Black smoke and loud banging from engine is my x5 dead?

[wpoll]

Where was the black smoke coming from? Tail pipes or under the bonnet (hood)?

If the smoke came from under the bonnet, then jdd is probably on the money - the harmonic balancer (the large composite pulley on the front of the crankshaft, that drives the v-belts) has probably failed. A few other folk here have had a similar failure with similar symptoms.