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Home >> Hummer >> 2008 >> H2 4D Utility Wagon >> Repair and Diagnosis >> Heating, Ventilation & A/C (HVAC) >> HVAC Control Systems >> Heating, Ventilation, And Air Conditioning >> Diagnostic Information and Procedures >> Noise Diagnosis - Air Conditioning (A/C) System

Noise Diagnosis - Air Conditioning (A/C) System

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 - Automatic
2
  1. A/C system noises can be generally categorized into 3 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 .
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 .
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: Refer to Moving Parts and Hot Surfaces Caution .
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 Crankcase Ventilation System Inspection/Diagnosis for the 6.2L engine.
Is the repair complete?		 Go to Step 26  -
18 Replace the A/C drive belt. Refer to Air Conditioning Compressor Belt Replacement .
Is the repair complete?		 Go to Step 26  -
19 Replace the A/C drive belt tensioner. Refer to Drive Belt Tensioner Replacement - Air Conditioning .
Is the repair 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 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 
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