past coulpe of weeks i have been noticing a strange noise during startup and while running cold. popped the hood and tapped the throttle.the noise appears to be coming from the blower.definetly follows the engine speed.i recently had the blower ported and it has been working great.looking for any comments or suggestions.could this noise be the alternator going bad?

 

First disconect the blower belt to determine if its blower related,sometimes after porting u do notice more of what they call cavitation noise.Move the blower pulley with your hand to see if u feel any binding after the belt is off.If u dont feel any binding start the truck with the belt off to see if its something besides the blower.

 

Mine's been doing the same thing. I can't seem to locate exactly where the noise is coming from either. I notice it only cold, and when I put the truck in gear. When I take it out of gear, the noise seems to disappear.

 

Did u check for binding?Who ported your blower?

 

I hear that also. I think its normal with a 4lb lower

 

i am not using any aftermarket pulleys.still the stock setup.will do the binding check though.