Q: Propeller sound from under the car but only when driving in a straight line.

Hi There, What you are describing sounds like possibly a failing wheel bearing. A wheel bearing will usually fail due to pitting or small damage on the surface of the rollers or the bearing race. Over time the bearing will wear slightly, allowing microscopic pieces of metal into the grease. These microscopic pieces of metal, as well as any contamination that gets into the bearing, will wear away at the highly polished surfaces causing pitting and deformation. Since so much weight is riding on your wheel bearings, and so much load is put on them in corners, even the smallest amount of surface damage to your bearing can cause a lot of noise, which may fluctuate depending on which wheel bearing is damaged and to what degree. I would suggest having an expert from YourMechanic come to your location to diagnose and inspect your vehicle.

Hi there. Typically a clicking sound that increases in speed in conjunction to the momentum of the vehicle will come from the wheel or drive line. In some cases the noise is due to a brake rotor that is warped, and is clicking against the brake caliper. It can also be due to a wheel bearing that is damaged, CV joint that is damaged or even the inside of the wheel that has a wheel weight that is clicking on the brake caliper. The best way to diagnose this problem is to have a professional mechanic come to your location and complete a car is making a noise inspection.