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Thread: Blown Head Gasket - DIY? what else to inspect/replace?

  1. #1
    Junior Member JCochrane's Avatar
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    Unhappy Blown Head Gasket - DIY? what else to inspect/replace?

    So my DeLorean sat still for a few years, and didn't really want to start for us after all that time. Eventually got it running by push-starting it, enough to move it to its new garage (~1hr driving). On the way, though, I noticed when I'd push down on the accelerator, it'd kinda sluggishly get around to accelerating - not at all responsive like it used to be (at least for an old & heavy car). I chalked it up to bad gas at the time.

    Diagnosed the startup problem and ended up replacing the original starter (finally). Started right up, but then huge plumes of white smoke. Ok, back to the bad gas problem (or so I thought)... Pulled open the gas tank access and stuck my phone in access w/ flash on - gas looks fine - no major 'floaties' or sediment or anything. Ok... google 'white smoke'... oh crap.

    Now I'm pretty sure I have a bad head gasket, and I'm hoping that's it for the moment. Correct me if I'm wrong

    So it looks like a few hundred in parts and either a few grand in labor or, using the procedure on dmcnews, a good 8-10hrs (or more) of meticulous tear-down and rebuild. I think I'm up for the challenge, unless you'd recommend having a shop just do it at this point. I didn't have any issues with the starter or getting into the fuel tank, and have done lots of other miscellaneous things to it, but nothing this major.

    Oh, and the modified/expanded procedure calls for a custom angle-aluminum bracket to keep the timing chain, and implies it's a bunch more work without it, then at the end says it's probably better to do it without the bracket and just redo the timing... thoughts on that?

    Also, while I'm at it, what else should I really consider replacing or at least inspecting? I'm not super interested in dumping a ton of money in it at this point, so I don't want to go hog-wild replacing every sensor and tube, but if there are some things to look for in particular it makes sense to do it while in there already. I think the water pump was replace 10-15 years ago at this point, for what it's worth.

    Thanks!
    Josh
    v7120

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    Modern fuel is bad within a year or less. The absence of debris doesn't indicate the quality of the fuel.

    Unless the car has been severely overheated multiple times it's unlikely you have a blown head gasket, especially if you were able to drive for more than 10 minutes

    You most likely have a fuel delivery issue. Symptoms, diagnostics and repairs are all discussed on this forum.

  3. #3
    Senior Member
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    Quote Originally Posted by Ethan Rode View Post
    Modern fuel is bad within a year or less. The absence of debris doesn't indicate the quality of the fuel.

    Unless the car has been severely overheated multiple times it's unlikely you have a blown head gasket, especially if you were able to drive for more than 10 minutes

    You most likely have a fuel delivery issue. Symptoms, diagnostics and repairs are all discussed on this forum.
    This!

    I would drain the fuel by siphon. Look what you got then. Clean what you can. If it wasn't too bad, put new fuel and unhook the return line turn the pump on. Pump it till it looks clean. Then MAYBE it will be better.

  4. #4
    Junior Member JCochrane's Avatar
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    The car has overheated, at least once with me, but that was years before it was put on ice, so to speak (fan relay went out in ~80F city driving, overheated and spewed coolant all over). My dad owned the car before me and said he wasn't surprised when I suggested it looked like the head gasket was blown.

    The coolant level is dropping a bit when it runs as well, which coupled with the dense white smoke and sluggish/lower power seemed to make sense as a head gasket.

    I haven't done the oil change yet, but I gather milky-oil is a good indication of coolant leak as well. Should I start with an oil change? I was going to do that after replacing the gasket. Or can I tell just by draining a little oil if it's milky? Do I need to run the engine for a bit first to 'stir it up'?

    Or should I continue down the fuel system route? I bought a bunch of carb cleaner expecting to drain the tank and spray a bunch of that in there to clean it out, so I think all I have to do is activate the pump relay to drain the tank (though perhaps not best to pull the old gas through all the lines?), and then clean the tank and replace the fuel filter?

  5. #5
    EFI'd dn010's Avatar
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    You should start by pressure testing the cooling system to rule it out instead of guessing.

    Ethanol fuel goes bad much faster than a year, it is stated to last up to three months but I notice it go bad in a month of sitting or sometimes less like three weeks. You can try running some cleaner additive in your fuel and replace the filter if it's been a while. The last time I had white smoke with K-jet, my fuel distributor was shot and dumping way too much fuel into the engine.
    -----Dan B.

  6. #6
    Junior Member JCochrane's Avatar
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    That sounds a lot easier than head-gasket will do some research, thanks!

  7. #7
    EFI'd dn010's Avatar
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    I should clarify my post to say if you don't know how old the gas is, get it out of there. Then you can change the filter and run the clearer through to see what happens. I clear the tank by removing the hose from the pump (which may be difficult if you have original plastic lines, mine are rubber), install another rubber fuel line routed from the pump to a fuel container and then jump the pump or relay.

    As far as pressure testing, you can get a tester on amazon or rent it from a store such as autozone.
    -----Dan B.

  8. #8
    Junior Member JCochrane's Avatar
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    Thanks for follow-up!

    I'm assuming you had to replace your fuel distributor, then?

    Is the pressure-tester good for anything else, or just radiator? I see the MotoRad MT-300 mentioned here, and it's about $80, but if it's single-purpose it probably makes sense for me to borrow at this point, especially with an Autozone about 15 mins from me, so I'll try the rental option. Though in that thread, they also recommend buying it and using it once or twice a year, so...

    If I'm replacing the fuel filter anyway, can I just unplug the distributor feed hose and drop that into the gas can and pump the gas through? I've seen that suggested round here as well, which then doesn't require you to open up the tank again; though I suppose I have to open the tank to clean it out anyway, so... :shrug:

  9. #9
    EFI'd dn010's Avatar
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    Yes, at the time I did have to replace the fuel distributor.

    The pressure tester has no other uses and unless you work on multiple vehicles, it makes more sense to rent one than to buy one.

    There are multiple ways to evacuate the fuel from the tank, I only did it the way I did so that I wasn't pushing more crap down the lines. Go with which ever way you find it to be easier for you as long as you can reach your goal of removing all the fuel. It wouldn't hurt to check the tank once it's empty and check the hoses/pre-filter and wipe up any debris off the bottom.
    -----Dan B.

  10. #10
    Junior Member JCochrane's Avatar
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    What about the oil route as well? I purchased the EZ Oil Drain Valve Kit from DPNW, so I figure I could pull the drain plug and install that and get at least some idea of the quality of the oil. I don't recall offhand if I need to drain the oil fully to install that plug or if I can sorta do it quick enough to get it back on without causing too much of a mess. I suspect with the engine cool the oil & water will have separated back out, so I guess I probably won't know if it's 'milky' until I drain it empty, or perhaps run the engine for a few minutes to mix it up?

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