Do it yourself
Frequently asked questions about cars and motorcycles
Car tutorial (Do it yourself) Motorcycle tutorial (Do it yourself) Frequently Asked Questions

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

Video tutorial

Related tutorials

Alternator Replacement Instructions
BMW Serie 5 (1995-2003 / E39) To replace the alternator, first disconnect the battery. Then, remove the engine air filter box (AIR BOX) to access the alternator. Next, loosen the …
Replacing the Auxiliary Belt Tensioner Pulley
Replacing the Auxiliary Belt Tensioner Pulley
BMW Serie 5 (1995-2003 / E39) The auxiliary belt tensioner pulley is the plastic one located roughly in the center of the pulley cascade. Before proceeding with the removal, it is…
Battery Replacement Without Losing Codes
Battery Replacement Without Losing Codes
BMW Serie 5 (2003-2010 / E60, E61) Many electronic systems in the vehicle can lose some settings if the battery is disconnected, from the simple clock to the radio unlock code. There i…

Other guides you may be interested in

How to Remove the Diesel Filter from a Peugeot 207

Lift the bonnet; remove the soundproofing panel from the engine and locate the diesel filter (as shown in the video). Using a socket wrench, unscrew the bolts (a spanner can also be used) near the container where the diesel filter is located. Once the filter is removed, disconnect the circulation hoses and take it out of the vehicle (replace it with a new filter). Finally, refit the filter to the attached container of the diesel filter (connect the hoses and wires) and tighten the appropriate bolts. Close the bonnet afterwards.

Watch the video!


by ScegliAuto

More videos