I did not read this whole thread so someone may have already gotten you to it.

The vacuum pump can indeed make racket that will wake the dead. Furthermore, when it is in that state, the roller can come loose, make it's way into the engine and destroy it.

It is a very quick job to pull the vacuum pump and check it. If the roller is indeed bad, I would replace the pump. A couple hundred dollars spent that will guarantee that it will not destroy the engine.

My $0.02,