I had a frost plug failure a few days ago.. We did an engine over-all a couple of years ago and put in new 45 mm convex frost plugs at the same time.. The frost plug on the manifold side and nearest to the firewall began spurting anti-freeze out.. There was no steam or any indication of a leak until I saw the heat gauge.. I heated the engine up as I didn`t know what was going on.. When I filled it with water and started the engine it sounded fine and seems to have the same power as before.. Anyway,, I followed your advice and put the Permatex hardening sealer on the counterbore in the block and did the best I could at pounding the plug in,, not easy as there is no room to swing the hammer.. Will the Permatex help hold the plug in incase I did not do a good job of pounding the plug in ?? My brother in law put the plugs in with the engine over-all and it dosn`t look like he used any sealer.. I do not want to blow a plug again..