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White/Black Smoke

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by Hayduke, Aug 8, 2000.

  1. Hayduke

    Hayduke 1/2 ton status

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    here's what's happening, it seems like i'm burning oil, when i hit the gas from a stop a white cloud puffs out of the pipes, kind of big too. sometimes i seem to "burn" more than other times, if i'm sitting in stop and go traffic it smokes the most. it doesn't smoke much when i'm just sitting, just when i touch the gas. and if i put it to the floor a black cloud puffs out. also on a recent trip to west virginia i noticed thin black smoke coming out of my pipes whenever the truck was straining to keep speed on a really steep long climb....
    BUT when i check my oil VERY little is being lost, maybe under two quarts between oil changes.
    any input? it's a stock 1986 305, just under 100k on it....
    thanks.
    HAYDUKE

    Insured By COLT.

    http://haydukesk5.coloradok5.com
     
  2. ken

    ken 1/2 ton status

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    Sounds like your rings are shot. This would produce black smoke cause of unburned fuel, and white smoke due to oil escaping past the rings and up into the combustion chamber. It's only a matter of time before "Johnny-Law" pulls you over for a fix-it ticket due to excessive smoke. Time to rebuild!

    ken
     
  3. Emmettology 101

    Emmettology 101 3/4 ton status

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    This is what I have always been told and my experiences:

    White Smoke = Water/coolant
    Black Smoke = Fuel
    Blue Smoke = Oil

    You may have a tiny coolant leak into you cylinders somewhere, headgasket?

    Mike [​IMG]
    1982 GMC Jimmy - <font color=green>Emmett</font color=green>
    http://emmett.coloradok5.com
     
  4. Boss

    Boss 1/2 ton status Author

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    Maybe your carb needs a tune up. It could be running rich. The fuel/air mixture maybe off a bit. That's a thought.
    Boss
     
  5. ken

    ken 1/2 ton status

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    Good call, Emmett. Does your engine have an aluminum factory intake? If so (or even if not) the intake gaskets may be leaking coolant into the intake tract, which would cause the white smoke. If this is true, then it's only a matter of replacing the intake gaskets. As for the black smoke, maybe, like others say, your carb is out of tune.

    ken
     
  6. Scoobydoo

    Scoobydoo 1/2 ton status

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    Yep, what they said! about the smoke colors is right.(white=water, black=gas, blue=oil)
    Also are you losing coolant?(it doesn't have to be much) does your tailpipe smell sweet like antifreeze?(assuming you do use antifreeze) If so you need a head gasket, which one is your guess?
    The "black" is your air/fuel mixture and it is not uncommon for it to run rich when going up a mountain! think about it you are changing elevation so air is getting thinner and you are heavy on the gas. you may just need an adjustment or a rebuild on your carb.
     
  7. Can Can

    Can Can Pusher Man Staff Member Super Moderator

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    Check the underside of your oil-fill cap for sludge that looks like curdled chocolate milk- this indicates coolant in the oil.
     
  8. Hayduke

    Hayduke 1/2 ton status

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    Ok guys, here's what i've found....
    a small internal coolant loss, wouln't have noticed it if i wasn't keeping an eye on it. changed my oil today and pulled a couple of plugs out to take a look at 'em and they are fine, no oily build up. i also drained the oil into a clear jug and so far there has been no water seperating out of it. i'm watching the "cloud" that puffs out more closely too and it is a nice white color. i'm leaning away from my rings and more toward my intake gasket? anymore input?
    thanks!
    HAYDUKE

    Insured By COLT.

    http://haydukesk5.coloradok5.com
     
  9. 84k5

    84k5 1/2 ton status

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    Sometimes I see a puff of white smoke when I start my k5 in the morning. Is this bad?

    Brian
    84k5, 4"Skyjacker lift,33x12.5 Goodyear MTR, 15x10 Bajas
     
  10. dawson444

    dawson444 1/2 ton status

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    Hey my rig did that, I got some of this stuff called STP Smoke treatment at advanced autoparts and poured the bottle in the oil thing and boom problem fixed next time i cranked it up.

    Dawson
    88 K5 167k miles
     
  11. jim82

    jim82 Registered Member

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    84 that white smoke on start up, make sure it isn't blue. if its blue its probably just the valve guide seals letting a little oil thru, had this hapen in a couple a cars, new ones are cheap and not too hard to do.
     
  12. 90K5

    90K5 1/2 ton status

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    Mine has some white smoke on startup occasionally and i think its pretty common on 350s.

    90K5
     
  13. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

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    Usually a little white smoke on start up is normal. Its just a little condensation. What is common on <font color=red> 350's </font color=red> is the little puff of blue on start up. I personally have never seen the intake gasket being the culprit for white smoke, if it was the intake gasket it would run pretty crappy. When it is cold take the rad cap off and start it up, wait for it to settle down and start looking for bubbles, if the head gasket is gone quite often you get exhaust in the coolant and coolant into the cylinder. My friends 4.3 had a blown head gasket and we did a leak down test and almost had a geyser blowing out thru the rad cap. It was also blowing white smoke.
    Just my 2 cents


    Rene 81 Jimmy,350,SM465/NP205,FF14 bolt,HD Dana 44,3.73's,4"susp.,35"Grabber MT's,body in progress
     
  14. Mr Red

    Mr Red 1/2 ton status

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    Intake or Head gasket. Maybe try checking tourgue on intake bolts (in proper order) and / or replacing intake gasket first & pray it ain't the Head gasket or cracked head.

    Good Luck,
    <font color=red>David, '86 K5</font color=red>
     
  15. 89Jimmy

    89Jimmy 1/2 ton status

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    My '85 had some pretty significant white smoke(steam) out the exhaust after warm-up. A packet of bars-leaks brown pills in the radiator cured the symptom till I can open 'er up. Local GM Tech told me bars-leaks was recommended in the GM manual as part of intake work, and also used on alum. head motors. Who am I to argue?
    John

    So Much to do, So LITTLE cash.
     

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