Chevrolet Silverado / GMC Sierra. Service manual — part 2310

2

3. Start the engine.

4. Allow the engine idle at normal operating

temperature.

5. Select the maximum blower speed.

6. Select the PANEL air outlet mode.

7. Select the coldest temperature setting.

8. Cycle through all of the blower speeds,

modes and temperatures to define what
type of odor is present.

Musty smell

Coolant smell

Oil smell

Does the odor have a musty smell?

Go to Step 3

Go to Step 8

3

Inspect the HVAC air inlet grille for debris.
Is debris present?

Go to Step 4

Go to Step 5

4

Remove any debris.
Is the action complete?

Go to Step 15

-

5

Inspect for wet carpeting.
Is the carpet wet?

Go to Step 6

Go to Step 14

6

Inspect for the following conditions:

Water leaks around the windshield

Blockage of the HVAC module drain

Leaks around the door seals

Is a leak present?

Go to Step 7

Go to Step 14

7

Repair the leak as necessary.
Is the repair complete?

Go to Step 15

-

8

Does the odor have a coolant smell?

Go to Step 9

Go to Step 12

9

Inspect the cooling system for leaks. Refer to
Loss of Coolant .
Is a leak present?

Go to Step 10

Go to Step 12

10

Inspect for coolant leaking inside the vehicle or
for a film build-up on the windshield.

2008 Chevrolet Silverado 1500

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

Silverado

REPAIR INSTRUCTIONS

ODOR CORRECTION

Eliminating Air Conditioning Odor

Odors may be emitted from the air conditioning system primarily at start up in hot, humid
climates. The following conditions may cause the odor:

Debris is present in the HVAC module.

Microbial growth on the evaporator core

When the blower motor fan is turned on, the microbial growth may release an unpleasant musty
odor into the passenger compartment. To remove odors of this type, the microbial growth must be
eliminated. Perform the following procedure:

Deodorize the evaporator core using Deodorizing Aerosol Kit.

Is the condition present?

Go to Step 11

Go to Step 15

11

Replace the heater core. Refer to Heater Core
Replacement.
Is the repair complete?

Go to Step 15

-

12

Does the odor have an oily smell?

Go to Step 13

Go to Step 15

13

1. Inspect the engine compartment for any

leaks. Refer to the following procedures:

Oil Leak Diagnosis

Fluid Leak Diagnosis

Power Steering Fluid Leaks

2. Repair any oil leaks.

Is the repair complete?

Go to Step 15

-

14

A musty odor can be caused by mold or mildew
build-up on the evaporator, the heater core, or
inside of the HVAC module. Refer to Odor
Correction.
Is the action complete?

Go to Step 15

-

15

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

System OK

Go to Step 2

2008 Chevrolet Silverado 1500

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

Silverado

Perform the following steps in order to deodorize the A/C system:

1. Ensure that the plenum which draws outside air into the HVAC module is clear of debris.

2. Disable the A/C compressor clutch operation by disconnecting the clutch coil electrical

connector.

3. Dry the evaporator core by performing the following steps:

1. Start the engine.

2. Select the warmest temperature setting.

3. Select the recirculation mode.

4. Run the blower motor on high for 10 minutes.

4. Locate an area in the air conditioning duct between the blower motor and the evaporator

core downstream of the blower motor.

5. Drill a 3.175 mm (0.125 in) hole where the hole will not interfere with or damage the

following components:

The blower motor

The evaporator core

Any other operating part the of system

6. Wear safety goggles and latex gloves in order to perform the following actions:

1. Select the maximum blower speed.

2. Insert the deodorizer extension tube into the hole to the mark on the extension tube.

3. Use short spray bursts and vary the direction of spray for a 2-3 minute period of time.

7. Shut the engine OFF. Allow the vehicle to sit for 3-5 minutes.

8. Seal the 3.175 mm (0.125 in) hole with body sealer or RTV gasket compound.

9. Start the engine.

10. Operate the blower motor on high for 15-20 minutes to dry.

11. Reconnect the A/C compressor clutch coil electrical connector.

12. Verify proper clutch operation.

REFRIGERANT RECOVERY AND RECHARGING

Tools Required

J 43600 ACR 2000 Air Conditioning Service Center. See Special Tools.

J 45037 A/C Oil Injector. See Special Tools.

Recovery and Recharge

2008 Chevrolet Silverado 1500

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

Silverado

The J 43600 is a complete air conditioning service center for R-134a. See Special Tools. The

CAUTION: Avoid breathing the A/C Refrigerant 134a (R-134a) and the

lubricant vapor or the mist. Exposure may irritate the eyes,
nose, and throat. Work in a well ventilated area. In order to
remove R-134a from the A/C system, use service equipment
that is certified to meet the requirements of SAE J 2210 (R-
134a recycling equipment). If an accidental system discharge
occurs, ventilate the work area before continuing service.
Additional health and safety information may be obtained
from the refrigerant and lubricant manufacturers.

CAUTION: For personal protection, goggles and gloves should be worn

and a clean cloth wrapped around fittings, valves, and
connections when doing work that includes opening the
refrigerant system. If R-134a comes in contact with any part of
the body severe frostbite and personal injury can result. The
exposed area should be flushed immediately with cold water
and prompt medical help should be obtained.

NOTE:

R-134a is the only approved refrigerant for use in this vehicle. The
use of any other refrigerant may result in poor system performance
or component failure.

NOTE:

To avoid system damage use only R-134a dedicated tools when
servicing the A/C system.

NOTE:

Use only Polyalkylene Glycol Synthetic Refrigerant Oil (PAG) for
internal circulation through the R-134a A/C system and only 525
viscosity mineral oil on fitting threads and O-rings. If lubricants
other than those specified are used, compressor failure and/or
fitting seizure may result.

NOTE:

R-12 refrigerant and R-134a refrigerant must never be mixed, even
in the smallest of amounts, as they are incompatible with each
other. If the refrigerants are mixed, compressor failure is likely to
occur. Refer to the manufacturer instructions included with the
service equipment before servicing.

2008 Chevrolet Silverado 1500

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

Silverado