Parts Catalog Accessories Catalog Tech Info Tech Forums
 
Follow Pelican Parts on Facebook Follow Pelican Parts on Twitter Follow Pelican Parts on Instagram Follow Pelican Parts on YouTube Follow Pelican Parts on Pinterest Follow Pelican Parts on Tumblr
  Search our site:    
View Recent Cars  |   Cart  | Project List | Order Status | Help    
Bookmark and Share

Pelican Technical Article:

Idler Pulley Replacement

Nick Czerula

Time:

2 hours2 hrs

Tab:

$150

Talent:

**

Tools:

Set of hex and Allen sockets, wrenches, screwdrivers

Applicable Models:

BMW 323Ci Coupe/Conv (1999-00)
BMW 323i Sedan/Wagon (1999-00)
BMW 325Ci Coupe/Conv (2001-06)
BMW 325i/xi Sedan/Wagon (2001-06)
BMW 328Ci Coupe (1999-00)
BMW 328i Sedan (1999-00)
BMW 330Ci Coupe/Conv (2001-06)
BMW 330i/xi Sedan (2001-06)

Parts Required:

Idler pulley

Hot Tip:

Work with a cool engine.

Performance Gain:

Proper engine accessory drive operation

Complementary Modification:

New drive belt
Two drive belts in E46 models with the 6-cylinder engine drive the accessories pulleys at the front of the engine. The power steering pump, coolant pump and alternator are driven by one belt and a separate belt drives the AC compressor. Each belt is routed and tensioned by the idler and tensioner pulleys.

Note that the engine-cooling fan is electric and not belt-driven.

The belts are tensioned by strong tensioners and do not need periodic adjustment. But they will, over time and due to heat, cold and the rigors of operating multiple pulleys, develop signs of wear. Signs of wear to the belts include: cracks, fraying, glazing or missing chunks. In addition, the tensioners and idler pulleys may develop defects. Bearings in these pulleys are lifetime lubricated. The lubrication eventually dries up or wears out and may cause noises. If it seizes it can damage the belt quite quickly due to excessive friction. This kind of failure can occur when you least expect it. There are a few warning signs: listen for increasing belt noise, chirping or grinding from the belt area. If you have any of these symptoms, remove your drive belts and inspect the pulleys and tensioners. Also inspect the main drive belt tensioner for straightness. As the tensioner bearing wears it can tilt, causing your drive belt to fail. 

Keep in mind that when your car was serviced before, parts may have been replaced with different size fasteners used in the replacement. The sizes of the nuts and bolts we give may be different from what you have, so be prepared with different size sockets and wrenches. 

Protect your eyes, hands and body from fluids, dust and debris while working on your vehicle. If you are working with the electrical system, disconnect the battery before beginning. Always catch fluids in appropriate containers and properly dispose of any fluid waste. Recycle parts, packaging and fluids when possible. Never work on your vehicle if you feel the task is beyond your ability. 

Our vehicle may vary slightly from yours as models do change and evolve, as they grow older. If something seems different, let us know and share your info to help other users. Do you have questions or want to add to the article? Leave a comment below. When leaving a comment, please leave your vehicle information.

In this article, I will go over the steps involved with replacing the idler pulley on the BMW E46 models with M52 and M54 engines. Be sure to work with a cool engine and remove the key from the ignition.

Most BMW E46 models utilize 2 multi-rib engine drive belts driven by the crankshaft.
Figure 1

Most BMW E46 models utilize 2 multi-rib engine drive belts driven by the crankshaft. Automatic tensioners are used to maintain belt tension and an idler pulley is used on the accessory belt to achieve proper belt wrap. The idler pulley is prone to failure, the coolant pump will lose contact with the drive belt and the engine will overheat. The pulley bearing is usually the course of the failure, creating extreme lateral play and derailing the drive belt.

.
While working at the top of radiator, remove the four expansion rivets from the intake air duct following the next step below (yellow arrows).
Figure 2

While working at the top of radiator, remove the four expansion rivets from the intake air duct following the next step below (yellow arrows).

To remove the rivets, you can use a small flathead screwdriver to pry them up, then using needle nose pliers, pull the rivet out.
Figure 3

To remove the rivets, you can use a small flathead screwdriver to pry them up, then using needle nose pliers, pull the rivet out. The expanding portion of the rivet will now come out with the duct. Depending on your model year, the vehicle may have 3 or 4 expansion rivets.

Next, remove the intake air duct from the radiator support by lifting it up and out of the intake air housing duct.
Figure 4

Next, remove the intake air duct from the radiator support by lifting it up and out of the intake air housing duct. Next, remove the radiator cooling fan shroud from the vehicle. Next, remove the alternator drive belt. Before removing drive belts, mark direction of rotation (if reusing belts) and note installation position. See our Pelican Parts Technical Article on Replacing Your Drive Belt.

While working at the top of the alternator, remove the idler puller dust cap.
Figure 5

While working at the top of the alternator, remove the idler puller dust cap.

Then loosen and remove the idler pulley bolt.
Figure 6

Then loosen and remove the idler pulley bolt.

Slide the bolt out of the alternator and remove it from your engine.
Figure 7

Slide the bolt out of the alternator and remove it from your engine. Remove the bolt from the idler pulley and set it aside, you will use it to install your new pulley.

Place the bolt through the new pulley.
Figure 8

Place the bolt through the new pulley. Install the new pulley through the alternator and fasten it to your engine. Check that idler puller alignment tab is properly aligned with the notch in alternator. Torque the bolt according to your vehicle's specs. Next, reinstall drive belts. Start your engine and check that the belt and pulleys are aligned properly.

Bookmark and Share
Comments and Suggestions:
Bob@RDU Comments: My 99 323ic does not have 'idler pulley'. Are you sure all models have 6 pulleys vs 5?
August 30, 2015
  Followup from the Pelican Staff: US models have the idler pulley. - Nick at Pelican Parts  
Mel279 Comments: I have just replace all the pulleys, tensioners and belting, why is it the alternator belt look slacken? the idler pulley is recently replaced.
October 20, 2014
  Followup from the Pelican Staff: Maybe you installed a belt that is too long? That is if the tensioner is working correctly. - Nick at Pelican Parts  
Max parker Comments: Thanks,
December 16, 2013
  Followup from the Pelican Staff: Glad to help. - Nick at Pelican Parts  
Max parker Comments: Do i have to take the radiator off ? Somepeaple say you do some dont
December 14, 2013
  Followup from the Pelican Staff: No, just remove the cooling fan shroud. - Nick at Pelican Parts  

  Search our site:    

View Cart & CheckOut | Project List | Order Status |  Help    

 

[Home] [Customer Service] [Shopping Cart] [Privacy Statement]
 [Contact Us] [About Us] [Shipping] [Map to our Location] [Careers]

Copyright © Pelican Parts Inc.

Page last updated: Mon 12/5/2016 02:18:39 AM