The VANOS pressurized with oil within a few seconds. VANOS rattles go away very shortly after start up. I'd be worried about the oil pump and especially the oil pump sprocket. I think there is a service bulletin on how to check it. Did you do the work yourself? Did you check the tension on the small chain that drives the oil pump?

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David.X5
2001 X5 4.4i Sport
SOLD! at 160k miles