Coolant leak from head bolt?

Small Block Mopar Engine

  1. b5cuda

    b5cuda Well-Known Member

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    Hey guys, got a small coolant leak that appears to start at the front driver's side head-bolt (the one closest to battery tray). No sign of coolant in the oil. Does this bolt pass through the water jacket? I'm wondering if I should just pull it, seal, and torque it down again. I'm hoping it's that and not a head gasket. Running standard fel-pro gasket with less than 10,000 miles. Engine is 318 with 273 closed chamber heads. Just resealed ex-manifold studs and don't think anything is leaking there. Thanks for any help ya'll can offer!
    Bill
     
  2. jomoper

    jomoper Mope or Nope

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    Never mind My previous comment,I guess I can't read today .
     
  3. green1

    green1 Well-Known Member

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    If it ain't exhaust stud, start over.
     
  4. racerhog

    racerhog RacerHog likes his Mopars

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  5. RedFish

    RedFish Well-Known Member

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    I cant remember seeing a head bolt going into a water jacket on a 318.
    That doesn't mean there isn't one.
     
  6. 67Dart273

    67Dart273 FABO Gold Member FABO Gold Member

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    Gauwd, Red, let's not start this again, LOL. I have a couple of blocks out in the garage that are "wet."

    This is a photo that I personally took. That is my hand shining a light into a hole, and the light returning out a head bolt

    [​IMG]

    [​IMG]
     
  7. txstang84

    txstang84 Well-Known Member

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  8. jos51700

    jos51700 Green Bearing thread connoisseur

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    It's probably just me, but I never understood how pouring stuff in the coolant to plug small holes didn't negative affect the radiator which is...full of small holes.
     
  9. txstang84

    txstang84 Well-Known Member

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    I'd probably give the same explanation you've already heard so I'll forego it, but I can speak from my own experience it sealed up a leaky t-stat housing on my wife's car and its been holding for at least a year...the key is driving 25 miles or so after putting it in.

    If you ask why I didn't just change the gasket, it's on a 4.6 and I didn't feel like pulling the intake.
     
  10. moper

    moper FABO Gold Member FABO Gold Member

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    The sealer is supposed to react with air - kind of like you blodd when it clots. The down side is there can be some trapped air, and some sealers have so much solids that they do plug heater cores and readiators. The cores don;t flow as fast so normally it's them that get clogged up.
     
  11. jos51700

    jos51700 Green Bearing thread connoisseur

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    Well, I don't know if there's any truth to it, but that's actually a pretty plausible explanation.
     
  12. RustyRatRod

    RustyRatRod I was born on a Monday. Not last Monday. FABO Gold Member

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    I put sealer on every head bolt on every engine I build, blind hole or open. It seals the open holes and helps to act as anti seize when you disassemble. Seen a few broken head bolts through the years. It helps cut down on those. They suck.
     
  13. 68gtxman

    68gtxman I used to reMember

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    Me too. I like to use the liquid Teflon sealer. Never had a leak.
     
  14. b5cuda

    b5cuda Well-Known Member

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    Great thoughts gang - I will in future use sealant on headbolts. However, I am having second thoughts whether the leak is from the headbolt or the ex. manifold stud. I haven't see any water/steam coming from or around the x-stud (this coolant leak only seems to appear at road speed), so I assumed it was a headbolt leak. But on closer inspection, the location of the coolant trail (white residue) could possibly be coming from either source. So I will rule out the x-stud first. Pulled it today, once dry I will re-seal with RTV and let it cure for a day and a half before refilling coolant and firing. Hoping this does it - will let you know!
     
  15. Bad Sport

    Bad Sport HALF A BUBBLE OFF Staff Member FABO Gold Member

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    I don't think I would use RTV, I would use some non hardening thread sealant.
     
  16. racerhog

    racerhog RacerHog likes his Mopars

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  17. RustyRatRod

    RustyRatRod I was born on a Monday. Not last Monday. FABO Gold Member

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    That's all I've ever used. High temp RTV. Never had one problem. A bottom tap cleans threads right up. I've seen that liquid teflon goine on teardown. Not a trace. Every time I've done teardown with RTV, it's always still there doin its job. I even use it on head bolts such as in my Ranger I just got done with. There are 4 steps to torque them down and they are stretch to yield, but I use it anyway. Some may argue it changes the torque and it may, but as many as I've used it on, I've never had a problem related to head bolt clamping force. It's just good insurance.
     
  18. Bad Sport

    Bad Sport HALF A BUBBLE OFF Staff Member FABO Gold Member

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    Hmm.... I've always been told it would dry and leak.
     
  19. 2 Darts

    2 Darts A-body Addicted

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    There are twenty bolts that hold on an LA cylinder head. Eighteen of them are the same length. The 2 longer bolts go through the rocker arm oil gallery. These bolts go on the top row. 2d from the rear on the right hand cylinder head, 2d from the front on the left. Swapping the long bolt for one of the short ones will leave at least 2 points improperly torqued. Could water from one of these migrate into a bolt hole? Yeah, could be.
     
  20. b5cuda

    b5cuda Well-Known Member

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    Update... I resealed the exhaust manifold stud with RTV (which has worked for me in past, unless there's an issue with fitment), torqued it, let it sit a day and a half and... that did not stop the leak.
    Checked the torque on the first two lower head bolts on that corner and they are tight and do not show any residue from a leak at the head. Where I am seeing the coolant pooling is on that little flat lip/ledge that sticks out on the driver's side front corner of the block, just below the head. So at this point I am thinking it must be either:
    (a) the x-stud is still leaking (I believe that hole has a heli-coil inserted so that could account for it)
    (b) the head gasket is leaking (there is a water passage near that front corner, at least my bare 340 block has one there so I assume the 318 does also), even though it has less than 10,000 miles on it (standard fel pro gasket, 273 closed chamber head).
    Not crazy about pulling a head until I know I need to, and there are no other signs of blown headgasket. So I'm debating whether to just live with the slow leak for now? I'm all ears if anyone has any ideas I'm not seeing... thanks!
    Bill
     
  21. b5cuda

    b5cuda Well-Known Member

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    Further update... tried the permatex thread sealant on that x-manifold stud and it made no difference. Guess I need to pull the head to get to the bottom of what's leaking - the helicoil or the head gasket. Since it's a small leak I will probably keep driving through the fall, then pull it this winter. Or maybe that's the excuse I need to swap in the 340 I'm building!
     
  22. racerhog

    racerhog RacerHog likes his Mopars

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    Something must be cracked...
     
  23. 67Dart273

    67Dart273 FABO Gold Member FABO Gold Member

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    How many? Mine only has 10
     
  24. Snake

    Snake Mopar Nut

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    I had the same problim once in the same area,mine turned out to be leaking from my intake manifold,left side at the rear,worth a look.
     
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