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Camper_Jeff___K's avatar
Camper_Jeff___K
Nomad III
Feb 14, 2025

Leaking Expansion/Freeze Plugs

The engine is in the truck and runs great. MPG with TC was 9.4, nothing to especially write home about. The problem I'm having is coolant leaking out of 2, possibly 3 plugs. 1 left, 1 right, and possibly 1 on the left rear of the block inside the bellhousing. With 3 leaking, it calls into question if any of the 4 plugs behind the timing cover, inside the engine are leaking. There is no evidence in the oil of any sort of leak. Dots of coolant on dipstick, or froth. I have a 180 degree thermostat in now and the engine temp is at 169 degrees solidly. I'm going to install a 195 thermostat today, and I figure that will raise the running temperature to 180-185 degrees. The machinist, engine builder says they build all their engines with the same sealant, a non RTV sealer, and that it may leak for a while but should seal by 500 miles. I have 200 now. He says if there is a problem, they have a way to seal the plugs. Not Barsleak.

I posted a 4 minute video on my CITAP1 YouTube channel if anyone's interested in seeing the leaks.

Updates coming.

  • Camper_Jeff___K's avatar
    Camper_Jeff___K
    Nomad III
    Mar 14, 2025

    Break-in period isn't completed yet. The machinist tells me he has a way to deal with the problem. I'll give him a chance to make it right before I try something else. 

    • Grit_dog's avatar
      Grit_dog
      Navigator
      Mar 14, 2025

      No point in being intentionally vague here. You posted a detailed account of this issue presumably to share. 
      You haven’t asked your “machinist” what his magic solution is?  Or you’re not sharing it?
      So you’re going to drive down to Portland to figure that out?  
      This just doesn’t make sense unless you’re just secretly hoping the issue resolves itself rather than addressing it and checking this off the list or adding it to the list. 
      Strange approach. 

       

      • Camper_Jeff___K's avatar
        Camper_Jeff___K
        Nomad III
        Mar 14, 2025

        That is a very strange response! I'm hiding nothing, nor am I being intentionally vague. I give information as it develops. I'm following the machinists instructions, it's his build and warrantee so I'll follow that. I said he has a fix called T-Block if the plugs don't seal. Having just talked with him, he refers to it as a Rebuilders Block. It comes in the shape of a cube, dimensions unknown, it will be here next week, and I am to crush it and pour into the reservoir. It will circulate through the engine and he says will seal any leak, period! He says it will not cause any clogging issue with the radiator or heater core. He says manufacturers put this in new vehicle engines as a precaution. II can't find anything on the internet called T-Block so I'll just have to see what it is when he sends it. You know everything about what's going on as I do up till now. Next update will be when I get the stuff and install it, then wait and see what happens. Until then, be patient. I'm hoping for a happy ending. The engine is running great thus far otherwise...

  • Camper_Jeff___K's avatar
    Camper_Jeff___K
    Nomad III
    Feb 28, 2025

    I'm waiting till the end of the break in period. If there is a problem, the builder says to contact him and he has a fix for the leak. The leak has slowed but not completely stopped. We'll see how things turn out.

    • Grit_dog's avatar
      Grit_dog
      Navigator
      Mar 07, 2025

      I guess you kinda need to play along with the seller for warranty, however sounds like you’re hoping for a miracle and avoiding the reality of it. Freeze plug sealant doesn’t cure more  or expand or migrate over time. 
      the only way a leak path would seal is via radiator sealant, a high concentration of minerals in pure water “clogging” the leak or divine intervention. 
      But you know this, unfortunately. And the warranty was useless in this situation because it doesn’t cover labor and it’s easier to fix than taking the engine somewhere to put in a new freeze plug or 2. 
      Bummer, man. 

  • Grit_dog's avatar
    Grit_dog
    Navigator
    Feb 23, 2025

    Jeff, you smarter than to think that any coolant leak will “fix itself”. Including freeze plugs. 
    Im sorry to hear you have an issue with a brand new engine but the builder is just trying to limit his liability and playing in the fact that you really don’t want to rnr an engine again and may bite on some “fix”, but you have a problem. And if those problems are not accessible without pulling the engine or trans, you already know what the solution is. 
    I love wrenching on stuff as a hobby as well. I do not typically enjoy required major work. Don’t have the time. So hopefully you have more of the latter because leaking freeze plug in bell housing = pull the engine. 
    And the line about drive it more, the leaks will heal is laughable. 
    How many new cars come out with coolant leaks that the fix is “drive it more it will heal?”  
    This is a bummer dude. 

  • StirCrazy's avatar
    StirCrazy
    Moderator
    Feb 15, 2025

    how bad are they leaking?  I have never had a freeze plug leak so I am wondering what they use to get them to seal.  

    • Grit_dog's avatar
      Grit_dog
      Navigator
      Mar 07, 2025

      Freeze plugs gotta come out. And reinstall with sealant. There is not proper in-frame fix for inaccessible ones. 

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