2000 BMW 535

In order to correctly assist you, I will need to know the vehicle identification number as there are two types of alternators for this body style, one of them is air cooled and the other is liquid cooled.

Mine has the water cooled one

First, this should be done on a cool engine due to the risk of scalding, as the cooling system needs to be drained. Remove the fan impeller and fan clutch with a 32MM fan wrench (left hand thread) release the tensioner bolt (pop the cover off to access the bolt head, it's a Torx T-60) and lay the tensioner roller to one side, remove the bolts retaining the alternator and remove the electrical connections, disconnect upper radiator hose to ease removal. A residual amount of coolant will be present when the alt. is removed. Also, disconnect the battery before repairs are attempted.