Engine - Drive Belt Noise Diagnostics

Classification:
EM09-014

Reference:
ITB10-005

Date:
January 12, 2010

DRIVE BELT SYSTEM NOISE DIAGNOSIS

APPLIED VEHICLES:
All Infiniti

IF YOU CONFIRM

There is noise coming from the drive belt(s) or drive belt pulley(s)

ACTION

Use the flow chart in this bulletin to help diagnose and identify the source / cause of the noise.

CLAIMS INFORMATION

Refer to the current Infiniti Warranty Flat Rate Manual and use the indicated claims coding for any repairs performed.








DRIVE BELT / PULLEY NOISE DIAGNOSIS FLOW CHART





Auto Tensioner Inspection (if equipped)





1. With the engine running at idle and the AC turned ON observe the pulley angular (side to side) movement (see Example 1):

^ See above table for maximum movement specification.

^ Visual comparison of movement with a known good vehicle is recommended.





2. With the engine running at idle and the AC turned ON observe the pulley axial/lateral (back and forth) movement (see Example 2):

^ Maximum movement specification is 1 mm.

^ Visual comparison of movement with a known good vehicle is recommended.

Idler Pulley / Manual Tensioner Inspection (if equipped)





No more than 1 mm of pulley rock should be visible.

Alternator One-way Clutch Pulley Inspection





CAUTION:
Be careful not to damage the rotor.

NOTE:
The following steps can be done while the alternator is installed on the vehicle if the drive belt is removed and the alternator electrical connectors are disconnected.

1. Secure the rotor using a medium size screwdriver and a rolled shop towel.

2. Turn the pulley clockwise when viewed from the front.

^ Pulley should be locked.

^ If it rotates in both directions replace the alternator.

3. Turn the pulley counterclockwise when viewed from the front.

^ Pulley should turn with some dragging

^ If it locks or has unusual resistance replace the alternator.





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