I had this squeal/whistle for about a week. I should have addressed it faster. I was driving yesterday and noticed my power steering went out. Luckily I was only a mile from home. Lifted the hood and saw the idler pulley had broken off. The bolt was sheered almost completely off. Went and got a new bolt and pulley today. It took me a minute to put on the new pulley. It took over an hour to get the belt back on. I had a lot of trouble pushing down the auto tensioner. But got it on and all is good now.