? Dave

 

IMHO I think the DPF will plug sooner. The reason I think this is I have always gone around 600 miles between regen. The last 2 tanks I have gotten 2 regens for each tank. Regen cycle is going off of DPF pressure differential. If it is going through regen more often and I know I'm out of DEF then then it only stands to reason that DEF makes a difference.

Greg

 

is 2011 the first year of the DEF fluid?

 

Yes

 

I love my Durmax from my first 2001 model to the 2011 however the most stupid thing GM did was add this junky DEF tank..no gauge and i do tap on it to see if it getting empty.plus mine is a 4 wheel drive now you would think that GM would of put a skid pan under the Def tank that another thing im going to make for mine. BUT I STILL LOVE MY TRUCK.

 

I don't think it was "GMs idea" to go with the DEF. More like pollution requirements. I have not seen a single issue with the tank being damaged. I would also like to see a gauge.

 

Ive got 11350 mi. And no warning at all. Today i got scared and put 5 gal in it. I was going to run it until the light came on but got worried. I stay on the road too much.