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Technical 56 Pontiac oil leak

Discussion in 'The Hokey Ass Message Board' started by flypa38, Apr 23, 2014.

  1. flypa38
    Joined: May 3, 2005
    Posts: 529

    flypa38
    Member

    Last year I found my road draft tube to be completely blocked at the filter. Oil was starting to leak from the breathers. So I converted to a PCV setup. Since then the engine is leaking from other places. I was hoping you guys could put me in the right direction on fixing my crankcase pressure and oil leaks.
    I remember hearing something about cleaning the road draft filter by setting it on fire and knocking the junk out in charcoal form. Can anyone elaborate on the process or suggest a better solution?
    Secondly, oil is filling the top of the valley cover. Any idea where it might be coming from?

    Do the new oil leaks seem like a result of crankcase pressure? I've been driving this car pretty regularly since I've owned it (about 8 years) and the leaks happened pretty suddenly.

    Thanks for any suggestions you guys can make.
    Johnny
     
  2. I have experienced oil leaking from the filter of my 55 Pontiac but only when it was due for an oil change.I change the oil every 3,000 miles anyway but for some reason it will start leaking when it is near due.After the oil change the leak stops.
    I have put nearly 180,000 miles on the engine in the 20 years I have owned it and have never cleaned the road draft tube.Have had minor leaks from valve cover gaskets which were easily cured.
     
  3. flypa38
    Joined: May 3, 2005
    Posts: 529

    flypa38
    Member

    Valve covers are starting to leak a little in the back too. I've never experienced what you're describing regarding the oil change. I only have about 600 miles since last oil change anyhow. If I had to guess though, sounds like the filter nearly being clogged and oil taking a path of less resistance. Could be my problem too!
    The one that's puzzling me is the top of the valley cover. What has oil in it that is above that level?
     
  4. Could be oil leaking from the intake side of the valve covers and leaking down onto the cover or possibly the bolts holding the cover are leaking.
     
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  5. flypa38
    Joined: May 3, 2005
    Posts: 529

    flypa38
    Member

    Thanks safariknut. I'll look there next.

    Anybody have a procedure for cleaning that filter?
     
  6. krooser
    Joined: Jul 25, 2004
    Posts: 4,585

    krooser
    Member

    Check the return holes in the heads for blockage… and in the valley. If the oil your using is dislodging years of sludge this could be your problem. Vacuum out as much of the debris as you can as you don't want that crap to plug the oil pump inlet.
     
  7. hoop
    Joined: Mar 21, 2007
    Posts: 585

    hoop
    Member

    Are you sure your PCV is set up correctly?
     
  8. stimpy
    Joined: Apr 16, 2006
    Posts: 3,547

    stimpy


    this , or the cork gasket dries out along the heads and allows them to seep . also if the draft tube is still connected it can be leaking from there . the draft tube unbolts from the block , to clean it soak it in solvent and coat hanger it from the engine side down and try to knock the stuff on the bottom out , I have seen the tubes stuffed with steelwool trying to control excess oil bypass . and it often gathers dust and turns into a brick . there should be a filter on it ,

    as for the PCV it should pull from the valley or from the cover opposite of the breather , and hooked directlyt to the manifold , and they make different weights for different vac numbers . I try to use one for a mid 70's 400 car .
     
  9. flypa38
    Joined: May 3, 2005
    Posts: 529

    flypa38
    Member

    Can't remember what the PCV is intended for. Best I can tell it's set up right. The PCV is installed where the road Draft tube used to go. Vacuum source is from the carb base. Does this sound about right?
     
  10. That's where Pontiac put the PCV when they installed them on these motors.
     
  11. Bruskie
    Joined: Apr 9, 2014
    Posts: 50

    Bruskie
    Member

    make sure you have a pcv for a v8 cuz one for a 6 or 4 cyl has too large of pintle in it not enough flow
     
  12. flypa38
    Joined: May 3, 2005
    Posts: 529

    flypa38
    Member

    I used Fram FV112DP. It supposedly fits a 79 400 cu. in. engine so hopefully it's right.
     
  13. hoop
    Joined: Mar 21, 2007
    Posts: 585

    hoop
    Member

    With engine running remove breather cap.Are fumes coming out? You do have a breather cap?
    PCV should be drawing fumes in.
     
  14. flypa38
    Joined: May 3, 2005
    Posts: 529

    flypa38
    Member

    Breather caps on both valve covers. Didn't have a chance to check for pressure at the caps yet, but I'll check that too. Thanks for the suggestions so far!
     

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