2011 Duramax DEF Fluid Issue / Problems

[RI Chevy Silveradoman]

SCR

Please forgive me, but what is SCR? :???:

 

[blizzardplowman]

-15 Last week, Truck sat outside. So far no problems

 

[btfarm]

SCR= Selective Catalytic Reduction or as they say... magic through chemistry.:hihi:

 

[RI Chevy Silveradoman]

TY! I am not privy to all these acronyms.

 

[Ed HD]

I had to google it, LOL.

 

[tammlyn]

def

in the 2500 and 3500 pick ups there is no def but in there 2500,3500.4500 cab and chassis they use def in 2011. i was worried about def thats why i purchased a used truck with the lbz hold the def i havent seen, a new one yet but where i am the average temp in the last fiew weeks has been minus 40 celcius nobody will convince me that the def wont be a problem,on the good side i just crossed the dreaded 160,000km,waranty finished and no parts fell off,so far so good,hopefully the gm engineers wont see this post and activate the self destruct code for my truck.

 

[Ed HD]

At a Farm Bureau conference up in Duluth MN and the man I sat next to at lunch was complaining about issues he was having with his truck, said it went into limp mode and locked him to 55 MPH since the tank thought it was empty, even though it was full. Said his dealer hasn't been able to do much yet. I hope GM gets it shit together, otherwise all the torque in the world won't solve issues with frozen DEF.

 

[durallymax]

Gm seems to be having a lot of issues with their SCR system, seems they forgot a lot of things.

I havent talked to many people with SCR systems who arent having a few issues. On our new AGCO with SCR, AGCO had a recall on the original DEF Sending unit/heater/quality tester ($1500 piece) so all of them had to be replaced. Then Ours went bad anyways so i swapped to "recalled" one in and it ran fine, then later on installed a new proper one. And just a couple days ago I had the DEF dosing module go bad, dont even wanna know what it costs. but its running now.

Our tractor simply detects that the DEF is frozen, then goes into thaw mode where it raises the RPMs to 1200 until the DEF is thawed. It gives full power for 30 minutes and after 30 minutes if there is still no flow of DEF it will de-rate the power by 60% because after 30 minutes if its not flowing either hell froze over, its empty, or somethins not working right.

I have to give them credit, except for some failed parts, their system works flawless, but thats what happens when you release it 2 years ahead of time to the public, all of the bugs get worked out and now all of the other MFGs are struggling with issues.

 

[Jensbiker]

There are a lot of flaws with the def system in the siverado. The main issue is the def fluid freezing on the sensor. Once this happens the sensor cannot read the fluid level. The fluid in the tank tends to slush rather than totally freeze. The heater in the tank is not able to do it's job to thaw the def in the allotted time. You will receive a def low warning at 1000 miles and another around 500 and then again at 300. After this if the tank has not been thawed and made sure that it is full the truck will be put into limp mode. Once this has happened you will have to go to the dealer and have the tank flushed and new flash program installed. I have had this happen twice to my truck in less than 30 days. Dealer cannot actually release the code. Once they have done what they can they may send you away in limp mode because truck has to be driven for a while before it will reset. This has been very frustrating and needs to be addressed in a big way by GM. The most powerful truck on the road and it's locked out at 55. Love the truck, but this is reply embarrassing to GM

 

[dmaxx3500]

gm should run a eng coolant line thru the DEF tank 200deg coolant would thaw out the fluid every time you drove the truck

 

[durallymax]

gm should run a eng coolant line thru the DEF tank 200deg coolant would thaw out the fluid every time you drove the truck

Its not that simple.

Our new tractor uses engine coolant to thaw the DEF, when it senses the DEF is frozen it speeds up the idle to get the engine warmed up quicker and thaw the DEF, but once its thawed it stops.

Why does it stop? Remember that DEF is Nitrogen, and Nitrogen is a tricky chemical. If you heat the DEF too much the quality will depleat and you will be back to square one of limp mode and draining the tank.

Dmax is not the most powerful, missed that by 3hp, but the Dmax is underrated .

Cummins gets by , by using their credits. Their larger engines meet emissions very well so the EPA allows a "flex" for their 6.7