Head problem-Pushing the cap out of the back of head. HELP!!

SO this has happened to me about 3 times now, and it is never consistent. The first time it happened last November and i didn't think much of it, just that the cap might have been worn out. So i bought 2 and just tapped her back in, this lasted until the middle of the summer, and it came out again. So this time I tapped it back in, and sealed it with some ultra black.
On my lunch break today, it happens again, i pull in the drive way, and oil is pissing everywhere, and its smoking like a damn locomotive from the old west movies.
Why is it doing this, and what the hell can i do to fix it?
Any help would be great.
Thanks

pcv valve maybe. pop it out and make sure it rattles.

pcv sounds like its junk and your building too much pressure