Anong klaseng ingay po ba yung naririnig nyo? Squeaking sound ba? Kung ganun baka sliding belt lang.

Try this din, kung nasa shop ka, patanggal mo yung belt ng A/C then start the engine. Kung wala na yung sound, most probably sa A/C system nga ang problem pero kung nandun padin, you might want to check na yung bearing ng alternator. and any other moving parts while the engine is idling (minor).

HTH.

P.S. I'm glad I was able to help sa pag post mo ng new thread. Welcome din sa tsikot.