Start with an inspection at a tire and alignment shop if they didn't do one already when they put the tires on. Noisy wheel bearings are becoming common on all brands of vehicles but typically once they start making noise, they do so all the time. They will sound like an airplane engine.
Ford has had more than their share of ball joint problems so those should be inspected very closely. They don't make grinding noises though; they might make an audible clunking noise but often you can't even hear them.
Another way to locate noises is with a "Chassis Ear". That is a set of six microphones, a switch box, and headphones. You clip the microphones to suspect points then drive while switching between the microphones and listening with the head phones. By moving the microphones around, you can zero in on the source of the noise. Be aware that many mechanics have never heard of or seen one of these tools. You might find one at an auto parts store that borrows or rents tools.
Sometimes the splash shield behind one of the front brake rotors gets bent and rubs on the rotor. The speeds you mentioned shouldn't be a factor but don't overlook them. They can be easily bent away from the rotor by hand.
May 24, 2011 at 12:47 AM
