Strange whine from Volvo
2006 V70 2.5t, 209000 miles. About 1 week ago, the sound started. Car drives fine, engine temp fine, power steering fluid level and color fine, mpg normal, alternator and battery check out fine, no codes thrown. The noise is definitely coming from the belt side of the engine. I’ve a feeling it’s not electrical. Sound is not present when cranking the car from cold, but starts after car has run for 5 minutes or so - or immediately if car is cranked while still warm. Sound is most evident at idle and low RPMs, but not noticeable once engine speed rises. In the beginning, it did sound like an electrical hum, but now it’s coarser and not as steady - it rises and falls somewhat at idle speed. I read somewhere this had happened to someone before, and it needed up being failing hearings in the accessory belt tensioner pulley. Just trying to get ideas before I go into the dealership. Any guesses are appreciated!