For 1990-2009 cars

Step | Action | Yes | No
--- | --- | --- | ---
Noise from a generator may be due to electrical or mechanical noise. Electrical noise (magnetic whine) usually varies with the ampere load placed on the generator and is a normal operating characteristic of all generators. When diagnosing a noisy generator, it is important to remember that loose or misaligned components around the generator may transmit the noise into the passenger compartment and that replacing the generator may not solve the problem.
1 | Test the generator for proper operation using an appropriate generator tester. Refer to Charging System Check . Is the generator operating properly? | Go to Step 2 | Go to Step 13
2 |

1. Start the engine. Verify that the noise can be heard.
2. Disconnect the connector from the generator.
3. Listen for the noise.

Has the noise stopped?

Go to Step 12

Go to Step 3

3 |

1. Turn OFF the engine.
2. Remove the drive belt. Refer to Drive Belt Replacement in Engine Mechanical.
3. Spin the generator pulley by hand.

Does the generator shaft spin smoothly and without any roughness or grinding noise?

Go to Step 4

Go to Step 13

4 | Inspect the generator for a loose pulley and/or pulley nut. Is the generator pulley or pulley nut loose? | Go to Step 5 | Go to Step 7
5 |

1. Remove the generator pulley.
2. Inspect the pulley and the shaft for damage or signs of overheating (due to a slipping pulley).

Is the pulley or the shaft damaged?

Go to Step 13

Go to Step 6

6 |

1. Install the pulley.

Notice: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.

2. Install the generator pulley nut.

Tighten
Tighten the generator pulley nut to 111 N·m (81 lb ft).

3. Install the drive belt. Refer to Drive Belt Replacement in Engine Mechanical.
4. Start the engine.

Has the noise decreased or stopped?

System OK

Go to Step 7

7 |

1. Loosen all of the generator mounting bolts.
2. Tighten the generator mounting bolts to specifications and in the proper sequence (if necessary). Refer to Generator Replacement .
3. Install the drive belt. Refer to Drive Belt Replacement in Engine Mechanical.
4. Start the engine.

Has the noise decreased or stopped?

System OK

Go to Step 8

8 | Inspect the generator for the following conditions:

• | Strained or stretched electrical connections (which may pull the generator and cause the generator to bind)

• | Hoses or other vehicle equipment resting on the generator (which may cause the noise to be transmitted into the passenger compartment)

Are the electrical connections pulling on the generator or are any hoses, etc. resting on the generator?

Go to Step 9

Go to Step 10

9 |

1. Reroute the electrical connections to relieve the tension.
2. Reroute the hoses, etc. away from the generator.
3. Start the engine.

Has the noise decreased or stopped?

System OK

Go to Step 10

10 | Check the drive belt for proper tension. Refer to Drive Belt Replacement in Engine Mechanical. Is the drive belt loose? | Go to Step 11 | Go to Step 12
11 |

1. Replace the drive belt tensioner. Refer to Drive Belt Tensioner Replacement in Engine Mechanical.
2. Start the engine.

Has the noise decreased or stopped?

System OK

Go to Step 12

12 | Compare the vehicle with a known good vehicle. Do both vehicles make the same noise? | System OK | Go to Step 13
13 | Important: If no definite generator problems were found, be sure that all other possible sources of objectionable noise are eliminated before replacing the generator. Replacing the generator may not change the noise level if the noise is a normal characteristic of the generator or the generator mounting.

Replace the generator. Refer to Generator Replacement .

Has the noise decreased or stopped?

System OK

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