GM Truck Club
THE PREMIER CHEVY TRUCK & SUV FORUM
Founded in 2004 ~ We're the #1 Chevy Truck & SUV Forum.
Silverado & Sierra | Tahoe & Yukon | Suburban & Yukon XL | SUV & CROSSOVER

'08 Silverado, smoke upon start up

Discussion in 'Chevy Silverado Forum (GMC Sierra)' started by BlackBowtie, Mar 4, 2013.

  1. BlackBowtie

    BlackBowtie New Member

    Joined:
    Mar 1, 2013
    Messages:
    11
    Likes Received:
    0
    Hey guys,
    I noticed today that upon start up, I saw 3-4 seconds of white smoke.
    What could cause this?
    #1
  2. RayVoy

    RayVoy Active Member

    Joined:
    Apr 18, 2012
    Messages:
    2,122
    Likes Received:
    5
    If it was a cold morning, it's just condensation.
    #2
  3. j cat

    j cat Active Member

    Joined:
    Sep 28, 2010
    Messages:
    1,522
    Likes Received:
    3
    on a cold start you will see water vapor , and even see water draining out the mufflers. if the engine is hot and you see white vapor that would be coolant. also it will have a smell to it.
    #3
  4. Kuntryboy

    Kuntryboy New Member

    Joined:
    Jan 20, 2011
    Messages:
    30
    Likes Received:
    0
    if the smoke was blueish then its probably a leak of some sort.
    #4
  5. BlackBowtie

    BlackBowtie New Member

    Joined:
    Mar 1, 2013
    Messages:
    11
    Likes Received:
    0
    Kuntryboy,
    It did have a blueish hue. It was definitely something being burned off.
    where would the leak be coming from?
    #5
  6. RayVoy

    RayVoy Active Member

    Joined:
    Apr 18, 2012
    Messages:
    2,122
    Likes Received:
    5
    If the engine is cold, there is no exhaust heat to burn off any fluid.
    If the engine is hot, it is probably engine oil.
    #6
  7. BlackBowtie

    BlackBowtie New Member

    Joined:
    Mar 1, 2013
    Messages:
    11
    Likes Received:
    0
    Ok, so let me put this all together.
    I know it's engine oil because I'm always down 2 quarts within a span of 5,000km.
    Yes, this issue is happening at cold starts. This morning I stood behind it, used the remote start and thick, white, blueish smoke came out for 2-3 seconds, then exhaust vapours.
    #7
  8. j cat

    j cat Active Member

    Joined:
    Sep 28, 2010
    Messages:
    1,522
    Likes Received:
    3
    the blue smoke on first starting was 100% on the chev/GM 305CU engines. the valve guides GM did not properly machine to prevent this. with a 2008 engine my guess would be a valve issue, possible seals.

    if you have the AFM this may be serious . can also be the valve cover internal PCV system. may have had this fail with the use of non GM approved engine oils. sludge forms causing the crankcase venting system to not work correctly.

    oil usage with the crankcase venting system failure is what happens.
    Last edited: Mar 7, 2013
    #8
  9. geo1

    geo1 New Member

    Joined:
    Mar 6, 2013
    Messages:
    113
    Likes Received:
    0
    I agree with j cat,one question for you is ,do you idle alot.amotor at idle is at high vacuum,pulling oil past valve seals.try shutting down quicker on end of commute to see if smoke lessons

    - - - Updated - - -

    add to; this is not operator error,simply a diagnostic aid in youre oil consumption
    #9
  10. Enkeiavalanche

    Enkeiavalanche Moderator

    Joined:
    Apr 5, 2010
    Messages:
    5,365
    Likes Received:
    14
    Sounds Very familiar :grrrrrr: Do you have AMF? Have you seen blue smike out the back when driving at highway speeds? How many miles do you have?
    #10
  11. geo1

    geo1 New Member

    Joined:
    Mar 6, 2013
    Messages:
    113
    Likes Received:
    0
    lost me ,what is amf,learing as i go on here ,thanks
    #11
  12. Enkeiavalanche

    Enkeiavalanche Moderator

    Joined:
    Apr 5, 2010
    Messages:
    5,365
    Likes Received:
    14
    When it goes from 8 to 4 Cyl and back.. There is a TSB on this I just had the work done to my 08 5.3.
    #12
  13. j cat

    j cat Active Member

    Joined:
    Sep 28, 2010
    Messages:
    1,522
    Likes Received:
    3
    AFM this is active fuel management. the engine PCM determines when you need more power then it has all 8 cylinders working when at idle coasting you drop out cylinders to conserve fuel. this type engine has issues with oil .

    I have read GM plans to dump these engines. new engines 2014. direct injection with variable valve timing . this is a good design to get max power and MPG. The question is can GM do it successfully??????
    #13
  14. Enkeiavalanche

    Enkeiavalanche Moderator

    Joined:
    Apr 5, 2010
    Messages:
    5,365
    Likes Received:
    14
    Who wants to be a TEST Rat for GM?
    #14
  15. RayVoy

    RayVoy Active Member

    Joined:
    Apr 18, 2012
    Messages:
    2,122
    Likes Received:
    5
    WE DO, WE DO; and everyone with a 5.3 AFM waves their hands
    #15
  16. Enkeiavalanche

    Enkeiavalanche Moderator

    Joined:
    Apr 5, 2010
    Messages:
    5,365
    Likes Received:
    14
    I'm still in it..
    #16
  17. RayVoy

    RayVoy Active Member

    Joined:
    Apr 18, 2012
    Messages:
    2,122
    Likes Received:
    5
    This conversation is reminding me, that I should check my oil level in the morning.
    #17
  18. BlackBowtie

    BlackBowtie New Member

    Joined:
    Mar 1, 2013
    Messages:
    11
    Likes Received:
    0
    Ah yes, I do have the AMF motor.. so im guessing that explains alot.
    I warm the vehicle up on cold mornings.. is this hurting it?
    So I guess I have to live with this?
    #18
  19. Enkeiavalanche

    Enkeiavalanche Moderator

    Joined:
    Apr 5, 2010
    Messages:
    5,365
    Likes Received:
    14
    Go to dealer and talk to the Service guy..
    #19
  20. Old Iron nut

    Old Iron nut New Member

    Joined:
    Mar 6, 2013
    Messages:
    5
    Likes Received:
    0
    I'm not familiar with this engine but due to mileage, age, or other gremlins you could have a problem with valve seals. I have an older GMC truck that currently has this problem. Cheers, Old Iron nut.
    #20

Share This Page