[Bunkie314]

I have had these damn plugs out numerous times to try and seal them. I have tried about every sealant that exists and still cannot get them to stop leaking. I even bought a tap, modified it, and chased the threads. I don't dare thread them tighter due to breaking the casting (2 TFFT rule of thumb and I am around 2-1/2) and wonder what the *%$$ to do next. After a few heat cycles they start to leak around the threads again. I am not sure where to go at this point. Its not big leaks, just weeping and I have to top off periodically.

Anyone else have this kind of issue with threaded freeze plugs in an aluminum block?

Should I just keep tightening them until they seal? The 2-1/2 turns is pretty damn tight.

Any recommended coolant system stop leak additive? I have been considering using Copper Coat.

I'm really frustrated with this as I cannot get a permanent seal. Sealant works (Caterpillar Form-A-Gasket has been the best and longest lasting so far) for a 100 miles or so.