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Thread: Coolant Leak Issue

  1. #1
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    Coolant Leak Issue

    So I have a coolant leak that only comes up if I run the car long enough to start building heat in the engine, but not long enough to open the thermostat. If I drive home from work (maybe 2 miles) it'll leak a cup or two from the bottom side of the engine, but if I drive it around all day looking at houses, it doesn't leak a drop. It shouldn't be the water pump, as I already replaced that, it did it before and after I replaced it. When I got the car, it had a 14lb radiator cap, it's been replaced with a 16, but I've been debating if I should try and go back to the 14. I haven't been able to find the leak, as getting the car up in the air is a bit of work (lowered, so it doesn't fit on ramps, and by the time I break out the jack and stands and get it up, it's done leaking). Anybody ever seen one do something like that, or have any advice on tracking it down?

  2. #2
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    'bottom side of the engine' is a pretty general area. Left or right? Front or back? Could be one of the heater hoses at the oil filter exchanger on the front, or up near the valve covers on either side leaking/spraying coolant to a different locale than the leak itself, could be a freeze plug.

    Quote Originally Posted by nomind View Post
    by the time I break out the jack and stands and get it up, it's done leaking). Anybody ever seen one do something like that, or have any advice on tracking it down?
    See if your local autozone has the cooling system pressure test suitcase you can rent.

    And I'd stick w/the stock pressure cap. Don't get creative, including a lower than stock temp thermostat.

    Lowered SCs can run hotter, so be sure the chin spoiler and radiator side baffles are in place.

    Strange it would leak only inside such a short drive. I'd wonder if the leak is like a pin hole that sprays down a panel when parked, collecting into a cavity that eventually dumps on a short drive with the car in motion, wash/rinse/repeat.

    Have you checked the A/C condensate drain to see if it's plugged up at all?
    Last edited by KMT; 07-22-2018 at 12:25 AM.

  3. #3
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    It's leaking from the front lower portion of the engine (under the water pump), you can see it dripping pretty heavily. The car itself doesn't run warm, so I'm not planning on making any drastic changes. As for the thermostat, the only thought I had there was to get one with a small bleed hole in it for passing air bubbles. I'll try the pressure testing kit from AZ this weekend.

  4. #4
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    Sounds like it leaks when the engine is mostly cold, but the coolant is heating/expanding (causing system pressure to increase)....then when fully warm, expansion helps seal the leak.

    Since you've replaced the water pump recently....

    Are you sure all bolts are torqued properly? What did you use for the gasket / sealant?

    Also likely would be a leak at the timing cover mating surface and/or bolts.
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  5. #5
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    Quote Originally Posted by nomind View Post
    It's leaking from the front lower portion of the engine (under the water pump), you can see it dripping pretty heavily..
    Since it was a before/after water pump install issue, again, in that example, I'd wonder about the hoses that come in/go out to feed the exchanger. Also thermostat housing to intake, as those are chronic, typically after the housing as been R & R'd, tho.

    How would you define the general cooling system's condition, otherwise? Eat off it? Rode hard put away wet? Always something?

    A pressure test should help isolate.

  6. #6
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    Quote Originally Posted by DrFishbone View Post
    Since you've replaced the water pump recently....
    Quoting TG, 'nobody reads the thread...'

    He said it was leaking before the new water pump

  7. #7
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    Quote Originally Posted by KMT View Post
    Quoting TG, 'nobody reads the thread...'

    He said it was leaking before the new water pump
    ...makes ya wonder at times.

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  8. #8
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    Quote Originally Posted by KMT View Post
    Since it was a before/after water pump install issue, again, in that example, I'd wonder about the hoses that come in/go out to feed the exchanger. Also thermostat housing to intake, as those are chronic, typically after the housing as been R & R'd, tho.

    How would you define the general cooling system's condition, otherwise? Eat off it? Rode hard put away wet? Always something?

    A pressure test should help isolate.
    I'm leaning toward the exchanger hoses as well, I didn't crack open the thermostat housing. Not that it couldn't be the thermostat housing, since I've never owned it while it isn't leaking (bought it not running). Radiator is older brass, but looks to be in serviceable condition. Main hoses all look in good shape (no cracks, not soft, no ballooning), I haven't gone over the smaller heat exchanger hoses (oil cooler, heater core, etc.) but will try to do that this weekend and see what else isn't up to snuff. Cooling system has been drained and refilled, but I don't remember what the coolant looked like when I drained it.

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