All right my friends. I come here when im stumped on a problem...and this is no different :P im getting a bad squeal under the hood when I give the engine some throttle. when its at idle its just fine. I am at the end of a long process of replacing the intake manifold on my 305 85 firebird. I replaced the carb and the waterpump and both of the belts. things i have done so far to try and cure the problem: change belts again.... tighten alternator multiple times every way you can i.e. tighten the pivot bolt then the adjustment one then the pivot bolt again....ect ect...i took the fan off and ran the car with out the fan for about 1 minute. with the fan off the squeal is still there so i know the fan clutch assembly is fine. what else can it be?

 

check for a worn out alternator pulley-if belt groove is worn they will squeal even if belt is tight

 

I used a little belt dressing when I get a squeal. You need to check how loose or tight the belt is or if it is misaligned too.

 

is there any way to tell where the noise is coming from? it has to be something from the alternator, or waterpump... i took the belt off completely and turned the engine letting it run for less than a minute. with the belt off the alternator/water pump/harmonic balancer there was no noise at all! so i heard the screwdriver to the ear trick... what do you think.

 

What brand was the belt you are using? If it's a cheapo belt chances are, it'll squeal.

 

I use a 3' rubber hose to my ear to listen for noise

 

Easy way to work on stuff like that is, divide the world in half and locate the half containing the problem.

Take off the belt and run the car.

If the squeeeeeel goes away, it's an accessory.

If not, it's ... not.

At least that will tell you where to look and where not to.

If it's an accessory, manta's method is the one I use as well.