Noise Diagnosis - Air Conditioning (A/C) System
Noise Diagnosis - Air Conditioning (A/C) System
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DEFINITION: Noise originating from the air conditioning compressor, drive belt or the air conditioning lines. |
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1 |
Were you sent here from Symptoms or another diagnostic table? |
Go to Step 2 |
Go to Symptoms - HVAC Systems - Automatic |
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1. Air conditioning system noises can be generally categorized into three areas: Screeching, squealing, chirping noises Moaning noises Vibration/rattle noises 2. Start the engine. 3. Turn the air conditioning ON. Is a screeching, squealing noise heard when the air conditioning is engaged? |
Go to Step 3 |
Go to Step 9 |
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3 |
With the engine OFF, inspect the drive belt for excessive wear. For LM2 engine, refer to Drive Belt Falls Off and Excessive Wear Diagnosis For L82, L84, and L87 engine, refer to Drive Belt Falls Off and Excessive Wear Diagnosis Is the drive belt excessively worn? |
Go to Step 19 |
Go to Step 4 |
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Is the vehicle equipped with a drive belt tensioner? |
Go to Step 5 |
Go to Step 6 |
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Inspect the drive belt tension. Drive Belt Tensioner Diagnosis Is the drive belt tension correct? |
Go to Step 6 |
Go to Step 20 |
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Inspect the drive belt for being oil soaked. Is the drive belt soaked with oil? |
Go to Step 18 |
Go to Step 7 |
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1. Start the engine. 2. Turn the air conditioning ON. 3. Inspect the air conditioning compressor and |
Go to Step 25 |
Go to Step 8 |
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No |
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Is the air conditioning compressor locked up? |
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Is the air conditioning compressor clutch slipping? |
Go to Step 24 |
Go to Step 9 |
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Warning: Refer to Moving Parts and Hot Surfaces Warning. Using a stethoscope, listen to the air conditioning compressor for any abnormal noises. Is the air conditioning compressor generating an abnormal noise? |
Go to Step 16 |
Go to Step 11 |
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Does a moaning noise exist when the air conditioning clutch is engaged? |
Go to Step 11 |
Go to Step 13 |
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Using a stethoscope listen to the air conditioning compressor components and mounting for generating noise. Are any of these components loose, damaged or excessively worn? |
Go to Step 21 |
Go to Step 12 |
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1. Engine at idle. 2. Engage the air conditioning compressor clutch. 3. Using a stethoscope, move around the entire refrigerant plumbing system, inspecting for any abnormal noises caused by a component ground-out. Are any of the air conditioning components grounding out and generating a noise? |
Go to Step 23 |
Go to Step 14 |
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13 |
Does a vibration or rattle noise exist when the air conditioning clutch is engaged? |
Go to Step 14 |
Go to Step 15 |
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Does the noise stop when the air conditioning clutch is disengaged? |
Go to Step 16 |
Go to Step 26 |
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1. Transmission in the PARK position. 2. Engine at idle. 3. Air conditioning compressor clutch engaged. 4. Using a stethoscope, move around the entire air conditioning system testing for any abnormal noises caused by a air conditioning component. Do any of the air conditioning components generate an abnormal noise? |
Go to Step 22 |
Go to Step 26 |
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Verify that the air conditioning system is properly charged. Approximate Fluid Capacities |
Go to Step 27 |
Go to Step 17 |
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Is the air conditioning system properly charged? |
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Recharge the air conditioning system to specification. Refrigerant Recovery and Recharging Is the abnormal air conditioning compressor noise still present? |
Go to Step 25 |
Go to Step 27 |
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Repair the oil leak. For LM2 engine, refer to Oil Leak Diagnosis For L82, L84, and L87 engine, refer to Oil Leak Diagnosis Is the repair complete? |
Go to Step 19 |
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| 19 |
Replace the drive belt. For LM2 engine, refer to Accessory Drive Primary Belt Replacement For L84, and L87 engine, refer to Accessory Drive Primary Belt Replacement For L84, and L87 engine, refer to Accessory Drive Auxiliary Belt Replacement Is the replacement complete? |
Go to Step 27 |
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Replace the drive belt tensioner. For LM2 engine, refer to Drive Belt Tensioner Replacement For LM2 engine, refer to Generator and Drive Belt Tensioner Bracket Replacement Is the replacement complete? |
Go to Step 27 |
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| 21 |
Repair or replace the air conditioning compressor mounting component. Is the repair complete? |
Go to Step 27 |
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| 22 |
Repair or replace the component which is causing the moaning concern as needed. Is the repair complete? |
Go to Step 27 |
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| 23 |
Correctly route or insulate the air conditioning component. Is the repair complete? |
Go to Step 27 |
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| 24 |
Replace the air conditioning compressor clutch. Air Conditioning Clutch Replacement Is the repair complete? |
Go to Step 27 |
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Action |
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| 25 |
Replace the air conditioning compressor. Air Conditioning Compressor Replacement Is the repair complete? |
Go to Step 27 |
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| 26 |
The concern may be caused by an engine related component. Vibration Analysis - Engine Did you find and correct the condition? |
Go to Step 27 |
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| 27 |
Operate the system in order to verify the repair. Did you find and correct the condition? |
System OK |
Go to Step 2 |