ive done some searching and have came up with it either being the a/c clutch, belt pulley or something else. the car makes a rattling type noise that comes and goes every few seconds. when you turn the heat on it seems to get worse and same with the a/c. the a/c blows ice cold but the heat isnt that hot. when you turn it off it tends to get a little quiter. also for some reason when the car is in drive it gets louder but in park or neutral it does go away but not completely although that may be sometyhing else. you can hear it pretty good from the driver seat and it seems if you give it more gas when driving sometimes it gets louder but if you let off for a second it will go away. any help is really appreciated.