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DEF requirements


malibu2004

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I have a 17' 3500HD Duramax and to be honest, I've mostly used the Wally World SuperTech DEF.  I researched this a lot and found two main criteria to follow.  1. Must meet ISO 22241 and 2. Get fresh DEF fluid and not something that's been on the shelf for months.  I originally thought it was "too cheap" so I was using Peak Blue but the last time I used it, the box had so much dust on top of it that I grabbed the SuperTech instead and haven't looked back.  I track mileage very closely as to when DEF is added.  I only add 2.5 gallons when the computer gets to 25% as this isn't my daily driver so I don't want it sitting longer than it has too.  I average 1000-1100 miles per gallon but if I'm driving that truck, it's usually hauling the RV or boat so that mileage is mainly based on towing.

If I had regular access to bulk def at a truck stop, I wouldn't hesitate to go that route but it's not widely available around me and the places that it is don't give the perception of high volume stations so no telling how long the def has been in the tanks.  

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All DEF is the same.  They all contain the same amount of urea which is what is used to create the chemical reaction.  I am sure you can find the reg where the EPA mandates the formulation.  

Look at section three in a SDS:

http://www.usadefllc.com/uploads/USA DEF - Safety Data Sheet.pdf

https://peakauto.com/wp-content/uploads/2017/01/BlueDEF-Diesel-Exhaust-Fluid.pdf

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Go to a high volume truck stop and fill up from their pumps in bulk. That gives you three advantages. Lowest cost per gallon a full tank without over filling and freshest DEF possible. 

Edited by RyanB
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Try not to let the tank stay below 1/2 full for very long. Pour some DEF fluid on your driveway and see what it does when it dries out. Letting it dry out and crystallize in the tank is what usually causes the DEF tank heater or the level sensor go out (most common DEF related failure on a Duramax). DEF fluid has expiration dates on the jug or box, make sure it isn't expired.

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Don't want to derail, but what does that stuff really do? If you forget to add it, will the engine blow? A truck guy told me it was deer pee and I laughed but he may not have been far off, lol.

Steve B.

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1 minute ago, Steve B. said:

Don't want to derail, but what does that stuff really do? If you forget to add it, will the engine blow? A truck guy told me it was deer pee and I laughed but he may not have been far off, lol.

Steve B.

It’s urea based, so pee is kinda close. 
 

It helps reduce diesel emissions. Used during the emissions test, so the truck is programmed to disable itself if you run out. 

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The below is plagiarized, but a good summary.  Most computers know if you run out and put you into some sort of limp mode.  The engine itself doesn’t care as it is all on the exhaust side of things.  
 

DEF fluid consisting of urea and deionized water in a 1:2 solution. It’s contained in a reservoir separate from the fuel tank and is metered into the engine’s exhaust stream to control certain emissions. Inside the exhaust pipe, the DEF vaporizes and decomposes into ammonia and carbon dioxide. Those two compounds then react with oxygen and detrimental nitrogen oxides inside the vehicle’s selective catalytic reduction (SCR) catalyst. This produces three benign tailpipe gases: nitrogen, water vapor, and carbon dioxide.

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10 hours ago, hethj7 said:

The below is plagiarized, but a good summary.  Most computers know if you run out and put you into some sort of limp mode.  The engine itself doesn’t care as it is all on the exhaust side of things.  
 

DEF fluid consisting of urea and deionized water in a 1:2 solution. It’s contained in a reservoir separate from the fuel tank and is metered into the engine’s exhaust stream to control certain emissions. Inside the exhaust pipe, the DEF vaporizes and decomposes into ammonia and carbon dioxide. Those two compounds then react with oxygen and detrimental nitrogen oxides inside the vehicle’s selective catalytic reduction (SCR) catalyst. This produces three benign tailpipe gases: nitrogen, water vapor, and carbon dioxide.

Great summary.....

All the exhaust stream treatment on modern diesels is expensive, too.  You're 100% right, too.  The engine could care less about DEF.  That's why a lot of guys perform delete operations after the warranty expires.  There's a shop around me that specializes in that type of treatment on modern diesel powered trucks.  His shop is always super busy, too.  

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Yeah, I believe I read in my ram manual if you run out of def...which is difficult to do as it tells you you’re getting low similar to the fuel alert... it limits you to 55 mph for x amount of miles. Then will disable the truck if you continue without. Pretty sure duramax is similar.
“Deleting” a newer duramax is difficult to find the needed equipment and expensive since the crack down on regulations a few years back. Most diesel shops, around here anyway, won’t delete your truck due to the heavy fines they face if they get caught.

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3 hours ago, BlindSquirrel said:

Yeah, I believe I read in my ram manual if you run out of def...which is difficult to do as it tells you you’re getting low similar to the fuel alert... it limits you to 55 mph for x amount of miles. Then will disable the truck if you continue without. Pretty sure duramax is similar.
“Deleting” a newer duramax is difficult to find the needed equipment and expensive since the crack down on regulations a few years back. Most diesel shops, around here anyway, won’t delete your truck due to the heavy fines they face if they get caught.

Exactly the same here.  I would love to get my truck deleted but those that offer it have sky rocketed.  Buddy has same truck as me but three years older and deleted and it's amazing the power he has and mileage he gets.  I'm happy with what I have and what I get but there's always that concern in the back of my head about EPA related parts on these trucks.

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On 1/13/2021 at 11:17 AM, malibu2004 said:

I have a 21 Duramax and need to put in the first round of DEF. What are you guys running in your trucks? I would assume as long as it's approved it would fine. 

There was an issue with the '15 LML series where the sensor in the tank didn't like the non-GM DEF for a quick minute. There was a firmware update to fix that. A friend bought a '15 Sierra in early '15 and it triggered a code, I bought my truck in October/November (I don't remember exactly) and never had a problem with any DEF. The dealers all did firmware updates as part of the scheduled maintenance to "fix" the sensor/code issue. I've run Peak for almost every refill other than when the dealer would fill it for me. I rarely go in to WalMart so I'll have to look at the price on the SuperTech DEF the next time I'm in there.

I have an Edge CT2 on my dash (there is a 6mm bolt in the grab handle that I put a RAM ball on to mount it so I don't have to use the suction cup) the difference between the "Full" on the dash and the percentage on the CTS2 is dramatic. The truck runs off what the dash says, but it seems "Low" is triggered around 35-40% in the tank, maybe to avoid the crystallization issues mentioned previously. 

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1 hour ago, wedge88 said:

Exactly the same here.  I would love to get my truck deleted but those that offer it have sky rocketed.  Buddy has same truck as me but three years older and deleted and it's amazing the power he has and mileage he gets.  I'm happy with what I have and what I get but there's always that concern in the back of my head about EPA related parts on these trucks.

I deleted my 15' PSD about two years ago.  Did it myself for about $900 in parts (race pipe, No Limit EGR delete and SCT Tyrant tunes) and it was the best thing I ever did for the truck.  Yeah, I will admit that the unfiltered diesel smell is unpleasant but I don't smell it in the cab nor do I stand outside my truck when running.  I got really tired of the issues and "limp mode/ shut down" messages for no apparent reason other than the dealer having to complete a manual Re-Gen.  When I did have a repair item come up I was looking at $1,000 bucks to replace the DEF reductant pump.  That was the final straw.

Every now and then I look at my 8 ft long DPF sitting in my garage and think that maybe I should return my truck back to stock... 

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21 minutes ago, Murphy8166 said:

I deleted my 15' PSD about two years ago.  Did it myself for about $900 in parts (race pipe, No Limit EGR delete and SCT Tyrant tunes) and it was the best thing I ever did for the truck.  Yeah, I will admit that the unfiltered diesel smell is unpleasant but I don't smell it in the cab nor do I stand outside my truck when running.  I got really tired of the issues and "limp mode/ shut down" messages for no apparent reason other than the dealer having to complete a manual Re-Gen.  When I did have a repair item come up I was looking at $1,000 bucks to replace the DEF reductant pump.  That was the final straw.

Every now and then I look at my 8 ft long DPF sitting in my garage and think that maybe I should return my truck back to stock... 

This is the primary reason I purchased an Edge Insight CTS3 monitor for my duramax.  Read horror stories of limp mode due to untimely or unknown regen cycles (my truck gave no messages on dash for regeneration cycle)  I can view my soot levels and push a manual or mobile regen on the fly.  My truck goes into regen when it hits 42g.  Now, anytime I'm over 30g and know I'll be driving for 30+ miles, I just force the mobile regen. I can also see my DEF levels whereas my GMC just said "Diesel Exhaust Fluid OK" until it gets below 40%.  

It's amazing how advanced trucks have become and all these fancy screens and information centers  throughout the cab and I can't get a simple regen message, an accurate DEF level  above 50% or even if my truck is in 4wd (this one drives me nuts coming from Ford trucks).  I guess it's helped companies like Edge though.

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1 hour ago, wedge88 said:

This is the primary reason I purchased an Edge Insight CTS3 monitor for my duramax.  Read horror stories of limp mode due to untimely or unknown regen cycles (my truck gave no messages on dash for regeneration cycle)  I can view my soot levels and push a manual or mobile regen on the fly.  My truck goes into regen when it hits 42g.  Now, anytime I'm over 30g and know I'll be driving for 30+ miles, I just force the mobile regen. I can also see my DEF levels whereas my GMC just said "Diesel Exhaust Fluid OK" until it gets below 40%.  

It's amazing how advanced trucks have become and all these fancy screens and information centers  throughout the cab and I can't get a simple regen message, an accurate DEF level  above 50% or even if my truck is in 4wd (this one drives me nuts coming from Ford trucks).  I guess it's helped companies like Edge though.

The CTS3 can force a regen? Now I have to go look at the difference between the CTS2 and CTS3 (and confirm that I have the CTS2). I didn't see soot levels in the CTS2, but I'll admit it's been a few years since I looked at the manual and setup. Any quick tips on how/where to set up soot level? I monitor regen on/off, EGT, and trans temp. I filled an open spot with trans gear and torque converter status, but soot level would be more useful.

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14 hours ago, mikeo said:

The CTS3 can force a regen? Now I have to go look at the difference between the CTS2 and CTS3 (and confirm that I have the CTS2). I didn't see soot levels in the CTS2, but I'll admit it's been a few years since I looked at the manual and setup. Any quick tips on how/where to set up soot level? I monitor regen on/off, EGT, and trans temp. I filled an open spot with trans gear and torque converter status, but soot level would be more useful.

Yep, the CTS3 can force a manual (sitting still) or mobile (driving) regen from the diagnostics menu.  Didn't realize until after 6 months of use but played around with it on a long trip while in the passenger seat.  Not sure on the CTS2 but could be as simple as a software update.

On the CTS3 the soot is listed under "soot" in the standard PIDs menu and DEF is under UREA.  I watch UREA level, soot, EGTs, turbo boost PSI, trans temp, battery voltage, gear and corrected speed because I put a size larger tires on the truck.  Under the advanced PID menu I have REGEN_AVGD which is distance between regens. 

 

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I went and checked my CTS2 and I do have the manual regen and soot levels. Now I'm going to have to look for the REGEN_AVGD and figure out where to put it. My truck isn't my daily driver (and it was just rebuilt after a wreck; $25k of damage from a fender bender while towing a trailer), I typically only drive my truck when I'm towing the boat, travel trailer, etc. or there is big stuff to get at the hardware store.

On a different note, I just put H7 AGM batteries in to replace the 5 year old H6 flooded batteries. Swapping the batteries, even H6 is a PITA. I figured if I was going to do it I would take the time to get the H7 in, put the heater blanket on them, and connect the wifi maintenance charger. It pains me to say that I got the Champion H7 AGMs for a steal of a deal at Pep Boys. (but maybe it's good since I'm fairly sure they lost money price matching)

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