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block heater sealant?

Discussion in '80-Series Tech' started by IdahoDoug, Dec 8, 2003.

  1. IdahoDoug

    IdahoDoug

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    Well, the advantages of a dry climate accrued to me today. I had to retighten the block heater as it's still seeping. In order to get a full size screwdriver on it I had to remove the rear manifold heat shield. With limited space, I had to use the small 1/4" drive and had little leverage. Amazingly, they popped loose easily after 10 years!

    Anyhow, if this final tightening still allows seepage I'll have to remove it and consider a new gasket and/or sealing options. Anyone have a suggestion on what to use to seal a rubber gasketed brass block heater into a cast iron block? Something that can be removed at some point, I hope.

    DougM
     
  2. cruiserdan

    cruiserdan SupportingVendor Emeritus Moderator

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    Doug,

    I don't have an answer for you but I have a suggestion who to ask. Block heaters are ubiquitous in the Diesel community. How about asking a nearby HD truck repair place what they use?


    D-
     
  3. Landpimp

    Landpimp

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    Doug. Stupid question but where is your block heater mounted? I thought they replaced a feeze plug?
     
  4. cruiserdan

    cruiserdan SupportingVendor Emeritus Moderator

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    John,

    That is correct. The heater occupies a freezeplug hole. It has an odd-looking o-ring around the edge and a molly bolt-looking-thing on the back to secure it in the block.

    Doug's is seeping around the edge.
     
  5. Landpimp

    Landpimp

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    [quote author=cruiserdan link=board=2;threadid=8586;start=msg73620#msg73620 date=1071027339]
    John,

    That is correct. The heater occupies a freezeplug hole. It has an odd-looking o-ring around the edge and a molly bolt-looking-thing on the back to secure it in the block.

    Doug's is seeping around the edge.
    [/quote]

    Hmm I thought they were just pounded into the hole.......at least my 78 fj55 one looks like it is.
     
  6. IdahoDoug

    IdahoDoug

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    Pimp, if you look closely you'll see a screw head under the plug.

    Well, looks like it's still seeping. I'm thinking it might be best to remove it, clean out any crud accumulated from seepage in the freeze plug hole, and replace the O ring before reinstalling. Anyone know if the O ring needs to have any special properties (oil resistant, temp resistant, synthetic, etc)?

    Thanks!
     
  7. IdahoDoug

    IdahoDoug

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    The seepage seems to occur upon startup in the morning and I was feeling uneasy that there may be another leak. So I waited for the truck to cool, then went out this evening and started it. Got under the truck and immediately saw a thin trail running out of the block heater. So, good that this is the leak, but things just got a little more urgent on my request for O ring conditions. Anyone have an opinion? Are their "upgrade" O rings out there that can handle anything? Obviously spending $3 on one vs 78 cents is not an issue if I don't have to ever remove the block heater again, so that's what I'd like to do.

    DougM
     
  8. Rich

    Rich

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    http://www.oringsusa.com/html/elastomers.html

    Use some silcone grease to lube the oring. The purpose of the lube is not to block a leak but is to enable the oring to move as necessary to form a good seal between the block & plug.
     
  9. IdahoDoug

    IdahoDoug

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    Great site! Looks like EDPM is the material I'm looking for. They have a neat little diagram that helps you decide based upon the operating environment and conditions. Now I've gotta bite the bullet and pull it out - essentially disabling the vehicle until I find the proper size/material O ring.

    Thanks, Rich!

    DougM
     
  10. Scamper

    Scamper

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    Doug,

    I've been using this stuff for years:

    http://www.duniway.com/images/pdf/DC-150-datasheet.pdf

    It's virtually indestructable and works great on sealing o-rings; it's so thick that it helps to keep things in place during assembly too. One tube lasts a heck of a long time (I've had one now for about 10 years). It will beat out any grease you'll find for longevity and resistance to heat and chemicals.

    Tom
     
  11. IdahoDoug

    IdahoDoug

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    Well, major crisis averted by being a little aware of my vehicle. Pulled the block heater out of the block and found the O ring had rotted a bit. Atop that, it uses a toggle like thing that flares out inside the block as you tighten it, and the reason it began leaking more after I tightened it is the brass toggle thing had cracked and failed. Must have overtightened it, but still I'd have expected brass to bend rather than kinda crumble. Fortunately all chunks accounted for.

    Called CDan for O ring advice. Found an O ring that fit, then further cannibalized the Supra block heater I've had laying around forever to replace the toggle thing. Stuffed the thing back in, replaced the 1.3 gallons or so of coolant that ended up on the garage floor and it's good to go.

    Also got tired of listening to the scratchy sound of the horn rim contact when I turn the steering wheel now that it's cold. Fired a spot of white lithium grease onto it via the blinker stalk hole and now that's quiet again. Only does that when it's really cold, now it won't for another 5 years...

    DougM
     
  12. Beowulf

    Beowulf

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    Tom,
    And where would a Smart Shopper find some of that Dow Corning grease?
    -B-
     
  13. Scamper

    Scamper

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    [quote author=Beowulf link=board=2;threadid=8586;start=msg74359#msg74359 date=1071120911]
    Tom,
    And where would a Smart Shopper find some of that Dow Corning grease?
    -B-
    [/quote]

    B: don't know about the Smart Shopper part, as this stuff is a bit spendy, but one tube will last forever since you don't need much to do the job. Here's a place you can get it on the internet.
    http://www.2spi.com/catalog/vac/dow.shtml
    I got mine many years ago at a local lab supply shop. It is/was designed for use in a chem lab for sealing glassware surfaces under vacuum and that sort of thing. One warning: if you get it on something you don't want it to be on, it's VERY hard to get all of it off--the stuff is tenacious. In the lab, the way we would remove it was by soaking the glassware in a concentrated dichromate-sulfuric acid solution (very nasty).

    Tom
     
  14. Beowulf

    Beowulf

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