DEFINITION: Noise originating from the A/C compressor, drive belt or the A/C lines.

Were you sent here from Symptoms or another diagnostic table?

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Go to Symptoms - HVAC Systems - Manual

1. A/C system noises can be generally categorized into 3 areas:

•	Screeching, squealing or chirping noises

•	Moaning noises

•	Vibration/rattle noises

2. Start the engine.
3. Ensure that the A/C is ON.

Is a screeching or squealing noise heard when the A/C is engaged?

Go to Step 3

Go to Step 9

With the engine OFF, inspect the drive belt for excessive wear. Refer to Drive Belt Falls Off and Excessive Wear Diagnosis for the 3.5L engine or to Drive Belt Falls Off and Excessive Wear Diagnosis for the 3.9L engine or to Drive Belt Falls Off and Excessive Wear Diagnosis for the 5.3L engine.

Is the drive belt excessively worn?

Go to Step 18

Go to Step 4

Inspect the drive belt tension. Refer to Drive Belt Tensioner Diagnosis for the 3.5L engine or to Drive Belt Tensioner Diagnosis for the 3.9L engine or to Drive Belt Tensioner Diagnosis for the 5.3L engine.

Is the drive belt tension correct?

Go to Step 5

Go to Step 19

Inspect the drive belt for excessive oil coverage.

Is the drive belt covered with oil?

Go to Step 17

Go to Step 6

1. Start the engine.
2. Ensure that the A/C is ON.
3. Inspect the compressor and the clutch.

Is the A/C compressor locked up?

Go to Step 24

Go to Step 7

Is the A/C compressor clutch slipping?

Go to Step 23

Go to Step 8

Caution: Refer to Moving Parts and Hot Surfaces Caution in the Preface section.

Using a stethoscope, listen to the A/C compressor for any abnormal noise.

Is the compressor causing an abnormal noise?

Go to Step 15

Go to Step 10

Does a moaning noise exist when the A/C clutch is engaged?

Go to Step 10

Go to Step 12

Listen to the A/C compressor components and mounting for noise concerns using a stethoscope.

Are any of these components loose, damaged or excessively worn?

Go to Step 20

Go to Step 11

1. Idle the engine.
2. Engage the A/C compressor clutch.
3. Using a stethoscope, move around the entire refrigerant plumbing system. Listen for any abnormal noises caused by a component of the A/C system touching another component.

Are any of the A/C components grounding out and causing a vibration noise?

Go to Step 22

Go to Step 13

Does a vibration or rattle noise exist when the A/C clutch is engaged?

Go to Step 13

Go to Step 14

Does the noise stop when the A/C clutch is disengaged?

Go to Step 15

Go to Step 25

1. Idle the engine in PARK with the A/C compressor clutch engaged.
2. Using a stethoscope, move around the entire A/C system testing for any abnormal noises caused by a component.

Do any of the A/C components cause an abnormal noise?

Go to Step 21

Go to Step 25

Verify that the A/C system is properly charged. Refer to Refrigerant System Capacities .

Is the A/C system properly charged?

Go to Step 26

Go to Step 16

Recharge the A/C system to specification. Refer to Refrigerant Recovery and Recharging .

Is the abnormal compressor noise still present?

Go to Step 24

Go to Step 26

Repair the oil leak.

Is the action complete?

Go to Step 26

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Replace the drive belt. Refer to Drive Belt Replacement for the 3.5L engine or to Drive Belt Replacement for the 3.9L engine or to Drive Belt Replacement - Accessory for the 5.3L engine.

Is the action complete?

Go to Step 26

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Replace the drive belt tensioner. Refer to Drive Belt Tensioner Replacement for the 3.5L engine or to Drive Belt Tensioner Replacement for the 3.9L engine or to Drive Belt Tensioner Replacement - Accessory for the 5.3L engine.

Is the action complete?

Go to Step 26

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Repair or replace the A/C compressor mounting component.

Is the action complete?

Go to Step 26

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Repair or replace the component which is causing the moaning concern as needed.

Is the action complete?

Go to Step 26

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Correctly route or insulate the A/C component.

Is the action complete?

Go to Step 26

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Replace the A/C compressor clutch. Refer to Compressor Clutch Assembly Replacement .

Is the action complete?

Go to Step 26

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Replace the A/C compressor. Refer to Air Conditioning Compressor Replacement .

Is the action complete?

Go to Step 26

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The concern may be caused by an engine related component. Refer to Vibration Analysis - Engine .

Did you find and correct the condition?

Go to Step 26

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Operate the system in order to verify the repair.

Did you find and correct the condition?

System OK

Go to Step 2