Elantra coolant leak

Discussion in 'Hyundai Elantra / Lantra' started by Navaidstech, Sep 12, 2007.

  1. Navaidstech

    Navaidstech Guest

    Hi all....

    I'm having a weird coolant problem with my Mom's Elantra. I believe
    it's a 96 model.

    Over the past few weeks she had noticed the car overheating. I didn't
    have much time
    to work on the car so I just kept filling up the reservoir and the rad
    with fresh liquid
    until such time that I was able to spend some time on the problem.

    So I got into it last night. I briefly pressurized the system to about
    30 PSI (probably too
    much) and found a small leak on the output of the thermostat.
    I fixed it by replacing the original hose clamp with a garden hose
    clamp, thightened it
    and the leak was gone.

    So I topped up the rad and the reservoir with water and off I went for
    a test drive.
    The outside temp was about 70 degs at the time.
    Within about 5 minutes of driving, the temperature gauge sat in the
    center of the
    Another 5 or 10 minutes went by and both rad fans came on (stopped to
    doublecheck), which
    I found weird since my Saturn doesn't do that unless it's hot out and
    I'm stuck in stop and
    go traffic.
    The needle sat pretty much in the center except for a couple of
    occassions when it went
    a little higher, but then dropped again.

    When I got home, I let the car cool down and noticed it was missing
    about a quart of water.
    Oil appears to be fine, there is no coolant smell in the car when
    running the heater, and
    the car doesn't blow white smoke.

    Pressurized the system again but could not find any evidence of a leak

    One thing that I have noticed (not sure if related to the above
    problem) was that the
    engine ran a little rough when stopped. The SES light in on constantly
    except for a couple
    of times it would flash when stopped at a light. Again, I'm not sure
    if it is related.

    I will be getting a scan tool to check for errors in the next couple
    of nights but until then
    I'm confused as to where the coolant might have gone.

    Any ideas I should look into would be greatly appreciated.

    Navaidstech, Sep 12, 2007
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  2. Navaidstech

    hyundaitech Guest

    The flashing check engine lamp will only occur when there is a misfire, so
    I'm figuring you'll have a misfire code at the very least. As far as the
    coolant, there are two main possibilities:

    1. There was an air pocket in the system and it moved to the top.
    2. The head gasket is leaking, possibly contributing to the misfire.
    hyundaitech, Sep 12, 2007
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  3. Navaidstech

    Navaidstech Guest

    Thanks for the info Hyundaitech... couple of questions:

    1. If the leak contributed to the misfire, would I not see foaming in
    the reservoir?
    2. As above, would the engine misfire all the time or when stopped
    only? The car runs great when it's moving. There are no misfires and
    the engine is very peppy. No hesitation whatsoever.
    Navaidstech, Sep 12, 2007
  4. Navaidstech

    hyundaitech Guest

    1. Probably not. Perhaps some bubbling when the engine got hot. A better
    test is to pull the plug on the offending cylinder and have a look at
    things. A clean combustion chamber is a sure sign of water/coolant in the
    combustion chamber.
    2. It all depends on how bad the failure is. You're in a high vacuum
    situation at idle. But, don't dismiss other causes. The ignition system
    is the #1 cause of misfires, but typically is worst under load. On the
    other hand, you may have a leaking intake gasket. That'd potentially
    cause a significant misfire at idle and nearly no misfire off idle.
    hyundaitech, Sep 12, 2007
  5. Navaidstech

    Navaidstech Guest

    Unfortunately (for me) you were right on both fronts.
    I scanned the computer last night and it showed misfire on #2
    cylinder. So I went to take the plug out to see its condition.
    In order to remove the plugs, I had to take the top cover off but
    first I had to unscrew the oil cap.
    Soon as unscrewed the cap, I looked underneath it and didn't need to
    proceed any further.... saw the light brownish deposit which obviously
    meant coolant in the oil, which probably caused the misfire, etc,

    Now... this is a 4 cylinder Elantra. I guess I'm looking at the head
    gasket, eh?
    Navaidstech, Sep 13, 2007
  6. Navaidstech

    hyundaitech Guest

    Don't assume the stuff on the oil cap indicates coolant in the oil. In
    fact, even when severely overheated, Hyundai engines/head gaskets rarely
    fail in that way. Most frequently, this milkshake-type goop is the result
    of short trip driving that causes condensation and doesn't allow it to burn

    Now for the bad news. If your head gasket is indeed leaking, you'll
    probably need a cylinder head. Very, very rarely do I see a case where a
    head gasket leaks from overheating and the head isn't warped beyond
    hyundaitech, Sep 13, 2007
  7. Navaidstech

    Navaidstech Guest

    To be honest with you, my Mom driving is pretty much limited to short
    trips. The oil cap isn't fully coated with the brown stuff and when
    you inside the rocker cover, the oil appears to have a typical oily
    I guess the best way to really make sure is to simply drain the
    crankcase a little and make the diagnosis then.

    Incidentally, with all the water the car is going through, you would
    think that the oil dipstick would reflect an increased volume of oil
    and water, correct?

    Also... is it possible that there would be no white smoke out of the
    tailpipe if the car would be going through a quart of water in a 45
    minute trip?

    deposits in it, but this may not be enough oil to
    Navaidstech, Sep 14, 2007
  8. Navaidstech

    hyundaitech Guest

    Incidentally, with all the water the car is >going through, you would
    No. As I said previously, this is not the typical cylinder head/head
    gasket failure mode on this engine. If you have a head gasket problem,
    the coolant is most likely leaking into the the combustion chamber, not
    the crankcase.
    Again, this depends on the size of the leak. Maybe.

    Once you know what cylinder is misfiring, pull that plug. Rotate the
    engine so that piston is at the top and look down in with your flashlight.
    If the piston is clean, you have coolant leaking into the combustion
    chamber. If it isn't clean, you should probably revisit more typical
    misfire and cooling system diagnosis procedures.
    hyundaitech, Sep 14, 2007
  9. Navaidstech

    Navaidstech Guest

    Did a couple of things today.
    1. Drained some oil from the crankcase. No trace of water in it, so
    you were right about the cap. Whew on that one.

    2. Pulled the offending plug and sure enough she was wet, so this is
    where the coolant is going into.

    Now a million dollar question: head or intake manifold gasket? Didn't
    have a compression gauge handy so I couldn't check. Will do that
    I'm also planning to pull the intake manifold tomorrow to check on the
    condition of the gasket there.

    Thanks for steering me in the right direction.
    Navaidstech, Sep 15, 2007
  10. Navaidstech

    hyundaitech Guest

    There's no coolant in the intake manifold, so it won't be coming from
    there. Unless there's something really weird going on (such as cracked
    head or block), the issue is with the head gasket. Expect that when you
    pull the head, it'll be warped beyond repair.
    hyundaitech, Sep 15, 2007
  11. Navaidstech

    Navaidstech Guest

    Bad news indeed.

    I don't think I'll bother with it then. The car isn't worth the
    trouble and/or the expense. Too bad because it ran quite nicely.

    Thanks for all the advice and pointers.

    Navaidstech, Sep 15, 2007
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