The belt could need some dressing, or the pulley could bent. The belt could need an adjustment.
Is it serious if my car idler is making a noise?
Perhaps a bad bearing in one of the belt driven components i.e. water pump,belt tensioner, alternator,idler pulley?
Pulley noise can be an indication of a component needing replacement. Pulleys contain wheel bearings which can and will wear out increasing noise. However, noise around the pulley can also mean other rotational components have a problem. Such conditions cannot be guessed and need professional-experienced mechanical diagnosis.
your car is broken
crickets
Uhh well with what you have said it could be anything, you'de need more info on what kind of noise it is, and wheres it coming from.....
It may be the Idler pulley. I used to have a 96 Breeze with a 2.0L 4cyl that made a whining noise. I thought something might be seriously wrong, but then i discovered it was just the Idler pulley making noise. I changed it-- no more noise.
wheel bearing, gearbox or wind noise Supercharger?
Its hard to say... do u know where the noise is coming from?
The A/C clutch hub is rubbing on your A/C pulley and the gap needs to be readjusted. When the A/C is off the hub free wheels with in the pulley. When the clutch energizes the hub and pulley spin together and eliminates the noise.
your car just drank red bull
you have a small cat stuck under your car