Generator Noise Test

Noise from a generator may be caused by any of the following:
- A loose drive pulley
- Loose mounting bolts
- Worn or dirty bearings
- A defective diode
- A worn stator

A high frequency whine or magnetic noise may be heard at full output. This is a normal condition.

Perform a generator output test in order to help distinguish bearing noise from magnetic noise or whine.

Refer to Generator Not Operating Properly.

A growling noise under a high load condition could indicate a shorted bridge diode. A generator with a shorted diode will also have a reduced output. Perform a generator output test. Refer to Generator Not Operating Properly.

It is also helpful to listen to the generator under a moderate load (i.e. headlights ON) in order to determine if there is a bearing or magnetic noise.


Do not disassemble the CS 1 30D generator. Generator service is limited to replacement only. Refer to Generator Replacement (2.2L) or Generator Replacement (4.3L).