Q: My 2008 Volvo xc 90 makes a whistle like sound

Hi J.M. Thanks for contacting us tonight. It really depends when the whistle noise occurs that might indicate the source and cause of the noise. If the noise is frequent when the vehicle is in motion, this could be coming from the wheel bearings - or even a CV joint that is slowly wearing out. If the noise happens as soon as you start the motor, then a loose or wearing out serpentine belt - or drive pulley is likely the source. AC components can also cause a high pitched whining noise. I think the best thing to do is try to isolate the time periods when these noises occur or particular situations. You can also have one of our mobile mechanics come to your location to complete an onsite inspection to see if they can isolate the source of this noise and recommend the right repairs.