2002Impala

I have a 2002 Impala LS with the 3.8 k vin engine 70000 Miles. Everything was running great till a few days ago. Now i have a loud squeal on start up and shut down and a quieter squeal while idling. If you pull the dip stick or slightly lift up the oil cap the sound goes away. I have been searching Threads for 3 hours now. I have changed the PVC valve and made sure the 2 orings were in good shape and not cut or deformed. Its not a pulley or water pump(ran it momentarily without a belt and replaced the water pump today). Took out the pcv valve and covered the intake port with my finger. Had a friend start the car. NO squeal! Pulled the oil cap still plenty of vacuum to be had. Thats how I came up with the excessive vacuum. Where else could vacuum come from since the PCV valve system has been bypassed. Thanks for the help. Tyler

P.S. Bought the car a week ago go figure.

HotSauce6226

Take it to a dealer and see what the deal is, since your only had it in that short time