Originally Posted by watt4
great post. I have been having this issue too, and have been researching the cause. At first it was more of a whistle, now sounds more like metal on metal rattle, kind of like a bearing. I'm thinking alternator. thanks
I keep the longest screw driver in my box ( actually more if a gasket scraper) just to listen to accessories and pans/covers. One end plugged to my ear, the other probing various assemblies. Found many strange noise sources with just that. Once you zero in on the source of metal / metal rub, you will know it.
A mechanics stethoscope is invaluable too for the ~$5 it will cost. Solid tip probes solid noises, hollow probe finds air noises.
Neither for the feint of heart or long of hair.