My girlfriend has a 1992 Blazer, 2 door, fuel injected w/ a 350 - not the original motor in the car, her father replaced it about 30K miles ago from a junker. The car doesnt run hot, the ps pump is *not* weeping but the engine makes a chirp sound (kind of like a bad pulley). Looked at the belts and there isnt any excessive wear. The noise comes on right around the time the engine starts to come off "choke", makes noise at idle and doesnt exactly get louder when theres more rpm and/or load on the motor. When engine speed increases the noises "rpm" also increases. It leads me to believe its directly related to a moving part. It's been adjusted a few times but then it just comes back after about a week or 2 of regular use. I seem to think the pulleys aren't properly aligned and its killing the ball bearings...am I onto the issue?

 

look for signs of build-up on the pulleys and if there's rust or black debris (rubber) clean it off with light grit emery cloth and restart engine if that doesn't help then try replacing the idler pulley or the tensioner hope this helps

 

It turned out my water pump pulley was actually worn. (Over 200,000 miles). The back of the serpentine belt drives it. There were actually ridges on the water pump pulley that prevented the belt from riding on the pulley correctly. I replaced the pulley and the problem was corrected. Not saying this is the problem, but after replacing the tensoner and belt, cleaning the grooves in the pulleys and checking alignment, i finally stumbled in this solution. good luck!