It could very well be your A/C belt loose or compressor seizing up. Especially if it does it when turn defrost on, because on that model the a/c comes on when you select defrost also, it clears windsheild quicker. Sray your a/c belt w/W.D.40, or belt dressing, see if noise goes away. If it does, maybe just need to tight'n belt. You can also spray W.D, or any penetrating oil on compressor fins on outside of pulley, never hurts to give it some lube & it quiets comp. Some too. If you think you have comp. Prob., Take off a/c belt, see if pulley turns. GOOD LUCK !
P.S., Also ck. All idler pulleys for seize'n up & yes, make sure alt. Job correct. Why they do it twice?
Saturday, June 27th, 2009 AT 1:32 AM