I have a 2006 G6 4 cyl and I get a squeaking under the hood with the air on when first driving the car most days... sometimes no and seems like no when no ac is on. Is it the belt? it has about 57k or something more sinister? Please help, I have a GMPP but would like to avoid the dealer diagnostic and it mostly seems most issues are maintenance anyway. I recently spent $1600 in tires shocks and struts, drives awesome with a cool squeak going down the cul-de-sac.