When I turn on HVAC it makes growling noise. If I engage clutch and drop RPM'S it gets quiet. And when I turn off A/C noise goes away. Any ideas? Thanks

 

Belt-Crank Pulley-Idler Pulley, or the AC compressor.

 

For me a growl around the motor is a bearing going and since it coincides with the AC then I would think AC Compressor.

 

My money is on the crank pulley or the belt tensioner. Who is the bookie taking the bets?

 

I have an R50 and it does the same thing. My bet is a/c compressor. I have "fixed" this with a louder exhaust and a turn of the volume **** to the right. Noise seems to go away though it does come back between songs... any ideas?

 

+1 for A/C Compressor. The same scenario preceded by compressor disintegrating and taking out the condenser in the process. Very expensive repair, BTW. I kind of deserved it for ignoring for 6 months... in the heat... of Albuquerque. :(