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Replace Idler Pulley

Model: BMW Serie 5 E39 - Years 1995-2003
Part: V-belt

To replace the idler pulley of the auxiliary belt (the small plastic one located at the top, mounted directly on the alternator), you first need to remove the plastic cover of the radiator-fan assembly and the fan itself (for which you need a specific wrench).
Before removing the auxiliary belt, it is suggested to sketch the routing on the various pulleys to avoid making mistakes during reassembly. Then, loosen the tensioner and slide the belt off the pulleys; next, remove the mounting pin of the idler pulley and replace it with the new one, ensuring the alignment of the centering pin behind the pulley with its respective seat. Finally, reposition the belt (consider replacing it if it shows cracks or wear) and reassemble everything that was previously removed.

Updated on 10 February 2026 by ScegliAuto

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