Hi,Does anyone know why my car makes a howling sound?

A wheel or hub bearing increases with vehicle speed. Same goes for tires that are cupped.
Drive on the crown of the road. Now switch to left lane. Now to right lane.
Which made the howling more pronounced?

A wheel or hub bearing increases with vehicle speed. Same goes for tires that are cupped.
Drive on the crown of the road. Now switch to left lane. Now to right lane.
Which made the howling more pronounced?
It also howls when idling,sounds like it is coming from under the hood..

Waterpump?

It could be the A/C compressor bearing, the idler pulley, or the water pump like kitch said. Take off the belt, start the vehicle and see if the noise continues. Check pulleys for any side-to-side play; they should all be bolted on tight. If they move, it's because the bearing is worn out.