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Makes 🢒 GMC_Truck 🢒 2006 🢒 TopKick C-Series (Conventional) C6/C7/C8 🢒 HVAC 🢒 Heating, Ventilation and Air Conditioning 🢒 Noise Diagnosis - Air Conditioning (A/C) System

Noise Diagnosis - Air Conditioning (A/C) System Sanden Compressor

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 in HVAC Systems - Manual

2
  1. A/C system noises can be generally categorized into 3 areas:
    2. • 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. Refer to the appropriate procedure:

    •  Drive Belt Excessive Wear Diagnosis in Engine Mechanical - 6.6L
    •  Drive Belt Excessive Wear Diagnosis in Engine Mechanical - 7.8L
    •  Drive Belt Excessive Wear Diagnosis in Engine Mechanical - 8.1L
    • Caterpillar® 3126 Unit Repair Manual

Is the drive belt excessively worn?

Go to Step 18

Go to Step 4

4

Inspect the drive belt tension. Refer to the appropriate procedure:

    •  Drive Belt Tensioner Diagnosis in Engine Mechanical - 6.6L
    •  Drive Belt Tensioner Diagnosis in Engine Mechanical - 8.1L
    • Caterpillar® 3126 Unit Repair Manual

Is the drive belt tension correct?

Go to Step 19

Go to Step 5

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 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 component ground-out.

Are any of the A/C components grounding out and causing a 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 14

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. Refer to Refrigerant System Capacities .

Is the A/C system properly charged?

Go to Step 24

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 25

17

Repair the oil leak.

Is the repair complete?

Go to Step 25

--

18

Replace the drive belt. Refer to the appropriate procedure:

    •  Drive Belt Replacement in Engine Mechanical - 6.6L
    •  Drive Belt Replacement in Engine Mechanical - 7.8L
    •  Drive Belt Replacement in Engine Mechanical - 8.1L
    • Caterpillar® 3126 Unit Repair Manual

Is the replacement complete?

Go to Step 25

--

19

Replace the drive belt tensioner. Refer to the appropriate procedure:

    •  Drive Belt Tensioner Replacement in Engine Mechanical - 6.6L
    •  Drive Belt Tensioner Replacement in Engine Mechanical - 8.1L
    • Caterpillar® 3126 Unit Repair Manual

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. Refer to Air Conditioning Compressor Replacement .

Is the replacement complete?

Go to Step 25

--

24

The concern may be caused by an engine related component. Refer to Vibration Analysis - Engine in Vibration, Diagnosis, and Correction.

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

Noise Diagnosis - Air Conditioning (A/C) System Delphi Compressor

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 in HVAC Systems - Manual

2
  1. A/C system noises can be generally categorized into 3 areas:
    2. • 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 the appropriate procedure:

    •  Drive Belt Excessive Wear Diagnosis in Engine Mechanical - 6.6L
    •  Drive Belt Excessive Wear Diagnosis in Engine Mechanical - 7.8L
    •  Drive Belt Excessive Wear Diagnosis in Engine Mechanical - 8.1L
    • Caterpillar® 3126 Unit Repair Manual

Is the drive belt excessively worn?

Go to Step 18

Go to Step 4

4

Inspect the drive belt tension. Refer to the appropriate procedure:

    •  Drive Belt Tensioner Diagnosis in Engine Mechanical - 6.6L
    •  Drive Belt Tensioner Diagnosis in Engine Mechanical - 8.1L
    • Caterpillar® 3126 Unit Repair Manual

Is the drive belt tension correct?

Go to Step 19

Go to Step 5

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 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

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, inspecting for any abnormal noises caused by component ground-out.

Are any of the A/C components grounding out and causing a 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 14

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 25

Go to Step 26

17

Repair the oil leak.

Is the repair complete?

Go to Step 26

--

18

Replace the drive belt. Refer to the appropriate procedure:

    •  Drive Belt Replacement in Engine Mechanical - 6.6L
    •  Drive Belt Replacement in Engine Mechanical - 7.8L
    •  Drive Belt Replacement in Engine Mechanical - 8.1L
    • Caterpillar® 3126 Unit Repair Manual

Is the replacement complete?

Go to Step 26

--

19

Replace the drive belt tensioner. Refer to the appropriate procedure:

    •  Drive Belt Tensioner Replacement in Engine Mechanical - 6.6L
    •  Drive Belt Tensioner Replacement in Engine Mechanical - 8.1L
    • Caterpillar® 3126 Unit Repair Manual

Is the replacement 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 replacement complete?

Go to Step 26

--

24

Replace the A/C compressor. Refer to Air Conditioning Compressor Replacement .

Is the replacement complete?

Go to Step 26

--

25

The concern may be caused by an engine related component. Refer to Vibration Analysis - Engine in Vibration, Diagnosis and Correction.

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