alternator spinning hissing sound

[M11's]

my alternator has a slight hssing sound when the pulley is spinning. what could be causing it, how to fix it. the alternator is fine condition.

[Ceepo]

Hissing? or a Squeling?

If its squeling tighten the belt, how tight is the belt, maybe it is to tight...

[Bigsyke]

Metal debris can get into the alternator and cause this. I had to modify my Quest alternator to fit and some of the metal shavings got in, and it caused this until it worked its way out.

However my ka24de alternator started making a whining sound when it was failing. It will test fine at autozone, but if you have the radio, fans, headlamps and heater on it would pull 11.6xv. Do a load test.

[M11's]

Belt is at a good tension. How do you test alt. I have a volt meter. I have no radio, only one electric fan so it has a small load on it. At most headlamps and heater at two. Outside of alt. does look dirty so squealing could just be debris?