There is this high toned whirring noise that.

There is this high toned whirring noise that comes from under the hood when I accelerate. This happens when it is in park or when it is moving. I opened the hood to see what I could - and I am not sure if this is the issue - but there is what appears to be a stem just to the left of the dipstick - and the top of the step looks like a nipple that would support a very small hose attached to it. I did not however - see any loose or dangling hoses that might have come off it. I have enclosed a picture. I hope that is all it is. Any help would be greatly appreciated.