Head Gasket Problem?

[callmewaylon]

Changing valve seals on my '82 K25. On the last cylinder, after having the air hose hooked up to the spark plug hole for a few minutes I started to hear bubbling. Turned out pressure was building in the radiator. I took the cap off and released the pressure and bubbles and coolant were coming out. I'm thinking I may have a cracked head or bad head gasket? It wasn't showing any symptoms of a bad head gasket before this. Any ideas?

 

[Deuling]

In a properly sealed engine, I dont think the coolant system should share any pressure with the compression system.... So id say you have problem. Maybe you just pushed more pressure in than what the coolant system does and you are only seeing a blow by because of that (which would still mean you have a bad spot)....