yes take a look at your pcv valve first before ruling out blow-by. other than pcv valve also check your air filter element for engine oil residue. for oil pressure to be relieved, it has to go out somewhere else to prevent the engine from exploding. inspect and clean pcv muna...

btw, have you noticed something else to your engine's performance. mahina hatak, white smoke on tailpipe, too much engine oil, nababawasan ng engine oil????