GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Isuzu 🢒 2004 🢒 Isuzu - N Series 🢒 Engine 🢒 Engine Mechanical - 4.8L, 5.3L, and 6.0L 🢒 Drive Belt Chirping Diagnosis

Diagnostic Aids

The chirping noise may be intermittent due to moisture on the drive belt or the accessory drive pulley. In order to duplicate the customer concern, it may be necessary to spray a small amount of water onto the drive belt. If spraying water onto the drive belt duplicates the symptom, cleaning the accessory drive pulley may be the most probable solution.

A loose or improperly installed suspension body component or other item on the vehicle may also cause the chirping noise.

Test Description

The numbers below refer to the steps in the diagnostic table.

  1. The chirping noise may not be engine related. This step verifies that the engine is making the noise. If the engine is not making the noise do not proceed any further in this table.

    2.

  2. The noise may be an internal engine noise. Remove the drive belt and operate the engine for a few seconds. This step verifies if the chirping noise is related to the drive belt or not. With the drive belt removed, the water pump does not operate and the engine may overheat. Diagnostic trouble codes (DTCs) may set when the engine is operated with the drive belt removed.

    3.

  3. Inspect the drive belt for signs of pilling. Pilling is small balls, pills or strings in the drive belt grooves, caused by the accumulation of rubber dust.

    4.

  4. Misalignment of the accessory drive pulley may be caused from improper mounting or incorrect installation of an accessory drive component, or the pulley may be bent inward or outward from a previous repair. Test for a misaligned accessory drive pulley using a straight edge in the pulley grooves across two or three pulleys. If a misaligned pulley is found, refer to that accessory drive component for the proper removal and installation procedure for that pulley.

  5. Inspection of the fasteners can eliminate the possibility that an incorrect bolt, nut, spacer or washer was installed.

    6.

  6. Inspection of the accessory drive pulley should include inspecting for bends, dents or other damage to the pulley that would prevent the drive belt from seating properly in the pulley grooves or on the smooth surface of the pulley when the back side of the drive belt is used to drive the pulley.

    7.

  7. Replacing the drive belt when it is not damaged or there is not excessive pilling is only a temporary repair.

Step

Action

Yes

No

Notice: Refer to Belt Dressing Notice in the Preface section.

DEFINITION: The following items are indications of chirping:

    • A high pitched noise that is heard once per revolution of the drive belt or accessory drive pulley.
    • Chirping may occur on cold damp startup conditions and will subside once the vehicle reaches normal operating temperature.

1

Did you review the Symptoms - Engine Mechanical, and perform the necessary inspections?

Go to Step  2

Go to Symptoms - Engine Mechanical

2

Verify that there is a chirping noise.

Does the engine make the chirping noise?

Go to Step 3

Go to Diagnostic Aids

3

  1. Remove the drive belt. Refer to Drive Belt Replacement - Accessory or Drive Belt Replacement - Air Conditioning.
  2. Operate the engine for no longer than 30-40 seconds.

Does the chirping noise still exist?

Go to Engine Noise on Start-Up, but Only Lasting a Few Seconds

Go to Step 4

4

Inspect for severe drive belt pilling exceeding 1/3 of the drive belt groove depth.

Does the drive belt grooves have pilling?

Go to Step 5

Go to Step 6

5

Clean the accessory drive pulley with a suitable wire brush.

Did you clean the accessory drive pulley?

Go to Step 15

--

6

Inspect for a misaligned accessory drive pulley.

Is there a misaligned accessory drive pulley?

Go to Step 7

Go to Step 8

7

Replace and/or repair the misaligned accessory drive pulley.

Did you replace and/or repair the misaligned accessory drive pulley?

Go to Step 15

--

8

Inspect for a bent or cracked accessory drive bracket.

Did you find any bent or cracked accessory drive bracket?

Go to Step 9

Go to Step 10

9

Replace the bent and/or cracked accessory drive bracket.

Did you replace the bent and/or cracked accessory drive bracket?

Go to Step 15

--

10

Inspect for incorrect, loose and/or missing fasteners.

Did you find any incorrect, loose and/or missing fasteners?

Go to Step 11

Go to Step 12

11
  1. Replace any incorrect and/or missing fasteners.
  2. Tighten any loose fasteners. Refer to Fastener Tightening Specifications .

Did you replace and/or tighten the fasteners?

Go to Step 15

--

12

Inspect for a bent accessory drive pulley.

Did you find a bent accessory drive pulley?

Go to Step 13

Go to Step 14

13

Replace the bent accessory drive pulley.

Did you replace the accessory drive pulley?

Go to Step 15

--

14

Replace the drive belt. Refer to Drive Belt Replacement - Accessory or Drive Belt Replacement - Air Conditioning.

Did you replace the drive belt?

Go to Step 15

--

15
  1. Clear any codes.
  2. Run the engine in order to verify the repair.

Does the chirping noise still exist?

--

System OK