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Thread: Head Gasket issue?

  1. #1
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    Head Gasket issue?

    Hello all,

    Any suggestions on the next step from here?


    I've had my car around 10 years and recently I let it sit for 4-6 months. It had been mechanically reliable until then.

    Initially it would not maintain fuel pressure. After some troubleshooting I discovered the fuel pump's filter was completely clogged with goo. I cleaned out the tank, replaced the pump with DeLorean's new electronic one, and replaced the fuel filter. Seemed to fix the issue but now, if it sits for a while, a LOT of white smoke pours out the tail pipes right after I start it. Also, it's idle-hunting a lot. Especially if it rev the engine.

    Besides that, if I give the car a decent amount of gas while sitting in neutral it will blow a fair amount of blue smoke out the tailpipes.

    I have run a pressure test on the coolant reservoir tank and it showed normal, but I wonder if this is because the thermostat was closed. I also ran a compression test on the cylinders-- each got about 150 psi except one was 135 and the one next to it was 140. However, I was able to raise the 135 one to 150 by putting a teaspoon of oil into the cylinder. I hope this doesn't mean anything terrible.

    The spark plugs, which only had about 2k miles on them, were all very black. I can't tell if its carbon or oil. It looks ever so slightly shiny but not really gummy or wet.

    Lastly, when I changed the oil, the very last little bit came out like chocolate milk. Picture attached. Maybe it's just sediment? The car had been sitting for a couple weeks.
    I broke open the lowest coolant connection and drained about a quart out but it looked very clean-- didn't look like there was any oil in it...

    Sorry for the long post. I really appreciate the help here. I've read a few older how-tos on replacing the head gasket and it seems pretty involved.

    deloreanoil.jpg

  2. #2
    User title. Soundkillr's Avatar
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    You sure the smoke on startup isnt oil? Sitting for a while, and smoke on start up can be valve guides.
    Soundkillr was here.

  3. #3
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    Quote Originally Posted by Soundkillr View Post
    You sure the smoke on startup isnt oil? Sitting for a while, and smoke on start up can be valve guides.
    I'm pretty sure it's not oil since its so white, but I'm not positive.

    If its valve guides, is that something that might be fixed with a fuel cleaner additive? Maybe to remove some gunk there? Or is this something that would have to be fixed with the head off?

  4. #4
    Admins Never Retire Ron's Avatar
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    White smoke can be easily confused with steam, caused by condensation in the exhaust. Since you have changed the oil and made the above checks (They sound ~normal. No, closed thermostat doesn't matter for the test.), I'd suggest you install a new set of plugs and keep the engine running until it warms up. Let it cool, then take a look at the plugs to get your best clues at this point. (Keep track of which cylinder they come from...)

  5. #5
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    Quote Originally Posted by Ron View Post
    White smoke can be easily confused with steam, caused by condensation in the exhaust. Since you have changed the oil and made the above checks (They sound ~normal. No, closed thermostat doesn't matter for the test.), I'd suggest you install a new set of plugs and keep the engine running until it warms up. Let it cool, then take a look at the plugs to get your best clues at this point. (Keep track of which cylinder they come from...)
    OK, will do! This sounds like a great idea.

    Since it was quite a bit of white smoke, it is still a possibility that coolant is getting into a cylinder. Would this show on the spark plugs?

  6. #6
    Admins Never Retire Ron's Avatar
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    Plugs that look particularly cleaner than the others is a sign of coolant getting into the combustion chamber.
    I should of mentioned that the current plugs might tell a lot too...

    P.S. How long did the coolant pressure check hold and at what pressure?

  7. #7
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    Quote Originally Posted by Ron View Post
    Plugs that look particularly cleaner than the others is a sign of coolant getting into the combustion chamber.
    I should of mentioned that the current plugs might tell a lot too...

    P.S. How long did the coolant pressure check hold and at what pressure?
    The current plugs were all very black (at least the part in the combustion chamber). They looked ever so slightly shiny so I couldn't tell if it was carbon or oil. I would guess carbon. None of them were even remotely cleaner than the others... so this makes me feel better (in regards to coolant leaking in).

    When I pumped the DeLorean's coolant system up (from the bottle) to 14 psi, it dropped 1 psi after 15 minutes, 2 more at 30 minutes, and 4 more at the 90 minute mark.

  8. #8
    EFI'd dn010's Avatar
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    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.

    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.

    When the smoke is spewing out of the exhaust - does it have an odor? Smell like fuel? Oil?

    While white smoke typically means a coolant leak into the cylinder (as stated above not to be confused with the condensation vapor while it's cold). However there was once where my fuel distributor was damaged and dumped a ton of fuel into the cylinders, that caused lots of white smoke but that was also accompanied by raw fuel pouring from my exhaust onto the ground.

    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.
    Last edited by dn010; 11-27-2017 at 04:13 PM.
    -----Dan B.

  9. #9
    Admins Never Retire Ron's Avatar
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    Quote Originally Posted by bluscreen View Post
    When I pumped the DeLorean's coolant system up (from the bottle) to 14 psi, it dropped 1 psi after 15 minutes, 2 more at 30 minutes, and 4 more at the 90 minute mark.
    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.

  10. #10
    Delorean Guru
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    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.
    David Teitelbaum

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