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Head gasket or ...?

Discussion in '308/328' started by yelcab, Jun 5, 2020.

  1. yelcab

    yelcab F1 World Champ
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    #1 yelcab, Jun 5, 2020
    I am working on this 3.2L engine. The timing belt covers and belts have been removed and I noticed there is green coolant coming out from one of the holes where the long bolt goes into the block.

    First picture shows the big picture, second picture shows the close up of the hole where there is coolant.

    You can see the profile of the head stud behind the hole. If I remember correctly there should not be coolant where the head studs are.

    Compression test was done on bank 1 and it was good. Spark plugs look clean and no misfiring so there is no coolant in the combustion chamber. No milky oil, no oil coolant either. So, is it just leaking into the blind hole and out the threaded hole?

    Opinion? At least a head gasket, right?

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  2. thorn

    thorn F1 Rookie
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    #2 thorn, Jun 5, 2020
    A combustion leak test would be my next step.
     
  3. yelcab

    yelcab F1 World Champ
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    #3 yelcab, Jun 5, 2020
    I think I will do another coolant pressure test, and watch this hole.
     
  4. AZDoug

    AZDoug Formula 3

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    #4 AZDoug, Jun 5, 2020
    Off topic question about that pic.

    I see there are backing plates on the cam belt covers my 308 does not have.

    It that to keep people from somehow sticking their finger in there with running engine and then suing Ferrari when their finger is torn off? Or just general debris guard to keep stuff out of there?

    Doug
     
  5. Steve Magnusson

    Steve Magnusson F1 World Champ
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    #5 Steve Magnusson, Jun 5, 2020
    Last edited: Jun 5, 2020
    +1 -- could also be porosity/crack in the block into the water jacket rather than a head gasket problem -- is that better? ;)

    If putting the bolt in (with some sealant) stops the leak (and it hasn't been leaking) = why not? Coolant leaking at the head gasket into the head stud(s) isn't really an operational problem, and besides, there's a reason getting the heads of the studs is a *****. ;)
     

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  6. yelcab

    yelcab F1 World Champ
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    #6 yelcab, Jun 5, 2020
    Oh bite your tongue Steve. A cracked block is not better. And, I would consider sealant to stop the leak. This is a non-combustion related, non-fatal leak.
     
  7. yelcab

    yelcab F1 World Champ
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    #7 yelcab, Jun 5, 2020
    They go back and forth over the utility of the backing plates. Some have it, and some don't, and it does not seem to make a bit of difference.
     
  8. mike996

    mike996 F1 Veteran

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    #8 mike996, Jun 5, 2020
    Makes good mechanical sense to have backing plates to keep parts/debris from dropping in un-announced! Can't imagine it ever had anything to do with fingers - at least back then. Nowadays someone could sue claiming the stress of seeing exposed belts caused them some trauma which, fortunately, could be successfully treated/cured with an award of some cash.

    Re the bolt - I would do as suggested, a pressure test on the cooling system, observing that fitting. If it shows leakage/pressure drop, I'd install the bolt with some sealant and repeat the test. If there is no leakage (pressure drop) with the sealant, I'd apply sealant to the bolt when completing the belt change and forget about it. ;)
     
  9. yelcab

    yelcab F1 World Champ
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    #9 yelcab, Jun 5, 2020
    I am just thinking out loud, if I sealed up that bolt hole. What are the chances of the coolant having no place to go, working its way up along the head stud, and seeping out into the head?
     

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  10. Steve Magnusson

    Steve Magnusson F1 World Champ
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    #10 Steve Magnusson, Jun 5, 2020
    Last edited: Jun 5, 2020
    The upper end is fairly well-sealed, too, with the good machining, precision flat washer and (closed) acorn nut. A drop, or two, of coolant entering the engine oil system every year, or so, wouldn't be a disaster -- that's probably already happening elsewhere anyway ;)
     
  11. yelcab

    yelcab F1 World Champ
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    #11 yelcab, Jun 10, 2020
    I am going to close this out.

    I dug into the head and found two (out of ten) head nuts loose. Both nuts needed an additional 45 degrees of turn before they get back to 100 Nm. After being retorqued, pressure test was applied for 2 hours with no more leaks. I then drained the block and saw that the water level in the bolt hole remained the same. That tells me there is no crack or porosity in the block where the water seeped through.

    I vacuumed out the water from the hole, and will apply sealant to close it off. But I think the source of the leak was the head nuts being loose. An inspection of a picture of the head gasket shows a coolant channel very close to the head stud chamber. So if the head nut is loose, the water would find its way to the head stud chamber.
     
    Jdubbya likes this.

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