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Blowing smoke on startup only?

Discussion in 'Truck & Equipment Repair' started by kbsnow, May 6, 2010.

  1. kbsnow

    kbsnow Senior Member
    from Chicago
    Messages: 146

    OK, heres the issue. I just changed intake manifold gaskets on my 91 5.7 tbi and no leaks, BUT, I am now blowing a puff of smoke on startup after it sits for a while. Now, I always used Mobil Clean 5000 and NEVER blew smoke. After the gasket job, I bought 5 qts of Oreilly's 5-30 for $1.99 each to run through and clean any gunk from the engine.

    Could it be the cheap oil? Do you think this will go away if I switch back to my regular oil? The truck has 172,000 miles and runs like a clock.
     
  2. 2COR517

    2COR517 PlowSite Fanatic
    Messages: 7,115

    Sounds like valve seals
     
  3. streetsurfin'

    streetsurfin' Senior Member
    Messages: 770

    Are you sure you didn't drop any old gasket material or other debris that may have plugged an oil drain gally at the back of the heads? Old valve seals on high mileage engines can degrade and chunk apart, leaving pieces partially plugging the drains. Oil builds up on top of the head. Whether drains are restricted or not it could still be bad seals.
     
  4. theplowmeister

    theplowmeister 2000 Club Member
    from MA
    Messages: 2,552

    Ditto

    OK message to short to post
     
  5. kbsnow

    kbsnow Senior Member
    from Chicago
    Messages: 146

    Yea I figured its probably the valve seals. I kept everything clean, and used my shop vac to catch any gasket material when I was scraping. I plugged all the head openings real well, and never had the valve covers off...didn't need to. $10 for Felpro seal kit, plus whatever valve cover gaskets cost. Oh well, got all summer to do it.
     
  6. theplowmeister

    theplowmeister 2000 Club Member
    from MA
    Messages: 2,552

    What color is the smoke?
     
  7. 2COR517

    2COR517 PlowSite Fanatic
    Messages: 7,115

    Oooooh. Good question :nod:
     
  8. kbsnow

    kbsnow Senior Member
    from Chicago
    Messages: 146

    Blue..its oil..and you can smell the oil...
     
  9. kbsnow

    kbsnow Senior Member
    from Chicago
    Messages: 146

    The HECK with changing the seals. I'm just gonna put some high mileage oil in it, 10w-30, and hope for the best. Its a plow truck only, gets very little summer use, and its not worth the hassle.
     
  10. cubicinches

    cubicinches PlowSite.com Addict
    Messages: 1,412

    You took the words right out of my mouth... :)
     
  11. MickiRig1

    MickiRig1 PlowSite Veteran
    Messages: 3,617

    An Engine with that many miles will puff a little smoke on startup. I would not worry about it unless it leaves a trail of smoke behind it all the time. My 89 puff's oil smoke at startup, it still passes Emissions Checks every time.
     
  12. KSikkema

    KSikkema Senior Member
    Messages: 179

    Not too much to worry about as they almost all do it. IF you do the repair though, just remember that you must pressurize the cylinder with air in order to prevent the valve from falling into the cylinder when you remove the valve keepers and spring! Not too sure how much experience you have with this, but it is something some people may overlook
     
  13. kbsnow

    kbsnow Senior Member
    from Chicago
    Messages: 146

    Thanks for all the responses. I'm not even gonna worry about it. It is MUCH better with the Castrol High Mileage 10w-30. I'm thinking its been blowing smoke a while, but was not noticable until I put some CHEAP oil in. Since it is a plow truck, and doesn't smoke while driviing, and is still a solid and a strong runner, I'm gonne leave it be.

    I have rebuilt many an engine, and don't think its worth the hassle to do the seals, etc...
     
  14. MickiRig1

    MickiRig1 PlowSite Veteran
    Messages: 3,617

    might even think about stepping up to a 40 weight oil. I have had good luck with a heavier weight oil with oil useage.My Daughter's Toyota would go through a QT a week of 30 weight. I went to 40 weight and it's gone 2 weeks without a quart used. My Automotive repair course instructor always told us to go up a grade on oil changes. This cures oil useage he said.
     
  15. kbsnow

    kbsnow Senior Member
    from Chicago
    Messages: 146

    ,,now when you say up a wait to 40w, do you mean 10w-40, or straight weight? For the summer I was thinking of straight weight for the little driving it will do, and go back to the 10w-30 for winter.
     
  16. rsails

    rsails Junior Member
    Messages: 24

    Advice needed - Replacing Vavle seals 84 RC

    All

    First time replacing valve seals.


    I order intake and exhaust seals
    2 - new valve covers

    borrowing adapter for compressor and valve compression tool.

    Any words of advice before I tackle this project?
     
  17. kbsnow

    kbsnow Senior Member
    from Chicago
    Messages: 146

    Once the valve covers are off, make sure you put rags in the head to block the oil gallies so IF you drop the old seals they don't fall into the engine. Do you know the sequence for tightening the rockers? That is also a critical but easy step. I can't explain it but their are videos on YouTube that show you exactly how it is done.
     
  18. MickiRig1

    MickiRig1 PlowSite Veteran
    Messages: 3,617

    Leave the push rods in-place,if you remove them keep them in order to where they go.
    Little dabs of grease on the inside of the keepers on the valve shafts help to keep them in-place. Make sure you have the book or know the procedure for torquing down the rocker arms. Clean all the sealing surfaces well and wipe down with solvent/paint thinner/brake cleaner/etc so it will seal well. Before you put the valve covers on. Unplug the coil so it will not start. Wind the engine a few times and make sure all the valve keepers have stayed in-place. Then install the valve covers. Don't forget to plug in the coil.