chassutton
Freshman Member
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Slight coolant leak from the plug after engine rebuild. Replaced with new plug from Moss and used "Permatex high temp sealer" but there's still a leak!!
The old plug top was flush with the head (as per factory installation as I understand it). The new one goes further into the hole by about 1/8 inch.
I've seen a few posts discussing such things as using alternate thread size plugs (12 TPI instead of 14), re-threading the head to NPI so as to be able to use a standard pipe plug (brass or iron) etc. However, nothing definitive. The techs at Moss suggest trying different thread seal materials (Hylomar?) but it seems shady to me to rely on thread sealer to prevent leaks from a pressurized system.
Ironically the engine rebuild projected started several years ago due to coolant mixing with engine oil (Cappuccino anyone?!). We assumed it was the head gasket or FO8 gaskets.
Any input, advice etc. for fixing the plug leak greatly appreciated.
The old plug top was flush with the head (as per factory installation as I understand it). The new one goes further into the hole by about 1/8 inch.
I've seen a few posts discussing such things as using alternate thread size plugs (12 TPI instead of 14), re-threading the head to NPI so as to be able to use a standard pipe plug (brass or iron) etc. However, nothing definitive. The techs at Moss suggest trying different thread seal materials (Hylomar?) but it seems shady to me to rely on thread sealer to prevent leaks from a pressurized system.
Ironically the engine rebuild projected started several years ago due to coolant mixing with engine oil (Cappuccino anyone?!). We assumed it was the head gasket or FO8 gaskets.
Any input, advice etc. for fixing the plug leak greatly appreciated.