Noisier engine after service

What is your question?

I just had my timing belt, water pump, thermostat, and all the small heater hoses in the back of the engine and under the intake manifold replaced by the dealer. So now the car runs fine but is noisier, I hear a sort of howling or lower pitched whining noise. The noise itself is annoying and so far they have not been able to tell me what it is. They say it is normal engine noise but it never sounded that way before the service. I hear it at idle and when cruising around 30mph or so.