I'm experiencing a whining/squealing noise from the engine. It only happens after driving the vehicle around for 5 -10 minutes. I only hear it at idle, sometimes it goes away and can only be heard immediately after revving the engine. I though maybe it was a belt but it sounds like it is coming from the rear of the engine.

LS1 engine

 

Remove the oil fill cap, if the noise goes away, then it looks like the PCV fresh air hose needs to be hooked up to the 90* elbow on the throttle body.

Russ Kemp

 

Also check for loose/broken exhaust manifold/header bolts (this lets exhaust to blow past the gasket, causing a squeal sometimes, seems related to throttle, and unrelated to rpm; at other times it causes a ticking sound).

 

Intake torqued down?

 

you do not have a pcv fresh air point. you are dawing intake manifold vac on the crankcase.