LBZ: Blue smoke [Archive] - Duramax Diesels Forum

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Huntinducks82
01-03-2009, 07:15 PM
When i start my truck in the mornin so that it can warm up it smokes blue smoke pretty bad while idle and high rpm idle. But when i start to drive it it goes away. After doing some readin i have found that this is pretty commin in the lbz and most Dmax motors. My question is has anybody found anything that will clear it up. I use lucas fuel treatment cause of the cold temps.

Turbo Buick 6
01-03-2009, 07:18 PM
I have never seen blue smoke from my truck. When its cold it smokes white pretty bad but thats because I have no intake air heater. Blue smoke usually means oil. What does the smoke smell like?

racinmike77
01-03-2009, 07:19 PM
I have had 2 trucks that did the same thing. I think its normal, probably not good, but just unburnt fuel.

Usually smells like raw fuel

Huntinducks82
01-03-2009, 07:48 PM
It does not smell like oil smoke but it is blue. Also i have to truck set so that it sounds like an lb7 while idle (just remembered that). I wonder if that has something to do with it. But it also does it at high idle so i would not think so. Its not been usein any oil, i have been checkin it since i noticed it.

juddski88
01-03-2009, 10:33 PM
mine does it and i am pretty certain it is a valve seal...but i havent had the time and place to tear into it yet

Turbo Buick 6
01-03-2009, 10:40 PM
It does not smell like oil smoke but it is blue. Also i have to truck set so that it sounds like an lb7 while idle (just remembered that). I wonder if that has something to do with it. But it also does it at high idle so i would not think so. Its not been usein any oil, i have been checkin it since i noticed it.

mine does it and i am pretty certain it is a valve seal...but i havent had the time and place to tear into it yet


More likely. It doesn't take much oil to turn the smoke blue

juddski88
01-03-2009, 10:49 PM
the only thing throwing me off is the clatter i hear when it's cold too, it sounds like a hard part or loose clearances somewhere...but who knows, i will see if the new seals fix the sound too

Huntinducks82
01-04-2009, 12:45 PM
I have no clatter just smoke.

paint94979
01-04-2009, 12:51 PM
I have no clatter just smoke.

honestly i wouldnt worry about it

Whitetail Addict
01-04-2009, 01:34 PM
Mine smokes white but only a slite bit on the cold days, and for only a few seconds. It varies based on the amount of humidity in the air also, more noticable on snowy days. Above 40* or so it does nothing.
I believe it is due to the block and intake air being cold and there is not enough heat built up in the cylinders to completely burn up the fuel. When it is plugged in there is no white smoke, even at 15-20*.
Seems like most any diesel will do it in cold temps.

coldLBZ
01-04-2009, 09:27 PM
I usually get a bit of blue smoke while warming it up around 32 F when the high idle doesn't come on.

mytmousemalibu
01-04-2009, 09:52 PM
Yupper, mostly "cold diesel symdrome" with maybe a touch of oil turning it blue. With a cold motor things arn't sealing up as they should, in your case, id say perfectly normal unless it starts belching smoke or keeps smoking when warm. Mine white smokes when cold and even warm although not visible warm unless there is backlighting but none the less, my case its the big injectors. Causing somewhat of an incomplete burn at idle.