I had a cam seal leaking on my 97 Montero 3.5L V6 140,000 miles.
When I got in to it I found the cam seal on the left side had popped out of the head. Put a new seal in with a little no. 2. Right side looked like the seal was not in as far as it should be. Replaced it also, I pushed it in with my fingers! Put it all back together, major oil leak right cam seal. I think it popped out. These new seals were from NAPA, Chinese made. Ordered and received new OME seals today.
Has anybody else had problems with these seals? Doing it twice is bad enough don't want to do it a third time!

Did you use any kind of sealant?

Yes, put a little no. 2 on the outside of the seal.

In reality, they aren't under pressure from anything. The only thing that could be causing it I believe is crankcase pressure. PCV?

Well, put new seal in today. Nothing had popped out.
Not sure why it was leaking. Seems to be good now.
Did replace PCV just for the heck of it. New seal did fit tighter than the ones from NAPA.