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Excessive Oil Consumption.. Excessive!

Discussion in 'Early CJ5 and CJ6 Tech' started by JesseG, Sep 20, 2012.

  1. Sep 20, 2012
    JesseG

    JesseG New Member

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    Has anyone experienced excessive oil consumption with almost no smoke? About a quart of oil every 65 miles! It is the F-head engine. Checked for crankcase pressure, have none. Maybe the intake valve seals, maybe the PCV valve? I am looking for some feedback from someone who may have experienced and /or fixed an issue like this. I see a little smoke cloud after a long decel but not like an old Chevy pickup/mosquito truck. Breather tube is unobstructed and a quick test actually proved a vacuum existed in the crankcase, not pressure. Chime in!!
     
  2. Sep 20, 2012
    PeteL

    PeteL If it wasn't for physics, and law enforcement... 2024 Sponsor 2023 Sponsor 2022 Sponsor

    Hills of NH
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    Vacuum pump diaphragm? It connects intake to the crankcase if perforated.
     
  3. Sep 20, 2012
    Jw60

    Jw60 Sitting up n buckled down. 2024 Sponsor 2023 Sponsor 2022 Sponsor

    Sedalia MO.
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    this sounds crazy, but...
    are there little dots on your tailgate?

    mine would fill the oil bath with mist from the crank case and leak from there.
     
  4. Sep 20, 2012
    Walt Couch

    Walt Couch sidehill Cordele, Ga. 2024 Sponsor 2023 Sponsor 2022 Sponsor

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    If you have a mechanical oil gauge you may have a broken line loosing oil down the hi-way.

    If you have electrical gauge it could be leaking at higher pressures while traveling.
     
  5. Sep 20, 2012
    JesseG

    JesseG New Member

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    Naaah, no leaks, but driving it tonight with cars behind me(headlights) I realized the smoke clouds are a little thicker than I thought. I just need to figure out if it's the pcv valve or the valve seals. Anyone ever did valve seals in one of these? We are gonna run an experiment with an oil catch can in the pcv line and see what we catch.
     
  6. Sep 20, 2012
    Jw60

    Jw60 Sitting up n buckled down. 2024 Sponsor 2023 Sponsor 2022 Sponsor

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    PCV valve seals? or intake/exhaust valve seals, because i don't think it has valve stem seals.
    manifold vac test, compression test, (look for wet plugs) pull the line from the intake or look down the carb into the head bolt area and check for oil, also check if vac wipers are working slower than norm at idle or decel.
     
  7. Sep 1, 2017
    haighfam

    haighfam Member

    Paradise, CA
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    Dragging up an old post. I'm on my Oregon trip. Discovered it was using oil, about a quart every 100 miles. Since I have limited options, removed and cleaned the PCV valve. It had a lot of oil in it. Checked the exhaust with a paper towel before any work and it would blacken immediately, after there was very little. Any thing else I can do?Running great otherwise, has good power and getting 15-17mpg.
     
  8. Sep 1, 2017
    PeteL

    PeteL If it wasn't for physics, and law enforcement... 2024 Sponsor 2023 Sponsor 2022 Sponsor

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    Post #2 above. If you still have dual pump.

    But why are you asking, if the exhaust is now clean?
     
  9. Sep 1, 2017
    haighfam

    haighfam Member

    Paradise, CA
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    I have the dual pump, was freshly rebuilt. Just kinda concerned because I have a 520 mile trip ahead of me and that was all I was able to do. At the rate it was going it would take me 2 gallons of oil to get home.
     
  10. Sep 1, 2017
    mayday

    mayday Sponsor

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    I had some issues on mine, turned out to mostly be drain issue back into crank case. Are you checking oil every time you stop or start of the day?
     
  11. Sep 1, 2017
    mayday

    mayday Sponsor

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  12. Sep 2, 2017
    Mark Wahlster

    Mark Wahlster Member

    Silverton, OR
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    I had a 1988 Ford F-250 with the EFI 460 engine. The manifolds were cut at the wrong angle. It would burn a quart of oil in 175 miles with absolutely no smoke.

    It was pulling the oil up out of the galley under the manifold and pulling it in with the intake charge. There by getting a clean burn unlike oil left on the cylinder walls from bad rings which does not burn at full temp.

    I got so pissed at the Idea of having to tear 500lbs of crap on the top of that engine off to put the special wedge shaped gaskets they made to patch up the mistake I sold the truck at a HUGE loss. One of the few vehicles I have ever bought that I didn't get my moneys worth out of it.

    Course on a good day the POS only got 9.5-10 mpg. My Dakota on the other hand has 185K gets about 800 miles on a quart and commuting gets 18.5mpg and on long trips will see 21 mpg at 70mph. And fits through a DQ drive through like a family sedan.
     
    Last edited by a moderator: Sep 2, 2017
  13. Sep 2, 2017
    PeteL

    PeteL If it wasn't for physics, and law enforcement... 2024 Sponsor 2023 Sponsor 2022 Sponsor

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    I suppose I would pull the plugs and see if any one cylinder might be having a problem, or if it is system-wide. Maybe do a compression test while I'm there.
     
    Vanguard likes this.
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