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Coolant leak 308 intake manifold

Discussion in 'Technical Q&A' started by Dandy_Don, Jul 1, 2004.

  1. Dandy_Don

    Dandy_Don Karting

    Dec 8, 2003
    102
    The Woodlands TX
    Full Name:
    Don McCormick
    Hi,

    My intake manifolds leak coolant (slightly) where they bolt onto the head. Of course I decided I could not live with it and have pulled the manifolds and cleaned up the surfaces and am wondering what sealant or coating I should use in addition to the new gaskets which I have ordered? They were assembled with what looks to be a blue RTV silicone and leaked. Any help or recommendations would be appreciated. Thanx Don
     
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  3. ria

    ria Formula Junior

    Nov 2, 2003
    725
    ohio
    Full Name:
    phill
    i just did my intakes on my 308 gtsi i use the ultra gray RTV a thin coat of RTV on both sides of the gasket will be fine.
     
  4. atlantaman

    atlantaman Formula 3

    Mar 31, 2002
    1,726
    Roswell, Georgia
    Full Name:
    Charles
    the intake manifolds do not have any coolent in them--if they do--you have BIG problems--it if is the coolent rails that are below them then you just need new gaskets, rtv sealant, and a wire brush to clean things up
     
  5. snj5

    snj5 F1 World Champ

    Feb 22, 2003
    10,213
    San Antonio
    Full Name:
    Russ Turner
    the early cars actually do have a coolant passage with the intake manifold. later cars have the separate coolant manifold.
     
  6. ria

    ria Formula Junior

    Nov 2, 2003
    725
    ohio
    Full Name:
    phill
    on my 1980 308 gtsi on the intakes ther is 2 hose that conect the 2 intakes and water pass in them for cooling the hads and on. a thin coat of RTV ultra gray is to be use .
     
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  8. Matt Morgan, "Kermit"

    Matt Morgan, "Kermit" Formula Junior

    Nov 12, 2003
    405
    Ferndale, WA
    Quite right on the water passages in the 2 valve motors, as they have a passage that runs along the flange, and exits in the center. I would surmise that it is a remnant from the Carb models, as a means of helping keep the carbs from iceing up. I often find that they can be quite corroded, often to the point that a gasket sealing may be questionable. I cure the problem by a thorough cleaning, followed by a layer of good ol' JB Weld, applied with a flat blade. They can be carefully hand filed if there are any high spots once it is cured,so that the surface is flat, and true.
    HTH
    Kermit
     
  9. Dandy_Don

    Dandy_Don Karting

    Dec 8, 2003
    102
    The Woodlands TX
    Full Name:
    Don McCormick
    Thanx all, I will try a bit of JB weld on some of the pitted surfaces on the head and the manifold flange. The manifold castings have a surprising number of voids or low spots in the casting, none near the edge but close enough that I think that I will fill them with JB weld and then sand/file smooth. While it seems that gray RTV is the goop of choice, has anyone ever used the liquid copper gasket sealant made by Permatex for this application? It is formulated to seal head gaskets so it might just stop the collant leaks. Again, thanx Don
     
  10. Matt Morgan, "Kermit"

    Matt Morgan, "Kermit" Formula Junior

    Nov 12, 2003
    405
    Ferndale, WA
    Right on Don. I'm with Ria on the Ultra Grey. SPAREINGLY. Any axcess that squeezes out should be left untouched, as after it cures, it wil peel off, leaveing no traces of sealant, and a clean looking job. Any yhat may end up in the runner will be washed off by the petrol over time, and will not hurt the internals on the motor. The coolant passage is a different story, as it will end up in the radiator, causeing havoc, hence the SPAREINGLY.
    Kermit
     
  11. Verell

    Verell F1 Veteran
    Consultant Owner

    May 5, 2001
    7,000
    Groton, MA
    Full Name:
    Verell Boaen
    Permatex makes a grey colored RTV just for waterpump/coolant sealing applications. It's called:
    PERMATEX® Water Pump & Thermostat RTV Silicone Gasket Maker
    http://www.permatex.com/auto/autouh.asp?automotive=yes&f_call=get_item&item_no=22071

    Spec sheet says it's much more resistant to coolant than the other RTVs & it's rated for 600 degrees F continuous.

    http://www.permatex.com/MSDS_data/tds_files/22071.pdf


    The copper gasket sealant is good for high temp applications, but I don't think it's a good fit for here.
     
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