how to remove and install serpentine beltfor the alt,p/s pump,
serpentine belt specs on 2003 BMW 325i
I suggest getting a repair manual from Bentley: http://bit.ly/Bentley_Repair_Manuals
1 more answer
there is an idler or tension pulley above the alternator but closer to the water pump pulley, feel just below the top belt and you will feel a casting for a 17mm socket head. I had to use a cheater bar on the end of my ratchet....here is something very helpful if you look at the tension housing you will see two castings that appear as though a small bolt would fit through if they were lined up and that is correct this allows you to release tension on your ratchet and change out the belt.