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Whine Moan Or Rattle Noise Only When A/C Is On - keywords air bolt bracket compressor contact dash hose HVAC IP knock line loose moan noise rattle refrigerant steering whine

Subject: Whine Moan or Rattle Noise Only When A/C Is On

Models:2008 Buick Enclave
2007 GMC Acadia
2007 Saturn Outlook



The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.

Condition/Concern:

A rattle, moan, or whine noise may be noticed when the A/C Compressor is engaged while running at higher engine RPM, usually around 2000 to 3000 RPM. The noise will stop immediately when the compressor is disengaged. Do not replace the compressor or TXV (Thermal Expansion Valve) for this noise.

Recommendation/Instructions:

There are two possible causes for the noise.

* Inspect for loose or missing A/C Compressor Bracket bolts and repair as needed. There are 4 bolts that retain this bracket to the engine, Three bolts are located on the front of the engine and one bolt is located behind the compressor on the side of the engine. The compressor will have to be removed from the Compressor Bracket to access the bolt on the side of the engine. The compressor can be removed from it's bracket without having to remove A/C lines or recover refrigerant from the system. See picture below


Object Number: 1990585  Size: SH

* Inspect for contact or smaller than desired gaps between the Power Steering Hose and the A/C refrigerant hoses. Adjust the position of the Power Steering hose to prevent contact. See picture below


Object Number: 1990588  Size: SH
  1. A/C refrigerant hoses on back side of engine
  2. Power Steering Hose on back side of engine

Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.