Engine Hg Blown, Possible Cause, Look At This Pic Please!

Discussion in 'Fox 5.0 Mustang Tech' started by madspeed, Sep 27, 2013.


  1. madspeed

    madspeed Colonel Mustard Mod Dude Founding Member

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    Hey guys, as i posted in another thread, I've recently discovered a blown headgasket at cylinder number 5. No oil in coolant, and no coolant in oil, it was only driven about 3 miles when i heard what sounded like the header gasket leaking. While investigating a bit, i noticed the head stud at that cylinder was wet with oil, and inside the exhaust chamber it was pretty black with a bit of oil buildup, as both can be seen in this pic. The other cylinders look different, just like normal exhaust pipes look.


    [​IMG]

    You can see the metal sticking out where the gasket blew out in this pic.

    [​IMG]

    What is this telling me??

    THANKS
    #1
  2. 84Ttop

    84Ttop They make new pistons every day, so why worry? SN Certified Technician Mod Dude

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    Really doesn't look like a big deal. I would pull the heads have them resurfaced install some new gaskets and rock and roll.

    Things to consider after you fix it. How much boost? How much total timing under full boost? Where is the a/f under boost? Any signs of detonation? How do the plugs look after a WOT pass?
    #2
  3. madspeed

    madspeed Colonel Mustard Mod Dude Founding Member

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    Boost is 10 psi, total timing i'll have to check on, afr under boost is 11.5- 11.6, no signs of detonation, plugs look normal, even the one pulled from that cylinder. Seems to die off a bit around 5000 rpms, but no dropoff in boost or afr

    what would cause the oil pooling on the exterior of the stud? Maybe a bad gasket to begin with or improper torquing?
    #3
  4. Casey2552

    Casey2552 Member

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    To me it looks like a bad valve seal or guide and header gasket went bad and blew the oil on to the bolt ,, ????
    #4
  5. madspeed

    madspeed Colonel Mustard Mod Dude Founding Member

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    header gasket did not blow, sounded like it, but was fully sealed when removed and i found the hg sticking out as pictured
    #5
  6. Casey2552

    Casey2552 Member

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    Oh yeah I see now , got to take it apart to find out , hopefully nothin maybe just a bad head gasket damaged maybe when installed and a new one will be good if your lucky but if it was mine , lol it would have a hole In the piston and scoured cylinders , that's my luck
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  7. Casey2552

    Casey2552 Member

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    MIt looks like there's a lot of oil build up in there , I think there has to be a problem in valve , maybe on top side " seal or guide " or oils comin threw the bottom of the valve , I think that would mean possible ring failure in that cylinder..also if the pushrod bent and valve was not opening could that cause excessive presure for that cylinder just a thaught
    #7
  8. Casey2552

    Casey2552 Member

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    I would pull valve cover and rotate motor over and see that rockers are working properly before you disassemble , making sure the lift and duration appear to be the same as other cylinders
    #8
  9. 84Ttop

    84Ttop They make new pistons every day, so why worry? SN Certified Technician Mod Dude

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    @Casey2552 where are you coming up with all of this? I seriously doubt there is a cam problem and what does that have to do with a head gasket? The valve seals leak oil onto the outside of the head stud?? Am I reading this right? Certain valve seals in my heads have been removed for a reason and i have no trouble....
    #9
  10. Casey2552

    Casey2552 Member

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    Geuss you know what your talking about , here's a cookie

    Attached Files:

    #10
  11. MikeH686

    MikeH686 Mine is only two inches though.

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    ^^dic k thats why @84Ttop has a boosted vehicle and talks from experience bolst plays alot of roles in the dilemma if it was a bad seal he would have a blue smoke
    #11
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  12. Casey2552

    Casey2552 Member

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    Well then I guess only your opinions matter , no big deal I didn't come on here to argue with to guys that are good at what they do
    #12
  13. 84Ttop

    84Ttop They make new pistons every day, so why worry? SN Certified Technician Mod Dude

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    At least it wasn't oatmeal raisin...
    For the future I prefer Doritos @MikeH686 @TOOLOW91
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  14. Casey2552

    Casey2552 Member

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    Lol I will remember that , and to everybody I know very little just the things I would check , it was only an idea not a recommendation , I don't know **** about boosted cars , but an here tryin to learn like everyone else
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  15. madspeed

    madspeed Colonel Mustard Mod Dude Founding Member

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    no smoke, no oil burnng. Just gonna order new gaskets and reinstall. I just wonder how/why oil was getting onto the stud, but i'll guess no big dealio
    #15
  16. mikestang63

    mikestang63 Mustang Master

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    Mad, all I can think of is the bad HG was allowing oil to get sucked up into that valve when it opened under boost. It seeks the path of easiest or least resistence. What's the combustion chamber and pistion look like?
    #16
  17. Rick 91GT

    Rick 91GT SN Certified Technician Site Sponsor

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    That's what I'm thinking as well


    Sent from my XT907 using Tapatalk 2
    #17

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