F30 crank end play

[tassie targa 76]

I know this forum is not for the F30, but I’m hoping someone can help. My sons 2013 F30 with an n20 twin turbo 245hp engine, manual had a high pitched whine, which turned out to be a pully, but after repair at the local BMW Service centre, they have told us that the crank has 1.6 mm end play, and they don’t know what could cause this, and have recommended a bottem end pull down to investigate. Has anyone ever heard of this issue, or have any thoughts. They won’t quote the work as they don’t know what the problem is. Regards Michael