Crankcase ventilation

[DavidPHumes]

I should mention: although I don't have the normal symptoms (overheating, water in the oil, loss of water, smoke, etc.) I have a gut feeling that my HG is bad (I have had a rubber cap blow off of my lower tstat housing twice but once was because it was dry rotted and the other was because it was a 2 piece cap so it's tough to say why it happened). Can this cause excessive pressure? Compression is 165 across the board cold, 150 warm on all 4.