Could be anything from a vibrating heat shield to a bad bearing on an accessory. If you listen through a rubber hose and aim it all around, you should be able to locate the noise source as the hose points at it.

Hi,

I recommend taking your Fusion to your local Ford Dealer to be diagnosed. Our certified technicians will be glad to take a look, and answer any inquiries.

Locate a dealer near you, and set up an appointment with the link below:

http://owner.ford.com/servlet/ContentSer...

Enjoy the rest of your day!

Tricia

Sounds like a belt, but it could be other things. I'd check those first. Everything else is going to be much more expensive.

Someone has to look under the hood while you run the engine and make the sound.

Check your belts and make sure everything moves freely and that nothing is leaking any type of fluid.

I have a 2008 Ford Fusion SE 4 Cylinder with 78,000 miles on it. When I accelerate I hear a humming noise coming from the front. The higher the RPM's the louder it gets. The sound begins after 1000 RPM's. I sat it and parked it and put my foot on the gas pedal and went up to 4,000 RPMS and it sounded like a siren you would hear in the movies for like code red or something I don't know. I have no idea what it may be. Answers would be very much appropriated. Thanks!