Did you perform the HVAC Diagnostic System Check?

Go to Step 2

Go to Diagnostic System Check - HVAC Systems - Automatic in HVAC Systems--Automatic

1. Sit inside the vehicle.
2. Close the vehicle doors and windows.
3. Turn ON the ignition, with the engine OFF.
4. Set the blower speed to high.
5. Set the temperature control to full cold.
6. Set the mode control so the air comes out of the IP vents.
7. Set the A/C to OFF.

Is an abnormal noise present?

Go to Noise Diagnosis - Blower Motor

Go to Step 3

1. Start the engine and allow the engine to idle in PARK.
2. Turn the A/C ON.

Is the A/C clutch engaged and supplying cold air to the passenger compartment?

Go to Step 4

Go to HVAC Compressor Clutch Does Not Disengage in HVAC Systems--Automatic

A/C system noises can be generally categorized into 3 areas:

Is a screech/squealing noise heard when the A/C clutch is engaged?

Go to Step 5

Go to Step 11

Inspect the A/C compressor drive belt for excessive wear or for oil coverage. Refer to Drive Belt Excessive Wear Diagnosis

Is the drive belt excessively worn or covered with oil?

Go to Step 6

Go to Step 7

1. Repair the source of the oil leak. Refer to Oil Leak Diagnosis in Engine Mechanical.
2. Replace the A/C compressor drive belt. Refer to Drive Belt Replacement in Engine Mechanical

Did you complete the repair?

Go to Step 25

--

Is the A/C compressor clutch slipping or is the compressor locked up?

Go to Step 8

Go to Step 9

1. Verify that the A/C system is properly charged.
2. Repair or replace the A/C compressor/component as necessary.

Did you complete the repair?

Go to Step 25

--

1. Start the engine and allow the engine to idle in PARK.
2. Engage the A/C compressor clutch.
3. Use a stethoscope to examine the A/C compressor drive belt idler pulley and the tensioner for any abnormal noises. Refer to Drive Belt Tensioner Diagnosis .

Are the idler pulley and the tensioner operating without abnormal noise?

Go to Step 10

Go to Step 11

Replace the A/C compressor drive belt idler pulley or the tensioner as necessary. Refer to Drive Belt Tensioner Replacement

Did you complete the repair?

Go to Step 25

--

Does a moaning noise exist when the A/C clutch is engaged?

Go to Step 12

Go to Step 20

Perform a system performance test to verify that the A/C system is properly charged. Refer to Air Conditioning (A/C) System Performance Test

Is the A/C system properly charged?

Go to Step 14

Go to Step 13

1. Recover and recharge the A/C system. Refer to Refrigerant Recovery and Recharging .
2. Start the engine and allow the engine to idle in PARK.
3. Engaged the A/C compressor clutch.

Does the moaning noise exist when the A/C clutch is engaged?

Go to Step 14

Go to Step 25

Inspect the A/C compressor mounting, idler pulley, and tensioner for concerns using a stethoscope.

Are any of these components loose, damaged or excessively worn?

Go to Step 15

Go to Step 16

Repair or replace the A/C compressor mounting, idler pulley, or tensioner/tensioner pulley as needed.

Did you complete the repair?

Go to Step 25

--

1. A/C compressor clutch engaged and engine idling in PARK.
2. Using a stethoscope, move around the entire refrigerant plumbing system and check for any abnormal noises that are caused by component ground-out.

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

Go to Step 17

Go to Step 18

Repair or replace the component which is causing the moaning condition as needed.

Did you complete the repair?

Go to Step 25

--

Does the condition go away with the A/C clutch disengaged and the engine idling in PARK?

Go to Step 19

Go to Diagnostic Starting Point - Vibration Diagnosis and Correction in Vibration Diagnosis and Correction

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

Did you complete the repair?

Go to Step 25

--

Does a vibration or rattle noise exist when the A/C clutch is engaged?

Go to Step 21

System OK

Using a stethoscope, inspect the A/C compressor mounting, the idler pulley, and the tensioner for noise conditions.

Are any of these components loose, damaged or excessively worn?

Go to Step 15

Go to Step 22

1. A/C compressor clutch engaged and engine idling in PARK.
2. Using a stethoscope, move around the entire A/C system and listen for any abnormal noises that are caused by a component.

Are any of the A/C components causing an abnormal noise?

Go to Step 23

Go to Step 24

Repair or replace the component which is causing the vibration/rattle condition as needed.

Did you complete the repair?

Go to Step 25

--

Is the vibration/rattle coming from inside the A/C compressor?

Go to Step 19

Go to Diagnostic Starting Point - Vibration Diagnosis and Correction in Vibration Diagnosis and Correction

Operate the system in order to verify the repair.

Did you find and correct the condition?

System OK

Go to Step 2