GM Service Manual Online
For 1990-2009 cars only

The following conditions may cause the generator to emit noise:

    • Insufficient fan clearance to bolts or structures
    • Dirty or worn bearings
    • A worn diode or stator

If the pulley and mounting bolts are snug and the noise continues, remove the generator for inspection and repair. Refer to Generator Replacement .

A loose drive pulley or loose generator mounting bolts may also cause a generator to emit noise. In some cases, the generator has been relocated in order to mount aftermarket equipment. Inspect the generator brackets for structural failure or misaligned pulleys. Observe the generator with the engine running in order to ensure that the following conditions do not exist:

    • Excessive vibration
    • Excessive motion
    • Squealing or other abnormal noises