Sounds like you found your problem!

It’* been determined this noise is coming from inside the engine. What would cause a chattering type noise that seems to be somewhere near the front of the engine. Basically only do it at idle and when in gear. And if you remove the belt the noise is gone.

I’m guessing the belt tension on the crank pulley is causing the noise.

a scope put on seemed to be loudest of the oil filter. There was a small amount of metal tiny shaving when I drained the oil recently. This was after changing oil filter 1000 miles ago. I was told that’* normal

With the belt off the noise is gone. That tells us it'* in one of the rotating devises. A stethoscope will find it.

every pulley was replaced but the ps. And it’* rock solid. The scope was loudest at the oil filter.

Did you do this?

Did you replace the water pump?

Mystery language. Who did the determining and how did they do it?

Probably an accessory.

Based on this, even more likely it is an accessory.

The crank pulley itself wouldn't make this noise unless the harmonic balancer is coming apart inside. This is just about unheard of on this engine. If it is eating bearings, you'd hear deep knocking, especially at warm startup.

Metal shavings are not normal for this engine.

It make little to no noise until it warms up. Maybe 5 minutes or a bit less. Then u start to hear a light chattering and continues to get louder for the next few minutes

Every pulley has been tested with a new pulley. WP AC ALT. The tensioner assembly with a used one and a used pulley on tensioner from my other Buick. I took off the crank HB pulley. Rubber looked like new inside.

could there be anything inside by the oil pump causing this? Someone suggested the spring could. Seems unlikely to me.

Record the noise.

I agree, we need to hear it.

it’* always a bitch to upload iPhone videos. It just won’t. This jackhammer is almost exactly the same sound.