N14 Rattle front drive

I had my fan hub rebuilt....Mine recently makes a clacking noise and its loud....the tech said its the play in fan so if its the splines how do I fix that issue...,..Should it of been fixed with rebuilt hub

 

You don't have to time the Air compressor on a NT engine.

 

Could be timing train rattle they are straight cut on those I think they made a special gear/idler on the newer ones that had springs in it and took up the lash kinda wonky but it worked

 

It could be just gear rattle from gear lash or clearance between the gear teeth.
I think its pretty normal for the most part. The vibration damper on the front of the crankshaft may be contributing as well. The damper has a steel ring in it and the damper is filled with a silicone fluid.
Over time the silicone hardens and the damper no longer dampens. To determine if it has reached the end of its life remove it and carefully clean the paint off it and measure the thickness. it should be within .010" all the way around. If its more than .010" it needs to be replaced.