I have a 2000 Accord with 180K on a V6 motor. I hear a whining noise when engine is warmed. When I remove the dip stick or loosen the oil cap or open the PCV valve, noise goes away. I have replaced the PCV as well as EGR. I AM assuming it’s pressure building up and PCV should be working as it’s replaced twice now. I am thinking it might be valve cover gasket? Any thoughts or suggestions?

(Timing, Water Pump and best etc have been replaced.)