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Noise from Air Conditioning

NOTE: Noise from the A/C system may be heard as squealing, chirping or moaning noises, or as a vibration noise.

  1. Start the engine and verify operation of the A/C system. If a screeching or squealing noise heard when the A/C is engaged go to step 2. If not, go to step 8.
  2. With engine OFF, inspect the drive belt for excessive wear. If the belt is excessively worn, go to step 17. If the belt is not worn, go to step 3.
  3. Inspect the drive belt tension. If the tension is correct, go to step 4. If the tension is not correct, go to step 18.
  4. Inspect the drive belt for excessive oil coverage. If the belt is covered with oil, go to step 16. If there is no oil present, go to next step.
  5. Start the engine, ensure the A/C system is ON, and visually inspect the compressor and the clutch. If the compressor does not turn, go to step 23. If the compressor and clutch are visually okay, go to step 6.
  6. Check compressor clutch for slippage, if the compressor is slipping, go to step 22. If the clutch is not slipping, go to step 7.
  7. Using a stethoscope, listen to the A/C compressor for any abnormal noise. If noise appears to be caused by the compressor, go to step 14. If the compressor is not the cause of the noise, go to step 9.
  8. Does a moaning noise exist when the A/C clutch is engaged? If yes, go to the next step. If not, go to step 11.
  9. 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? If yes, go to step 19. If no, go to the next step.
  10. Idle the engine and engage the A/C compressor clutch. 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? If yes, go to step 21. If no, go to step 12.
  11. Does a vibration or rattle noise exist when the A/C clutch is engaged? If yes, go to the next step. If no, go to step 13.
  12. Does the noise stop when the A/C clutch is disengaged? If yes, go to step 14. If no, go to step 24.
  13. Idle the engine in PARK with the A/C compressor clutch engaged. 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? If yes, go to step 20. If no, go to step 24.
  14. Verify that the A/C system is properly charged. If it is properly charged, go to step 23. If not properly charged, go to the next step.
  15. Recharge the A/C system to specification. Is the abnormal compressor noise still present? If yes, go to step 23. If no, go to step 25.
  16. Repair the oil leak. When the repair is complete, go to step 17.
  17. Replace the drive belt. When the repair is complete, go to step 25.
  18. Replace the drive belt tensioner or adjust drive belt tension. When the repair is complete, go to step 25.
  19. Repair or replace the A/C compressor mounting component. When the repair is complete, go to step 25.
  20. Repair or replace the component that is causing the moaning concern as needed. When the repair is complete, go to step 25.
  21. Correctly route or insulate the A/C component. When the repair is complete, go to step 25.
  22. Verify A/C system is not overcharged. Replace the A/C compressor clutch. When the repair is complete, go to step 25.
  23. Inspect the A/C compressor. Repair or replace as needed. When the repair is complete, go to step 25.
  24. The concern may be caused by an engine related component. If the concern is found and repaired, go to step 25.
  25. Operate the system in order to verify the repair. If the system is okay, the repair is complete. If not, repeat the entire procedure.

A/C System Flow

 

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