E46 rattling noise during idle, coming from front of engine

Rattling noise is coming from front of engine will idling on cold. Seems to go away a bit when engine is warmer.

[bigslappy]

im assuming the issue is the diso valve flap rattling on idle. it'll go away when gas is given due to the flap opening all the way. My issue was the diso not holding the flap. You can test the diso valve flap by taking it out, manually shutting the valve and holding a hole shut. If the flap doesn't stay closed, its probably the flap making the noise.