'02 Regal- Severe vacuum in cranckcase

'02 Buick Regal w/3800 motor. When idling, I pull the oil cap off (takes some effort) and a rush of vacuum is sucking through the filler cap. Also hear a great amount of vacuum coming from the air filter box. Also...when hot...just coming off freeway, a loud 'whining' noise from the engine compertment like a pully bearing going. Some say PCV housing, but all looks good. Any ideas b/4 getting soaked by a repair shop? Thanks

When was the last time you changed the PCV valve? It is possible that it is clogged and it is causing too high a vacuum in the crankcase. I would start with that before going to the shop.

Changed one 50k ago and one 3k. Does not seem to matter.
Somewhere else lies the problem. Thanks

Run an engine vacuum test with a 0-30 in-hg automotive vacuum gauge. Look for 15-22 in-hg. Possibly a vacuum leak via the upper intake manifold. Bad UIM to LIM gasket which is not uncommon on '99 and up models.

That's where I'm heading next. With a stethascope, you can hear a slight vacuum leak around the plenum. Any trick to replacement of the gasket?
Thank you!!