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A secondary method to test for a blown headgasket?

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  • A secondary method to test for a blown headgasket?

    Well, I was out tuning and managed to melt off the electrodes to two sparkplugs.(Cyl#2&Cyl#6)

    I knew something was up becuase the car dogged out and felt wierd.
    I nursed the car back to the shop and popped the hood. The coolant bottle was full and bubbling.(Temp. gauge and Nistune showed acceptable temperature)

    *I started the car, and pulled it into the shop and proceeded to pull the plugs and check compression.
    All numbers show ok.(1,2,3,4,5,6...145/145/145/140/150/145)
    I replaced the rad. cap and thought that might be the issue, drained the over flow back down and topped the coolant off, then let the car warm-up again.
    After it was warm, I rev-up the engine a few times and bubbles proceed to show in the overflow.
    I'm concerned and don't want to waste my time with a teardown if it isn't needed.
    *Shouldn't a blown headgasket show in the compression on a warmed engine?
    *Shouldn't I be getting alot of white exhaust?
    *The oil is the same color as usual, the coolant is the same color as usual...just this bubbling over flow bottle....??????
    **Ideas?, Opinions?, Alternate way to verify a problem here?
    I am here to help...

  • #2


    I just found this out.

    I stopped, but not soon enough. I found that by the time I got the wires off and the plugs out to do a compression check that the engine cools enough to not allow any signs of a blown head gasket.(so I figure??!) I do get a very small amount of whitish exhaust when I rev-up it up and let it drop to idle.(But that is hard as hell to tell for sure because it is friggin cold out and the exhaust is steaming anyways.)
    *Truth be known, the coolant overflow bottle will not show any bubbling action even when allowed to idle and warm up to the point where the e-fan cycles on/off. It only starts to show bubbling action after it is warm and I tug on the throttle a few times...from there on out, it will bubble.

    I wonder if it is worth the time to pull the plenum, and re-torque the head bolts(I haven't done this since I initially torqued them when it was assembled last) The engine has less than a tank of gas put through it now...
    I'd be so pissed to find that I pulled it apart to do the re-torque and wasted time/along with another upper plenum gasket, just to find out that the issue is still there.
    *How many people actually pull the plenum after the initial run-in to double check/re-torque the head bolts?
    RRRR..I might as well order another set of gaskets and just swallow the pride and pull it all back apart again.
    (Atleast the valve train and compression is good still & now I know that the amount of backpressure created from a clipped wheel and this set-up means that 16psi is the max!)
    I am here to help...


    • #3
      You could try retorquing, but I would just replace the head gasket and find out what caused the problem in the first place. Typically once a gasket deforms enough to let out pressure, a retorque will not fix the damage.
      Chuck Stong
      300+ Parts and Performance owner
      2002 ZCOT president and always active member