Chevrolet Silverado / GMC Sierra. Service manual — part 2309

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

Verify that the A/C system is properly charged.

2008 Chevrolet Silverado 1500

2008 HVAC Heating, Ventilation, and Air Conditioning - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra &

Silverado

15

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. Refer to the appropriate
repair procedure in Engine Mechanical.
Is the repair complete?

Go to Step 26

-

18

Replace the A/C drive belt. Refer to Air
Conditioning Compressor Belt
Replacement .
Is the replacement complete?

Go to Step 26

-

19

Replace the A/C drive belt tensioner. Refer to
Drive Belt Tensioner Replacement - Air
Conditioning .
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 (4.3L, 6.6L) or Compressor
Clutch Plate/Hub Assembly Replacement
(V8 - Gas).
Is the replacement complete?

Go to Step 26

-

24

Replace the A/C compressor. Refer to Air
Conditioning Compressor Replacement
(LY2, LY5, LH6, L76, L92 and LMG) or

Air

Conditioning Compressor Replacement
(LLY/LMM)

or Air Conditioning

Compressor Replacement (LU3).
Is the replacement complete?

Go to Step 26

-

The concern may be caused by an engine related

2008 Chevrolet Silverado 1500

2008 HVAC Heating, Ventilation, and Air Conditioning - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra &

Silverado

NOISE DIAGNOSIS - HVAC MODULE

25

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

Step

Action

Yes

No

1

Were you sent here from Symptoms or another
diagnostic table?

Go to Step 2

Go to Symptoms
- HVAC
Systems -
Manual
or
Go to Symptoms
- HVAC
Systems -
Automatic

2

1. Start the engine.

2. Cycle through all of the following:

Blower motor speeds

HVAC modes

Temperature control settings

3. Determine the type of noise:

Scrape, pop

Tick/click, chirp or groaning

Air rush/whistle

Is a scrape or pop noise evident when selecting
modes or temperature settings?

Go to Step 6

Go to Step 3

3

Is a tick/click, chirping, groaning or scraping
noise present, but decreases as blower motor
speed is decreased?

Go to Step 6

Go to Step 4

4

Is an air rush/whistle noise evident in all modes
but not all temperature settings?

Go to Step 6

Go to Step 5

5

Is an air rush/whistle noise evident only in
defrost or floor mode?

Go to Step 6

Go to Step 6

2008 Chevrolet Silverado 1500

2008 HVAC Heating, Ventilation, and Air Conditioning - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra &

Silverado

ODOR DIAGNOSIS

6

Remove the instrument panel I/P carrier. Refer
to Instrument Panel Carrier Replacement .
Is the action complete?

Go to Step 7

-

7

1. Inspect the air flow doors for proper

operation.

2. Inspect the ducts for obstructions or

foreign materials.

Were any of these conditions found?

Go to Step 10

Go to Step 8

8

Inspect the mode and temperature doors and
seals for warping or cracking.
Are the doors in normal condition?

Go to Step 11

Go to Step 9

9

Replace the appropriate door and/or seals.
Is the repair complete?

Go to Step 11

-

10

Remove any obstructions or foreign material
found.
Is the action complete?

Go to Step 11

-

11

Install the I/P carrier. Refer to Instrument
Panel Carrier Replacement .
Is the action complete?

Go to Step 12

-

12

Operate the system to verify the repair.
Did you find and correct the condition?

System OK

Go to Step 2

Step

Action

Yes

No

1

Were you sent here from Symptoms or another
diagnostic table?

Go to Step 2

Go to Symptoms
- HVAC
Systems -
Manual
or
Go to Symptoms
- HVAC
Systems -
Automatic

1. Sit inside the vehicle.

2. Close all of the doors and windows.

2008 Chevrolet Silverado 1500

2008 HVAC Heating, Ventilation, and Air Conditioning - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra &

Silverado