Blown Head Gasket vs Bad Intake Gasket? How to diagnose? Coolant in Oil!!!

Discussion in 'Fox 5.0 Mustang Tech' started by FastGT94, Apr 24, 2006.


  1. FastGT94

    FastGT94 New Member

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    Ok, so I took off my intake the other day to replace a ticking lifter. Got that done, bolted it all back up, re-stabbed the dizzy and started the car.

    I wound up setting the timing to ~20* advanced on accident (timing light set wrong) :nonono: :nonono:

    Anyways, took the car out, it was stuttering and pinging like crazy. Turn around take it home, and re-do the timing. Now everything's fine.

    Forward ~one week later, I'm getting bubbles in my coolant overflow tank while running and immediately after shutdown and I have coolant in my oil. I also had an oil leak from my intake at the back so I thought the gaskets weren't done right.

    So I re-do the intake gaskets and I am still getting bubbles in my overflow tank and coolant in my oil.

    So I guess my question is, with the timing too high is it likely that I blew my head gasket? I know how to check for a bad head gasket but how can I be sure its not the intake gasket?

    I'm pretty good on the head gasket testing procedure.
    -Compression test on all cylinders look for two that have similar levels (lower than the others) or look for one dead cylinder. And that's your bad spot.

    But my problem started when I took the intake on and off so I'm wondering if my problem is really to do with the intake gasket instead. Is there any test that would properly diagnose a bad intake gasket vs. a bad head gasket?

    Any other tips for figuring this out would be most appreciated! I'm going to run a compression test tonight.

    Thanks,
    #1
  2. poneypower89

    poneypower89 Now everyone in the world will know I wanna bang t

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    Well, if you changed out your head gaskets.. and you are still getting coolant in the oil just as you did before... Then is likely you have warped or possibly cracked your heads. Most of the time the warping or cracking is so small you wont notice it unless you look really hard. If the heads are just slightly warped you can have them re-surfaced at a machine shop and you will be right back in business....

    I dont know how you managed to do it.. but its possible pinging and detonating ran the engine too hot... hot enough to damage your heads. Its exactly what killed of my Firebird a few years ago.
    #2
  3. FastGT94

    FastGT94 New Member

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    It didn't get too hot, I had my eye on all the gauges.

    I actually just swapped the INTAKE gaskets, not the head gaskets. ;)

    Thanks!
    #3
  4. poneypower89

    poneypower89 Now everyone in the world will know I wanna bang t

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    Wow, I really need to read better.. Im sorry man. That post probably made me sound like an idiot. I just assumed you said head gasket instead of intake gasket.

    Well, I dunno what say.. sept at least go and check ur head gaskets :rolleyes: That way you wont keep asking. :rlaugh:
    #4
  5. FastGT94

    FastGT94 New Member

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    LOL, just making sure you read it right. I understand what you're saying there though, makes sense.

    I'm still hoping its an intake gasket but I doubt it at this point...
    #5
  6. 1Bad88notch

    1Bad88notch New Member

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    I had the same problem with coolant in my oil too. I thoguht i had a bad intake gasket but it turned out to be a head gasket. Do a pressure or leak down check on it and listen to see where it is coming from and go from there. the water port on the head gasket blew and was running into the oil port. GOOD LUCK!!!
    #6
  7. FastGT94

    FastGT94 New Member

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    Ran a quick cooling system pressure test at lunch and it held 16 psi fine for well over 2 minutes. Still have to try it while running to see if there is any fluctuation with the the needle.

    If not, I'll have to move onto the leakdown test.

    I'm definitely going to do this again just to be sure but that needle wasn't moving during the cold test.
    #7
  8. 1Bad88notch

    1Bad88notch New Member

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    I would also drain your oil too and see how much water is in there. You could a warped head or crack in it that you can't see
    #8
  9. FastGT94

    FastGT94 New Member

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    ok so here's the update, and I feel dumb.

    The coolant in the oil I was experiencing was a little residual leftover in my oil/air separator that had been freaking me out. I changed the oil last night after letting it run for a while and there is zero coolant in it.

    Secondly, the bubbles in the overflow tank are due to a faulty radiator cap, not a blown HG. I found this when testing the cap and it only holds 14 lbs, not 16 like it should.

    Finally, I ran the cooling system pressure test with the engine running for about 20 minutes and I get zero fluctuation of the needle on the gauge.

    So looks like I'm ok since all the tests passed ok except for my radiator cap which will be replaced today.

    Thanks for all who helped, I'll go back to my corner now for freaking out too early LOL... :)
    #9
  10. 8950HO

    8950HO New Member

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    Did you retorque the lower intake after running it a while?
    This is pretty much mandatory on these cars and it can take two or more retorque sessions until the lower intake finally seals.
    #10
  11. DMAN302

    DMAN302 My mom says thanks for the pearl necklace.

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    Always should change the oil when doing an intake replacemnet...good job on finding the issue and fixing it!
    #11
  12. FastGT94

    FastGT94 New Member

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    I had changed it but this was in a separate reservoir. But yes definitely should have done that LOL
    #12
  13. Foxfan88

    Foxfan88 My Grandpa has great wood.

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    lol reminds me of the one time i thought my engine was locked up but it was actually my starter.
    #13

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