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Home >> Chevrolet >> 2020 >> Express 2500 LS, 6.0L Eng VIN G >> Repair and Diagnosis >> External Pages >> Different car >> Section 55 (Heating, Ventilation, And Air Conditioning System) >> Diagnostic Information and Procedures >> Noise Diagnosis - Air Conditioning (A/C) System (LWN)

Noise Diagnosis - Air Conditioning (A/C) System (LWN)

WARNING: This page is about a different car, the 2019 GMC Savana 3500, 2019 GMC Savana 2500, 2019 Chevrolet Express 3500, and 2019 Chevrolet Express 2500. However, it is still accessible from the selected car via links, so may be relevant.
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.
Do you hear a screeching, squealing noise when you engage the A/C?		 Go to Step 3  Go to Step 9 
3 With the engine OFF, inspect the drive belt for excessive wear. 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. 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 23  Go to Step 7 
7 Is the A/C compressor clutch slipping? Go to Step 23  Go to Step 8 
8 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. Start 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 24 
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 listening 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 24 
15 Verify that the A/C system is properly charged. Approximate Fluid Capacities 
Is the A/C system properly charged?		 Go to Step 24  Go to Step 16 
16 Recharge the A/C system to specification. Refrigerant Recovery and Recharging 
Is the abnormal compressor noise still present?		 Go to Step 23  Go to Step 25 
17 Repair the oil leak. Oil Leak Diagnosis
Is the repair complete?		 Go to Step 25  -
18 Replace the drive belt. Drive Belt Replacement
Is the replacement complete?		 Go to Step 25  -
19 Replace the drive belt tensioner. Drive Belt Tensioner Diagnosis
Is the replacement complete?		 Go to Step 25  -
20 Repair or replace the A/C compressor mounting component.
Is the repair complete?		 Go to Step 25  -
21 Repair or replace the component which is causing the moaning concern as needed.
Is the repair complete?		 Go to Step 25  -
22 Correctly route or insulate the A/C component.
Is the repair complete?		 Go to Step 25  -
23 Replace the A/C compressor. Air Conditioning Compressor Replacement (LWN) , or Air Conditioning Compressor Replacement (LV1) , or Air Conditioning Compressor Replacement (L96, LC8) 
Is the replacement complete?		 Go to Step 25  -
24 The concern may be caused by an engine related component. Vibration Analysis - Engine
Did you find and correct the condition?		 Go to Step 25  -
25 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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