Most likely cause is the belt, tensioner, or driven component. As a test, remove the belt and see if the noise goes away......it won't hurt to run like this for a short time. If no noise, you at least know it is in this area - not the engine itself.i have a 96 lT1 caprice...and when i start it .....there is a ssqueeking noise....when i drive it for about ten to 15 min. it goes away....and stays away...wat could this be????