It doesn't sound like a vacuum leak to me. It sounds more like either a wheel bearing issue or uneven tire wear.
Ask her to do this. In an area where it is safe (no traffic), drive the car until she hears the noise. Then, turn the steering back and forth from left to right. Does the sound change? If it does, in which direction does it get louder?
Also, have her check to make sure the tires are not cupped or worn unevenly.
Let me know what you find,
Monday, August 18th, 2014 AT 6:47 PM