A tight mechanical seal on any of these plugs is what was intended originally from the MoCo as evident of how the plug was constructed.
However, when one of them leaks, it's not always cost efficient or convenient to have the threads repaired especially if your on the road with a badly leaking or blown out plug.

• Below is a collection of ideas for sealing up the plug until a solid mechanical seal can done.
  If the health of the threads on the plug or in the case are questionable, only tighten the plug to just snug, plus a little.

• Try a thread wrap just under the head of the plug.
  Use only enough to get a seal. Using too much could crack the case from the extra pre-load plus normal torque.
  • Wrap some sewing string just below the head of the plug. ¹⁾
  • Wrap some Teflon tape below the head. It's intended use is for tapered pipe threads, ²⁾ and the OEM plugs use straight threads.

• Try a thread sealant. Clean the plug and the hole of all oil and debris to get a good sealant hold.
  • If the threads are not stripped (as in a bad sealing surface causing the leak), Loctite (blue) can be used as a sealant between the threads.
    However, if the threads are stripped or are in bad shape, they may break off upon the next removal of the plug.
  • Cover the plug with silicone, put the plug in the hole, turn it to get a wedged fit and let it dry.
  • Cover the plug with JB weld and let it set for about 2 days. ³⁾ (you might want to use something else if you plan to remove the plug later).

• Add a washer or O-ring to the plug.
  • Copper washers work well for sealing and the thin ones work much better than the thick ones. They meld in there better. ⁴⁾

• Source a temporary plug.
  • A cork in the hole has been used with various results. Be sure to have an extra or two on hand in the case that the first one blows out.
  • Put a rubber expansion plug (like the ones used for auto freeze plugs) the hole. ⁵⁾