Chevrolet Repair: 1993 Chevy Suburban, chevy suburban, belt pulley

Question
When I start the truck, it makes a whistling sound.  If I rev the engine the whistling gets louder. The truck has air conditioning and the belt is rounted the correct way. I checked the belt, and it is tight, but the it sounds like the noise is coming from the belt area.  Any suggestions would be greatly appreciated.
Thanks,
Rob  

Answer
Hi Rob,
First a thought....sometimes a vacuum leak will whistle.
OK...if you can make it whistle every time, remove the belt from the tensioner, and start the vehicle, and see if the whistle went away. This will tie it to the belt driven accessories, or eliminate them.
While the belt is off, turn all the driven accessories by hand to see if you can discover anything. Wiggle pulleys and shafts for looseness also.
Then, after reinstalling the belt, take a piece of garden hose, or small vacuum cleaner hose, and holding one end to an ear to listen, carefully menuver the other end near the belt driven items.
Be very careful of the belt and fans, but this can sure get you pointed in the right direction.
Alternators often whistle, but a belt pulley out of line with the others can sound like a whistle.

Good luck,
Van