Whinning noise @ serpentine belt area. on 2008 Volkswagen Jetta

Notice a whinning noise coming from the serpentine belt location. Noise mostly during idle & acceleration. Was told by a friend that owns the same year Jetta, who also had the same problem, said that the Idler pulleys (upper / lower) & both tensioner pulleys where going bad. I went ahead & changed out the pulleys & serpentine belt but still getting the whinning noise. Any suggestions of what might be causing the noise?

Jason

Asked by for the 2008 Volkswagen Jetta
My guess would be belt tensioner needs replacing,or waterpump is going bad.