Make sure all your belts are tight first.Take of all the drive belts and run the engine. If the noise gos away its not a problem with your t-belt, t-belt tensioner or water pump. Turn the engine off spin your alternator, power steering, ac compressor and ac compressor belt tensioner by hand see if thy squeal or feel ruff like a bad bearing. You can go a step further by taking only one belt off at a time and see if it gos away to help narrow it down.