does DEF freeze on you?!?

Discussion in '2011 LML Duramax' started by great white, Dec 4, 2011.

  1. great white

    great white Active Member

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    First off, I don't have a new DMax.

    But I have been reading a bit here and there.

    I've read a couple places that def freezes between -9 and -11 C.

    WTF?

    Does it freeze up on you in the tank and lines in cold weather?

    This can't be true, otherwise no one north of Florida would be able to run one....there must be a heater or something.....

    Even if there is a heater, wouldn't it be frozen up when you leave it overnight?

    Very curious on how GM dealt with this....
     
  2. THEFERMANATOR

    THEFERMANATOR FRANKENBURBAN Staff Member

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    Yes it freezes, and yes they have a heater. Problem is though when the DEF freezes the engine will run in reduced power mode of about 40-50% power until the def comes back up to a liquid state.
     
  3. bigdisneydaddy

    bigdisneydaddy Recruit

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    I think they already had a service bulletin about it in very cold climates. Places like Alaska and Canada had cold enough weather that the stock heater was insufficient.
     
  4. great white

    great white Active Member

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    Well, I can cross any DEF equipped truck off my future "must buy" list.

    What the heck were they thinking?

    You need it to run as per normal but it can freeze overnight.....I mean, really.

    What were they thinking?
     
  5. BoostN

    BoostN Administrator Staff Member

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    They are putting insulated tanks in the Severe northern climates for the freezing issue. Since the latest reflash update, not many problems are being reported with the DEF now.
     
  6. great white

    great white Active Member

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    But, what happens if your truck sits for a couple days in -15 C temps?

    Not an unusual circumstance around these parts.

    Or even just overnight?

    Frozen DEF?

    Dead battery so no start?

    Plugging in a heater is not an option at an airport parking lot and such.

    Sounds like a PITA all the way around to me....
     
  7. BoostN

    BoostN Administrator Staff Member

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    The heater doesn't run unless the truck is running. I'm not sure how GM designed it, but.. I'm betting they have a waiting period programmed for the DEF while the tank is frozen.. Could you imagine the pissed off people that starts their truck every morning and you have to wait for your tank to unfreeze, that's not logical, and GM's phones would be ringing off the hook and the forums blowing up.

    I'm not saying it's the greatest thing either, but mine hasn't give me one problem (DEF related). Granted my parts aren't as cold as most.
     
  8. LtEng5

    LtEng5 Member

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    there is a heater hose line type set up for the DEF tanks. as the engine warms up and you get heat in the cab; the DEF tank also is heated. As I understand it there is no reduced power with a frozen DEF system. I could be wrong here thou.
     
  9. JiFaire

    JiFaire Lieutenant Staff Member

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    This is a GREAT question, guys... one of those things that some engineer (in a warm climate) just wouldn't think of...

    ... and one that every guy in Alberta or Alaska can't ignore!
     
  10. btfarm

    btfarm Quarter Million Worth Staff Member

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    It seems to me that since all kinds of DEF equipped vehicles have been running for years in Europe that there wouldn't be all that much for them to have figured out. A bunch of operational data should already be available. Add in that all the major OEMs do at least a couple of years of testing in extreme climates for most every all new system. Should be a slam dunk. Or at least only minor issues.
     
  11. BoostN

    BoostN Administrator Staff Member

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    I know it gets cold in Detroit.. that is the heart of these trucks ya know... Freezing is freezing.
     
  12. ryanryan

    ryanryan New Member

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    WOW.........do you honestly think GM would release a truck with that much bullshit going on??? Other than the one DEF problem I had(which wasn't related to cold weather), first year truck....NBD, I haven't even noticed that there is a SCR system on it. I've never had any problems, and my truck has sat outside for a week or more at -20*C. There is no reduced power mode or any other stuff like that, you just start it up and go....it'll thaw itself. I've never plugged my truck in, BTW.

    AND.....many class 8 trucks have been running SCR systems for years and years. It's nothing new...... This type of post comes up every winter!!
     
  13. 3500GMC

    3500GMC Stand Your Ground

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    Bottom line: The EPA is slicing our throats.

    They legislate the impractical with lofty goals and zero tolerance effective- NOW.

    Meanwhile china spews forth filth into the sky, everyday, far exceeding the U.S. now, and in it's manufacturing height/hay-day way back.
     
  14. JiFaire

    JiFaire Lieutenant Staff Member

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    Ok, so we have 3 votes for 'it's gonna be fine', which is usually my line, since I'm the big SCR supporter, but I'm still curious; what happens to your power once the stuff freezes?

    Class 8 rigs don't have an automatic 'power-reducer' on them when your DEF system is not working (frozen or otherwise) like the new trucks.

    Before anybody gets uptight about the sky falling or not, re-read post #2.

    If DEF freezes (which it should, chemically), I will assume that the engineers have taken care of any expansion issues (which are a water-based phenomenon), but if the engine will really run in reduced-power mode until the DEF thaws out, I would honestly like to know that.

    I know Ontario and Detroit get chilly, but we really do see -40 several times a year, and it would be nice to know if you can add an antigel to the stuff?
     
  15. great white

    great white Active Member

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    From Gm techlink:

    There ya go. Decide for yourselves if it is a problem or not.
     
  16. Dad's 05 LLY

    Dad's 05 LLY Real Trucks Don't have Spark Plugs!

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    I was at a Farm Bureau conference last January in Duluth MN, and at lunch one of the days the guy was on and off the phone with the local dealer, as his DEF was frozen and the truck was in limp-home mode, not allowing him to go over 50 MPH (pretty much all 4-lane freeway for 400 miles for him home too) and the dealer couldn't do anything, since the truck was so new, they had no idea. It may have broken something too, but he was pretty much SOL and had to drive home at 50 from what I heard...
     
  17. 3500GMC

    3500GMC Stand Your Ground

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    ^^ The guy was probably thinking "I can't drive my 50 thousand dollar f'n truck because my f'n piss tank is frozen" ^^
     
  18. BoostN

    BoostN Administrator Staff Member

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    I don't know what you would break. The computer limits the power because it isn't sending fluid through the lines. That's why it's limited...

    The DEF system is without a doubt something else to cause trouble and break.. But, we better get use to these things as I don't see it ever becoming any better (emissions wise) until something else comes out to replace this DEF.
     
  19. Dad's 05 LLY

    Dad's 05 LLY Real Trucks Don't have Spark Plugs!

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    I'll just buy up a fleet of 05-07's. IMHO they look better and no emissions crap. :D
     
  20. ryanryan

    ryanryan New Member

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    Re-read post #12....

    There is no mode that it goes in to, once the tank is frozen. It assumes a level, and let's you go and warm up. It could go into limp mode, but part of the recall addressed that. In some cases(not many), their truck would go into limp mode and say low DEF or DEF quality low if the DEF froze. That is now fixed, the heating cycle is improved, and they added a shield and insulation for Canadian residents.
     

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