How to Replace Serpentine Belt Idler Pulley 01-05 BMW 325Xi

Difficulty: Advanced · About 90 min · Bmw 325xi

Replace the serpentine belt idler pulley, including removing the radiator fan and shroud, on a 2001-2005 BMW 325Xi.

Steps

1. Remove the radiator fan and shroud

   Disconnect the negative battery cable by loosening its 10mm nut, remove the air collector's push pin retainers and take it off, disconnect the two electrical connectors on the passenger side of the fan shroud, remove its T25 screw there and its push pin retainer on the driver side, loosen the reverse-threaded fan clutch with a fan clutch wrench, then remove the fan and shroud together.

2. Remove the old idler pulley

   Turn the A/C belt tensioner clockwise with a 16mm socket and remove that belt, release the tensioner, loosen the main serpentine tensioner with the 16mm socket, insert a pin through its holding holes, remove the belt, then remove the 16mm idler pulley bolt to free the pulley.

3. Install the new idler pulley

   Install it using its alignment tab as a guide, insert the 16mm bolt and torque it to about 30 ft-lb, refit the pulley cover if equipped, route the belt over the crank pulley, around the power steering pulley, around the tensioner, back to the water pump pulley, over the alternator and under the idler pulley (loosening the tensioner with the 16mm socket to slip it under, then pinning and releasing), then loosen the A/C tensioner, install that belt around the crank and A/C pulleys and over its tensioner pulley, and release it.

4. Install the radiator fan and shroud

   Lower the fan and shroud together, tighten the fan clutch onto the water pump pulley clockwise and torque it to about 22-29 ft-lb if possible, refit the shroud's driver-side push pin and passenger-side T25 screw, reconnect the two electrical connectors, reinsert the air collector and secure its push pins, then reconnect the negative battery cable and tighten its 10mm nut.

Check your vehicle’s repair manual for exact specifications and fit.