My latest issue is a high pitched noise after I start the engine and it is consistent. Recently I replaced the AC compressor, tensioner assembly, and serpentine belt. Today I replaced the idler pulley just below and left of the alternator. I was planning to replace the alternator any so hoping that's it. Only other thing I can think of is the fan clutch. Doesn't sound like it's coming from the area of the PS pump or crank pulley.

 

Take the belt off and run the engine for about half a minute, see if the noise persists. If not, it's coming from something driven by the belt. If it persists, it's coming from a non-belt driven source.