rubbin noise when heat is on

i have a 2004 mazda 3i with 77k miles on it, whenever i turn on my heat and make a left hand turn or my car dips to right i get a loud rubbing noise everytime the heat cycles on, sounds like a plastic rubbing on plastic kind of noise, and if i put it in neutral and rev the engine the sound goes faster, im thinking possible rubbing from the fan belt on the plastic cover underneath the car it is very irritating and no one seems to know the problem. again it only happens when i turn left sharp or my car is sitting leaning to the right