I thought it was the belt squeeking so I bought a "gator back" belt but when I was installing it I noticed the alternater pully was squeeking when I spun it. I didn't have another alt so I grabbed some Seafoam "Deep Creep" spray and hit the front and rear of it. The squeek went away immediately and hasn't come back.

Do you think it will be fixed for a while?

 

Until it comes back! LOL

Light penetrating oil probably will not fix it for good.

 

I'd have to agree with swartlkk. I have seen some noisy alternaters last for a long time but generally once they start squeeling they don't last long after.