So my alternator belt needed replacing and after I replaced it i heard an awful squealing coming from the engine. I checked to make sure that the belt was tight and someone advised putting belt dressing on the belt. But when i really got to looking, i noticed that one of the pulleys was not tuning all the time. I took a short video of it and if you all could look at it and tell me what it runs and why it may be doing that, i would be very appreciative.

 

I can't see the video at my work.
If the pulley isn't turning, then it needs to be replaced. Hopefully there is no damage to your new belt.

 

That is the compressor clutch cycling on and off, perfectly normal. As for the squealing, it could be a bearing going bad.

 

so it is supposed to let the belt run on it without it turning? Doesn't that cause the belt to heat up and break? (I am a car noob). The squealing stopped when I tightened the belt. It just kind of smells like rubber heating up now when I run the motor.

 

When you turn on the AC, the clutch engages so that the pulley spins the compressor, too. When the AC is off, the clutch is in a "neutral" mode so-to-speak.

 

@Morladim. The AC compressor has a pulley, which the main belt goes around... It spins when engine is on. As mentioned above, AC on engages the clutch and then the compressor shaft spins. Also, you mentioned "smells like rubber heating up now when I run the motor"

With engine cold and OFF, reach in and turn the "clutch" part where you see the black rubber visible. If it spins by hand your clutch may be fine. If you turn on your engine + ac, you hear a click/clanck where the clutch engages, it indicates the clutch is engaging. Then when you look under the hood while your ac is on and the black part is not spinning there, may be your compressor is frozen or is getting stuck! Stop. Turn off ac.

If you notice any rubber sprayed on to frame or hoses, there is some rubber material inside clutch and it is getting burnt. If you notice your belt is getting burned that is a worse sign. Next step is to determine if your compressor is actually frozen or just the clutch/stator is bad.

Just follow some quick diagnostic steps and post back. There are also some good videos by ETCG or Scotty Kilmer. Main thing is to avoid using the AC until you check before you cause something else to burn out as a result. You can use just the fan, but not the ac.

Edit: clicked on video, just sounds like a bad bearing in one of the pulleys

 

Take the belt off and run the car to narrow the sound down and make sure its not something under the timing cover.

 

I had an ac clutch/pulley that froze up on a Camry, burned my belt up. You can replace the AC clutch separate if you can't afford the whole compressor and don't run the Ac, but a bad compressor can also ruin a new ac clutch.