Alternator decoupler pulley should spin freely?
 

Hello all

Trying to understand more and diagnose failing bearing sound.

For the decoupler pulley of the alternator, if I understand correctly, the pulley should spin freely on one side, not turning the inside parts of the alternator, but be engage when spining the other side, right?

Cause mine is engage both sides. I more and more think it's the alternator bearing or pulley causing my strange noise.

Thanks
Chris

this is not a direct answer to your question, but depending on the model year and maybe auto/manual, the 986 parts catalog calls out pulley with free wheeling and pulley without.
you did not specify which year and model type.
I have 01 box base with 5 speed. it has free wheeling pulley. with pulley cap. need special tool to remove the pulley.

I know it's a free pulley. Its easy to see the difference. I have a 2000 S manual.

later
Chris

Your diagnostics sounds about right......
My free wheel pulley also siezed a couple of years ago, but it sounded more like a rumbling sound @ idle.
As a side note, you don't need to remove the alternator to remove the pulley - as long as you have the special removal tool, which saves a lot of time & hassle.

Just remember: while holding the spline tool stationary, turn the inner tool CLOCKWISE to remove the pulley. (you'll know what this means when you get to it)