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Noise Diagnosis - Air Conditioning (A/C) System

Noise Diagnosis - Air Conditioning (A/C) System


Step Action Yes No
1
Were you sent here from Symptoms or another diagnostic table? Go to Step 2 Go to Symptoms - HVAC Systems - Automatic
2

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

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 ON?
Go to Step 3 Go to Step 6
3
With the engine OFF, inspect the drive belt for excessive wear. Refer to Drive Belt Falls Off and Excessive Wear Diagnosis . Is the drive belt excessively worn? Go to Step 14 Go to Step 4
4
Inspect the drive belt tension. Refer to Drive Belt Tensioner Diagnosis . Is the drive belt tension correct? Go to Step 15 Go to Step 5
5
Inspect the drive belt for excessive oil coverage. Is the drive belt covered with oil? Go to Step 13 Go to Step 6
6

1. Start the engine.

2. Ensure that the A/C is ON.


Is the compressor locked up?
Go to Step 19 Go to Step 7
7
Using a stethoscope, listen to the A/C compressor for any abnormal noises. Is the compressor causing an abnormal noise? Go to Step 11 Go to Step 8
8
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 16 Go to Step 9
9

1. Idle the engine.

2. Engage the A/C.

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 21 Go to Step 10
10

1. 1. Idle the engine in PARK with the A/C on.

2. 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 17 Go to Step 20
11
Verify that the A/C system is properly charged. Refer to Refrigerant System Specifications . Is the A/C system properly charged? Go to Step 19 Go to Step 16
12
Recharge the A/C system to specification. Refer to Refrigerant Recovery and Recharging (Belt Driven Compressor) . Is the abnormal compressor noise still present? Go to Step 20 Go to Step 21
13
Repair the oil leak. Refer to the appropriate repair procedure in Engine Mechanical. Is the repair complete? Go to Step 21 -
14
Replace the drive belt. Refer to Drive Belt Replacement . Is the replacement complete? Go to Step 21 -
15
Replace the drive belt tensioner. Refer to Drive Belt Replacement . Is the replacement complete? Go to Step 21 -
16
Repair or replace the A/C compressor mounting component. Is the repair complete? Go to Step 21 -
17
Repair or replace the component which is causing the moaning concern as needed. Is the repair complete? Go to Step 21 -
18
Correctly route or insulate the A/C component. Is the repair complete? Go to Step 21 -
19
Replace the A/C compressor. Refer to A/C compressor, replacement (LF1) A/C compressor, replacement (LAU) . Is the replacement complete? Go to Step 21 -
20
The concern may be caused by an engine related component. Refer to Vibration Analysis - Engine . Did you find and correct the condition? Go to Step 21 -
21
Operate the system in order to verify the repair. Did you find and correct the condition? System OK Go to Step 2