N55 vaccum pump causing rattling noise?

[Kheadley]

I took my car in for a rattling noise (metallic noise at certain rpm similar to rods) and the dealer thought it was the belt tensioner, replaced that and the sound was still there and now their guessing its the vaccum pump (which is internal).

Has anyone heard of anything like this? At least they say they don't think its rod bearings.

Looking like a 3k repair job, should I just get a new engine lol considering I have 120k km.