High Pitch Squeal From Engine 3.2

[JCB986]

I replaced my serpentine belt back a few months ago and I started getting a low pitch chirp that now has tun into a high pitch squeal. I disconnected the belt and started the engine because the squeal was hard to pin point. With the belt off and the engine running I have the squeal. Now, it only starts after the engine has run for more than 20 minutes and it has reached operating temperature. The odd thing is when you race the engine up the squeal will disappear and even quit. Slowly returning as a chirp, quickly into a squeal. Any thoughts.

[JCB986]

I posted the above message, but in the mean time I decided to check the AOS. I discovered it was going bad. Have not gotten any codes thrown or smoke associated with a failure, just that annoying squealing which actually is pressure building up the crankcase and being forced out through the front crank seal. Also, the oil filler cap could not be removed while engine was running, another sign of the AOS going bad.