Concerns about my x3

[ANSx3]

I took my 2013 x3 in multiple times for engine noise.. they said It was normal. This past June my timing chain went out and blew the engine. It was replaced with a used engine in August of this year. Now it's making the same noise and running a bit rough. How concerned should I be that it'll happen again? There's about 56000 miles on it.

[crazy4trains]

You've posted a mechanical question in the detailing forum. Suggest you post your question in the appropriate model-specific forum.