For 1990-2009 cars

Step | Action | Yes | No
--- | --- | --- | ---
DEFINITION: Noise originating from the A/C compressor, drive belt or the A/C lines.
1 | Were you sent here from Symptoms or another diagnostic table? | Go to Step 2 | Go to Symptoms - HVAC Systems - Manual
2 |

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

• | Screeching, Squealing, Chirping noises

• | Moaning noises

• | Vibration/Rattle noises

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

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

Go to Step 3

Go to Step 9

3 | With the engine OFF, inspect the drive belt for excessive wear. Refer to Drive Belt Falls Off and Excessive Wear Diagnosis for the 2.9L engine or Drive Belt Falls Off and Excessive Wear Diagnosis for the 3.7L engine. Is the drive belt excessively worn? | Go to Step 18 | Go to Step 4
4 | Inspect the drive belt tension. Refer to Drive Belt Tensioner Diagnosis for the 2.9L engine or Drive Belt Tensioner Diagnosis for the 3.7L engine. Is the drive belt tension correct? | Go to Step 5 | Go to Step 19
5 | Inspect the drive belt for excessive oil coverage. Is the drive belt covered with oil? | Go to Step 17 | Go to Step 6
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

7 | Is the A/C compressor clutch slipping? | Go to Step 23 | Go to Step 8
8 | Caution: Avoid contact with moving parts and hot surfaces while working around a running engine in order to prevent physical injury. Using a stethoscope, listen to the A/C compressor for any abnormal noises. Is the compressor causing an abnormal noise? | Go to Step 15 | Go to Step 10
9 | Does a moaning noise exist when the A/C clutch is engaged? | Go to Step 10 | Go to Step 12
10 | 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
11 |

1. Idle the engine.
2. Engage the A/C compressor clutch.
3. Using a stethoscope, move around the entire refrigerant plumbing system. Listening 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

12 | Does a vibration or rattle noise exist when the A/C clutch is engaged? | Go to Step 13 | Go to Step 14
13 | Does the noise stop when the A/C clutch is disengaged? | Go to Step 15 | Go to Step 25
14 |

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

15 | 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
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
17 | Repair the oil leak. Refer to the appropriate repair procedure for the 2.9L or 3.7L engine. Is the repair complete? | Go to Step 26 | --
18 | Replace the drive belt. Refer to Drive Belt Replacement for the 2.9L engine or Drive Belt Replacement for the 3.7L engine. Is the replacement complete? | Go to Step 26 | --
19 | Replace the drive belt tensioner. Refer to Drive Belt Tensioner Replacement for the 2.9L engine or Drive Belt Tensioner Replacement for the 3.7L engine. Is the replacement complete? | Go to Step 26 | --
20 | Repair or replace the A/C compressor mounting component. Is the repair complete? | Go to Step 26 | --
21 | Repair or replace the component which is causing the moaning concern as needed. Is the repair complete? | Go to Step 26 | --
22 | Correctly route or insulate the A/C component. Is the repair complete? | Go to Step 26 | --
23 | Replace the A/C compressor clutch. Refer to Compressor Clutch Plate/Hub Assembly Replacement . Is the repair complete? | Go to Step 26 | --
24 | Replace the A/C compressor. Refer to Air Conditioning Compressor Replacement . Is the repair complete? | Go to Step 26 | --
25 | 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 | --
26 | Operate the system in order to verify the repair. Did you find and correct the condition? | System OK | Go to Step 2