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84 chevy truck

Discussion in 'Chevy Trucks' started by ricojeff, May 3, 2005.

  1. ricojeff

    ricojeff Junior Member
    from 37914
    Messages: 2

    When I idle blue smoke comes out exhaust pipe what could this be ?
     
  2. QMVA

    QMVA Senior Member
    Messages: 431

    Wrong forum

    As for your problem I think its from the engine burning oil. You may want to check oil level and color.
     
  3. William B.

    William B. Senior Member
    from S.E. IA
    Messages: 978

    Your problem is that the valve guide seals are bad on the heads. This is very common on the old 350 and other engines.About the only way to fix the problem is to have new seals installed.

    William
     
  4. ricojeff

    ricojeff Junior Member
    from 37914
    Messages: 2

    thanks

    I really appreciate the help

    Jeff
     
  5. PremierLand

    PremierLand PlowSite.com Addict
    from detroit
    Messages: 1,572

    im just a little curious about smoke... I know like black some means one thing, blue means another, and white another, etc.... but what do they mean? lol

    I thought blue meant trans and black meant engine. I guess im wrong, but again, what problem does each color represent? thanks

    Cause when I blew my first tranny out there was a CRAZYYY amount of smoke... but when I blew my second tranny out, there was nothing but a clunk.
     
  6. Mick

    Mick PlowSite.com Veteran
    from Maine
    Messages: 5,546

    I'm from way back (like the 60s), but I always took exhaust smoke as:

    Black - burning oil
    Blue - unburned gasoline (idle set too rich or timing off)
    White - water vapor (perhaps from a cracked head if it continued after warmup)
     
  7. PremierLand

    PremierLand PlowSite.com Addict
    from detroit
    Messages: 1,572

    yaaa, thats what I was thinking. My pappy told me that, I just forgot... dohhh
     
  8. lawnandplow42

    lawnandplow42 Senior Member
    Messages: 110

    why would transmission smoke come out the exhaust pipe?
     
  9. William B.

    William B. Senior Member
    from S.E. IA
    Messages: 978


    Shouldn't the blue and black be switched around. That's what I was always told. Blue was the oil getting burned off and black was fuel, because it was too rich.

    William
     
  10. Mick

    Mick PlowSite.com Veteran
    from Maine
    Messages: 5,546

    It could be. It's been a long time since I last thought about it, really. I haven't done much mechanical work beyond replacing plugs, wires and an occasional water pump since the late 70s. About ten years ago I went into a NAPA store asking for points and condensor for an alternator. The guy looked at me like I was stupid and said nobody did that anymore; they changed the whole alternator for around $100. He finally did find the points and condensor I needed, though.
     
  11. PremierLand

    PremierLand PlowSite.com Addict
    from detroit
    Messages: 1,572

    no idea, but when my trans went out I saw tons of smoke out the rear end. maybe the trans just blew up and the smoke drifted towards the rear. IDK but im glad I sold the truck
     
  12. derekbroerse

    derekbroerse 2000 Club Member
    Messages: 2,377

    Black Smoke (gasser engine): Rich condition, your plugs will likely be black too.

    Blue Smoke: Oil burning condition, worn engine components.

    White smoke (not to be confused with start up condensation steam!): Coolant leak,internal, like head gasket etc.

    A tranny failure that causes lots of smoke is likely one that blew up literally and spewed its oil all over the hot exhaust. The 'clank method' of tranny failure is internal.

    The blue smoke on this '84 is either valve guides or valve guide seals. If it is mainly on startup (ie clears up after a min or so), it is more likely the seals. If it is all the time at idle, the guides may be worn and seals may or may not do the trick (depending on how bad they are). If it smokes all the time, well, probably the engine is just tired.

    Remember if the truck has a catylitic convertor on it, it may be smoking a lot more than you think, as what you are seeing is just the 'overflow' that the cat can't handle...

    PS: Seals can be done on the engine with compressed air fittings etc. Valve guides require machining, ie: pulling the heads. And naturally, a tired engine, well, needs pulling entirely.

    If you are lucky, its just seals. Good Luck!
     
  13. joe_padavano

    joe_padavano Member
    Messages: 68

    Two things to add to derek's post. First, if the truck is cat-equipped and has been burning oil, it's possible that the cat has been contaminated and will need to be replaced. Second, it IS possible for trans oil to get sucked into the engine if you have a TH350 or TH400 with a vacuum modulator. If the modulator diaphragm fails trans fluid will be sucked into the engine through the modulator vacuum pipe that goes to the intake. This will also show up as bluish-white smoke, however this failure will also cause the trans to only upshift under wide open throttle, so you'll know there's failure pretty quickly (unless you drive like me and ALL your upshifts are at WOT :blush2: )
     
  14. derekbroerse

    derekbroerse 2000 Club Member
    Messages: 2,377

    Joe is absolutely correct on both points. :nod: