Oh my that sounds like a vac pump. Before pulling anything else apart remove the vac pump and inspect it. They come right off, hopefully yours is still fine.

If it was the vac pump and the engine still turns over you got real lucky. That means the timing chain didn't snap so no valve job. But you are probably still going to have to pull the head to get the front cover off. All those rails will need to be inspected or replaced.

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