So, I have about 3k miles on this engine and a few months ago, it popped a freeze plug out when rolling into boost. Once the weather got warm, I put it back in and it blew out again. I performed a leakdown test and it showed 30% 40% 45% 50% front to back. Seeing that, I replaced the headgasket. However, that did not fix my issue. Came into boost a couple of times and POP! Coolant exits engine. It is the freeze plug right above the oil filter. I put black RTV on it the first time and the second time I used high tack gasket sealer. Any ideas?

Thanks in advance!

 

Fix your cylinder leakage.

 

I see no mention of post headgasket leak down numbers. You probably have a cracked bore or head.

 

rtv wont hold a freeze plug in either. it's probably too small for one.

and for two, indian head shellac is the bomb.

 

Seal 'em Freeze Plug

 

black RTV is for oil. Ultra Grey is what you should have tried.

but it sounds like youre still pressurizing the coolant system and that's the weak link.

 

Check for hydrocarbons in cooling system pleaze.