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Thread: Head Gasket issue?

  1. #11
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    Join Date:  Mar 2012

    Location:  Texas

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    Quote Originally Posted by dn010 View Post
    What kind of pressure tester are you using? I have a tester that is on the cheap side and if I do not put a large o-ring into the neck of whatever I'm testing, the "cap" of the tester will leak causing the pressure to drop.
    I just used a rental from an auto parts store. I don't think there was an issue here-- I felt as though it was holding pressure reasonably well.

    Quote Originally Posted by dn010 View Post
    Also - I believe there is a test where you start the engine (cold) with the tester installed and watch the gauge while revving, if there is a jump in pressure it indicates a leak - I'll have to check the instructions when I get home to be sure this is what it was.
    I did this and there was no jump in pressure. Don't know if the thermostat has to be open or not...

    Quote Originally Posted by dn010 View Post
    When the smoke is spewing out of the exhaust - does it have an odor? Smell like fuel? Oil?
    I haven't really noticed. Wondering if its fuel since all of my spark plugs were black! This would be a preferable issue. =)

    Quote Originally Posted by dn010 View Post
    Blue smoke or burning oil while revving along with the fact you have 135 in a cylinder before you added oil to the cylinder to me would mean an issue in that cylinder such as pitting inside the cylinder from sitting especially if you have a coolant leak, or a piston ring issue.
    This would make me very sad.

  2. #12
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    Quote Originally Posted by Ron View Post
    Dead cold and engine off, it should hold a couple of minutes. If you then crank it up, pressure should not rise right away (ie not until the heat would make the coolant expand...) If the needle wiggles while the engine is running, you are seeing the signs of compression leaking into the coolant system.
    It held! And no needle wiggles.

  3. #13
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    Quote Originally Posted by David T View Post
    One test that will unequivocally tell you if you popped a head gasket is a combustion gas test. You test the coolant for any sign of combustion gasses. Easy to do. Other tell-tale signs include emulsion on the plastic screen in the oil filler, evidence of water in the oil, shiny deposits on the spark plugs, always adding coolant with no external leaks. Do you know if the motor was ever overheated? See if the plastic screen is still in the oil filler and if it looks melted. Another way to tell is to hook up your pressure tester and see if the pressure rises quickly when the motor is running. Be careful not to exceed 17 psi or you WILL pop something important.
    I don't know if the motor was ever overheated by a PO, but I've owned it 10 years and it's run reliably until now. The screen on the oil filter is still there! Seems to be in good condition.

    I'll look into the combustion gas test. Thanks!

  4. #14
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    Quote Originally Posted by bluscreen View Post
    I'll look into the combustion gas test. Thanks!
    Are there any recommended products here? The ones I've seen on Amazon appear to need access to the top of the radiator.
    Thank you!

  5. #15
    DMC Midwest - 815.459.6439 DMCMW Dave's Avatar
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    Location:  Taylors SC

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    Quote Originally Posted by bluscreen View Post
    Are there any recommended products here? The ones I've seen on Amazon appear to need access to the top of the radiator.
    Thank you!
    Top of the coolant header bottle is functionally the same place. That will work fine. Sometimes not as conclusive as I'd like but we've used that as a test.
    Dave S
    DMC Midwest - retired but helping
    Greenville SC

  6. #16
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    My engine got hot one too many times, and I noticed that, when the engine would cool off after driving, I'd get a coolant leak from the head gasket to the outside of the engine. I thought I'd have to replace the head gasket, but a trusted mechanic with many years of DMC experience said to check the head bolt torque, and re-torque them if any are below spec. Sure enough, a few of my head bolts were looser than they should have been and my problem has been fixed since.

    The chocolate milk antifreeze makes me suspect that oil and coolant are mixing somewhere. White smoke on startup could indicate that there is a leak at the head gasket(s) into the cylinder, but if it goes away, the thermal expansion of the engine could seal up the leak just enough (like it did on my car).

    If the compression increases with oil in the cylinders, that points to a piston ring that is going bad. That could also cause the blue smoke. But, it doesn't seem like it's bad enough to warrant an engine rebuild. Fresh oil that doesn't look like chocolate milk could also help this issue.
    -Derrin

    5786: DPI cams and cat-less exhaust, galvanized and powder coated manual frame for a proper 5-speed conversion

    3196 - My wife's DeLorean: DMCH new build, DPI rebuilt engine with performance cams and exhaust

    1956 Oldsmobile Super 88
    1960 Chevrolet Impala
    1961 Corvette
    1972 Buick Skylark GS 455 Clone
    1975 Corvette (to be sold once restored)
    1976 Corvette (wife's car)
    1979 Corvette Daily Driver
    1987 Corvette (technically wife's car)

  7. #17
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    It's finally been warm enough for me to start working on my car again.

    I took a valve cover off and all of the head bolts were extremely tight. A torque wrench set to 50 ft. lbs didn't budge any of them, too.

    I was able to start the car.. not too much on the white smoke this time but it idle hunted very badly and clacked every now and again. Eventually it died-- it feels like it's not getting enough fuel to me.

    I'm wondering if I should just start a new thread listing the symptoms. I'm at a loss here and I'm feeling like there are numerous problems all happening at once.

  8. #18
    EFI'd dn010's Avatar
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    Start by going over your fuel components again - if you've had gas with ethanol in it sitting in the tank for the past 5 months, get it out and put in fresh fuel, check the pump and hoses. Check over your lines and make sure everything is tight and you don't have any vacuum leaks. After that I'd probably test the injectors and see what they look like. Make sure everything else is good before you go tearing down your engine to replace head gaskets when you don't have to.
    -----Dan B.

  9. #19
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    Quote Originally Posted by dn010 View Post
    Start by going over your fuel components again - if you've had gas with ethanol in it sitting in the tank for the past 5 months, get it out and put in fresh fuel, check the pump and hoses. Check over your lines and make sure everything is tight and you don't have any vacuum leaks. After that I'd probably test the injectors and see what they look like. Make sure everything else is good before you go tearing down your engine to replace head gaskets when you don't have to.
    I think I've been through most of this.

    Tank was completely cleaned out, new fuel pump installed... new fuel filter. Fuel with cleaner/stabilizer has been run through the system. Injectors spray test well.

    I'm not sure how to properly check for vacuum leaks without purchasing really expensive equipment. Would a vacuum leak really cause this much havoc?

  10. #20
    EFI'd dn010's Avatar
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    A small leak won't do much but a large leak can cause problems. The vacuum hard line going down the frame to the front of my car had rusted out and caused all kinds of issues I could not figure out until I went to change frames. You can pull the hose off the main vac nipple on the back passenger side of the intake, plug the nipple and see if that changes anything. The rest should be easy to inspect, check the lines for cracks, follow them and make sure they're connected, etc. You may or may not find something, but at least you can check that off your list and keep going without having to spend any money or much time on it if you find nothing wrong.
    -----Dan B.

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