What could be the problem if there's a whining noise in the engine? on 2005 Chevrolet Trailblazer

Loud whining noise in the trailblazer,any ideas on what that could be??

Asked by for the 2005 Chevrolet Trailblazer
wish I could help, we have a 2008 trailblazer with the same problem, everytime we start it up it sounds like a jet engine taking off, then it winds down.